BAA Comet Section : Periodic Comets 300 - 399

Updated 2021 March 22


  • 300P/Catalina
  • 301P/LINEAR-NEAT
  • 302P/Lemmon-PanSTARRS
  • 303P/NEAT
  • 304P/Ory
  • 305P/Skiff
  • 306P/LINEAR
  • 307P/LINEAR
  • 308P/Lagerqvist-Carsenty
  • 309P/LINEAR
  • 310P/Hill
  • 311P/PanSTARRS
  • 312P/NEAT
  • 313P/Gibbs
  • 314P/Montani
  • 315P/LONEOS
  • 316P/LONEOS-Christensen
  • 317P/WISE
  • 318P/McNaught-Hartley
  • 319P/Catalina-McNaught
  • 320P/McNaught
  • 321P/SOHO
  • 322P/SOHO
  • 323P/SOHO
  • 324P/La Sagra
  • 325P/Yang-Gao
  • 326P/Hill
  • 327P/Van Ness
  • 328P/LONEOS-Tucker
  • 329P/LINEAR-Catalina
  • 330P/Catalina
  • 331P/Gibbs
  • 332P/Ikeya-Murakami
  • 333P/LINEAR
  • 334P/NEAT
  • 335P/Gibbs
  • 336P/McNaught
  • 337P/WISE
  • 338P/McNaught
  • 339P/Gibbs
  • 340P/Boattini
  • 341P/Gibbs
  • 342P/SOHO
  • 343P/NEAT-LONEOS
  • 344P/Read
  • 345P/LINEAR
  • 346P/Catalina
  • 347P/PanSTARRS
  • 348P/PanSTARRS
  • 349P/Lemmon
  • 350P/McNaught
  • 351P/Wiegert-PanSTARRS
  • 352P/Skiff
  • 353P/McNaught
  • 354P/LINEAR
  • 355P/LINEAR-NEAT
  • 356P/WISE
  • 357P/Hill
  • 358P/PanSTARRS
  • 359P/LONEOS
  • 360P/WISE
  • 361P/Spacewatch
  • 362P/Spacewatch
  • 363P/Lemmon
  • 364P/PanSTARRS
  • 365P/PanSTARRS
  • 366P/Spacewatch
  • 367P/Catalina
  • 368P/NEAT
  • 369P/Hill
  • 370P/NEAT
  • 371P/LINEAR-Skiff
  • 372P/McNaught
  • 373P/Rinner
  • 374P/Larson
  • 375P/Hill
  • 376P/LONEOS
  • 377P/Scotti
  • 378P/McNaught
  • 379P/Spacewatch
  • 380P/PanSTARRS
  • 381P/LINEAR-Spacewatch
  • 382P/Larson
  • 383P/Christensen
  • 384P/Kowalski
  • 385P/Hill
  • 386P/PanSTARRS
  • 387P/Boattini
  • 388P/Gibbs
  • 389P/Siding Spring
  • 390P/Gibbs
  • 391P/Kowalski
  • 392P/LINEAR
  • 393P/Spacewatch-Hill
  • 394P/PanSTARRS
  • 395P/Catalina-NEAT
  • 396P/Leonard
  • 397P/Lemmon
  • 398P/Boattini
  • 399P/PanSTARRS
  • Comets 1 - 99
  • Comets 100 - 199
  • Comets 200 - 299
  • Comets 300 - 399
  • Comets 400 - 499
  • Not numbered objects
  • When observing a comet please try to forget how bright you think the comet should be, what it was when you last viewed it, what other observers think it is or what the ephemeris says it should be.

    The equations for the light curves of comets that are currently visible use only the raw observations and should give a reasonable prediction for the current brightness. If the comet has not yet been observed or has gone from view a correction for aperture is included, so that telescopic observers should expect the comet to be fainter than given by the equation. The correction is about 0.033 per centimetre. Values for the r parameter given in square brackets [ ] are assumed. The form of the light curve is either the standard m = H0 + 5 log d + K0 log r or the linear brightening m = H0 + 5 log d + L0 abs(t - T + D0) where T is the date of perihelion, t the present and D0 an offset, if L0 is +ve the comet brightens towards perihelion and if D0 is +ve the comet is brightest prior to perihelion.


    300P/Catalina = 2005 JQ5 = 2014 G2
    An apparently asteroidal object of 17th magnitude found by the Catalina Sky Survey on 2005 May 6.28 has been found to show cometary features. It reached perihelion at 0.83 au in late July 2005 and has a period of 4.4 years. The comet reached magnitude 10.5.

    The comet was recovered by M. Masek, J. Cerny, J. Ebr, M. Prouza, P. Kubanek, M. Jelinek, K. Honkova and J. Jurysek at the Pierre Auger Observatory, Malarque with the 0.3m reflector on April 9.39. [MPEC 2014-G70, 2014 April 10]. The comet returns to perihelion 0.1 days earlier than predicted.

    The comet can make close approaches to Venus, Earth and Mars. Its last close approach to Earth was at the discovery apparition in 2005, when it came to 0.10 au and in 2036 it will approach to 0.06 au. It will approach within 0.08 au of Mars in 2132 and approached Venus to 0.09 au in 1957.  The June epsilon Ophiuchid meteor shower was active between 2019 June 19 and 26 and this shower is associated with the comet.


    301P/LINEAR-NEAT = 2001 BB50 = 2014 K1
    S. Pravdo, K. Lawrence, and E. Helin, Jet Propulsion Laboratory, reported the discovery of an 18th mag comet on 2001 March 20 CCD images taken with the NEAT 1.2-m reflector at Haleakala, the object showing a short eastward tail, a nuclear condensation of size < 3", and a coma diameter of about 10". T. B. Spahr, Minor Planet Center, linked this object first with an object reported as asteroidal by LINEAR on March 18 (m_2 = 19.5) and then to the LINEAR object 2001 BB_50, observed on January 21 and 26 (MPS 25734). Following posting on the NEO Confirmation Page, C. Jacques, Belo Horizonte, Brazil, also reported a 10" coma and m_1 = 18.6 on CCD images taken on March 21 (0.3-m reflector). Full astrometry and the orbital elements appear on MPEC 2001-F26. [IAUC 7601, 2001 March 21] The comet has a perihelion distance of 2.35 au and is intrinsically faint. Its period is 13.6 years.

    2001 BB50 (P/LINEAR-NEAT) was recovered in images from PanSTARRS taken on 2014 May 17.28, with earlier images taken at the SATINO remote observatory, Haute Province on 2014 March 1.93. The comet will return to perihelion 1.76 days earlier than predicted and has a period of 13.7 years.


    302P/Lemmon-PanSTARRS = 2007 RJ236 = 2014 K2
    A 21st magnitude comet discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on April 29.36, was linked to asteroid 2007 RJ236 discovered during the Mt Lemmon survey on 2007 September 13.30. It was also linked to observations made by the Purple Mountain Observatory in 2007 August. [MPEC 2014-K28, 2014 May 23] The comet is at perihelion at 3.3 au in 2016 April and has a period of 8.86 years.
    303P/NEAT = 2003 U3 = 2014 L1
    NEAT discovered an 19th mag comet on 2003 October 22.29. It was past perihelion at 2.5 au in late April and had a period around 11.5 years.

    K. Lawrence, Jet Propulsion Laboratory, reports the discovery by the NEAT project of a 19th magnitude comet on 2003 October 22.29. Observations by J. Young at Table Mountain on October 23.2 UT show a 3" coma with a short, broad, fan-shaped tail about 8" long spanning p.a. 255-285 deg. [IAUC 8230, 2003 October 23]

    2003 U3 (P/NEAT) was recovered in images taken at the ESA Optical Ground Station in Tenerife with the 1.0m reflector by P Ruiz. The comet will return to perihelion 1.80 days earlier than predicted and has a period of 11.4 years.    [MPEC 2014-L12, 2014 June 2]


    304P/Ory = 2008 Q2 = 2014 L4
    An 18th magnitude apparently asteroidal object discovered by Michel Ory of Delemont, Switzerland, on CCD images obtained with a 0.61-m f/3.9 reflector at Vicques was found to show cometary characteristics after posting on the NEOCP. The comet has a period of 5.8 years with perihelion at 1.4 au. It was at a perihelic opposition.

    Michel Ory is a Swiss amateur astronomer and president of the Société jurassienne d'astronomie, which has a well equipped observatory in the foothills of the Jura.

    The comet passed 0.3 au from Jupiter in November 2005, before which the perihelion distance was a little larger.

    2008 Q2 was recovered by Hidetaka Sato in images taken with the iTelescope 0.51m astrograph at Siding Spring on 2014 June 2.79. The comet is very close to the prediction by B. G. Marsden on MPC 65935. It has a period of 5.8 years.  [MPEC 2014-M10, CBET 3906, 2014 June 18].

    In 2021 January it briefly appeared on the PCCP as C4PEAU2.


    305P/Skiff = 2004 V1 = 2014 N1
    Brian Skiff discovered an 18th magnitude comet on LONEOS images taken with the 0.59-m Schmidt on November 4.08. Prediscovery LINEAR images showed that it ws approaching perihelion at 1.42 au in early December and had a period of 10.0 years.

    B. Skiff, Lowell Observatory, reports his discovery of a comet on LONEOS images obtained on Nov. 4.1 UT with the 0.59-m Schmidt telescope, the object showing a moderately condensed coma of diameter 25" and a weak tail 50" long in p.a. 75 deg. Following posting on the "NEO Confirmation Page", B. L. Stevens (Las Cruces, NM, 0.3-m Schmidt-Cassegrain telescope) reports that his CCD images taken on Nov. 4.2 show a 30" tail in p.a. 55 deg. [IAUC 8426, 2004 November 4]

    Gareth Williams found images of 2004 V1 (P/Skiff) in images taken taken with the PanSTARRS 1 1.8m Ritchey-Chretien on July 3.51. The comet will return to perihelion 0.32 days earlier than predicted and has a period of 9.9 years.  [CBET 3918, MPEC 2014-N43, 2014 July 7]


    306P/LINEAR = 2003 O3 = 2014 M5
    A 19th magnitude comet was discovered by LINEAR on 2003 July 30.39, although other CCD observers estimated it at 18th magnitude. It was confirmed as cometary by Peter Birtwhistle amongst others. The comet reached perihelion at 1.25 au in mid August. It passed 0.3 au from Jupiter in 1979 November and the period is 5.5 years.

    An apparently asteroidal object reported by LINEAR, and posted on the NEO Confirmation Page, was found to be apparently cometary on CCD images taken by P. Birtwhistle (Great Shefford, U.K., 0.30-m reflector; very faint tail about 10" long in p.a. approximately 270-280 deg on July 31.10 and Aug. 2.08 UT; mag 18.1 and coma diameter about 5" on Aug. 2.08), by J. Ticha and M. Tichy (Klet, 1.06-m KLENOT telescope; diffuse with a wide tail in p.a. 260 deg on Aug. 3.01), and by J. McGaha (near Tucson, AZ; possible tail spike 5" long in p.a. 300 deg on Aug. 3.38 with a 0.30-m reflector; possible fan-shaped tail 5" long in p.a. 260 deg on Aug. 5.33 with a 0.62-m reflector). The preliminary orbital elements indicate that the comet passed 0.3 au from Jupiter in Nov. 1979. [IAUC 8174, 2003 August 5]

    2003 O3 (P/LINEAR) was recovered by Hidetaka Sato in images taken with the iTelescope 0.51m astrograph at Siding Spring on June 21.77. The comet was missed at its 2009 return and is close to the prediction in the 2014 ICQ Handbook. It has a period of 5.5 years with perihelion at 1.3 au.  [MPEC 2014-N76, CBET 3922, 2014 July 14]


    307P/LINEAR = 2000 QJ46 = 2014 O1
    A 19th magnitude asteroid found by LINEAR on 2000 August 24.27 was found in 2005 October to show a coma and tail on archival Sloan Digital Sky Survey images taken just over a week later. The comet has a 14.4 year period, with perihelion at 1.93 au in 2000 December.

    A team of observers at the European Space Agency's Optical Ground Station recovered 2000 QJ46 (P/LINEAR) with the 1.0m reflector on 2014 July 25.15. The indicated correction to the prediction by B. G. Marsden on MPC 75735 is Delta(T) = -0.24 day.  [CBET 3923, MPEC 2014-O44, 2014 July 27] The comet has a period of 14 years and reaches perihelion at 1.9 au in December.

    The comet is one of those suspected to have undergone nuclear splitting according to the list of Marcos & Marcos [Dynamically correlated minor bodies in the outer solar system, MNRAS, 474, 838, 2018 February]. They link it to 16P/Brooks.


    308P/Lagerqvist-Carsenty = 1997 T3 = 2014 O2
    Uri Carsenty and Andreas Nathues, of the DLR Institute of Planetary Exploration, Berlin discovered a 19th mag cometary object on 1997 October 5.1 during the course of the Uppsala-DLR Trojan Survey, in collaboration with C-I Lagerkvist, S Mottola and G Hahn. [IAUC 6754, 1997 October 7]. It is in a distant elliptical orbit with a period of 19.7 years. The comet was not named until January 1998, when it was named after the discoverer and person who found that it was a cometary object [IAUC 6811, 1998 January 23]

    A team of observers at the European Space Agency's Optical Ground Station recovered 1997 T3 (P/Lagerqvist-Carsenty) with the 1.0m reflector on 2014 July 29.08. The indicated correction to the prediction by B. G. Marsden on MPC 79348 is Delta(T) = -1.28 days. [CBET 3925, MPEC 2014-O65, 2014 July 30] The comet has a period of 17 years and reaches perihelion at 4.2 au in 2015 May.


    309P/LINEAR = 2005 Q4 = 2014 Q4
    A 19th magnitude, asteroidal object discovered by LINEAR on August 31.40 and posted on the NEOCP was shown to have a tail by J Lacruz (Madrid) and J Young (Table Mountain, USA). The comet reaches perihelion at 1.75 AU at the end of September. It is in an eliptical orbit with a period of 9.4 years.

    Krisztian Sarneczky recovered 2005 Q4 (P/LINEAR) with a 0.6m Schmidt on 2014 August 23.00, with PanSTARRS images from the same night later found by Gareth Williams. The indicated correction to the prediction by Gareth Williams on MPC 75706 is Delta(T) = -0.26 day.  [CBET 3937, MPEC 2014-Q39, 2014 August 24] The comet has a period of 9.4 years and reaches perihelion at 1.7 au in 2015 February.


    310P/Hill = 2006 S6 = 2014 Q5
    This was the second of two comet discoveries by Rik Hill on the same night, 2006 September 28. It was of 18th magnitude. and found on September 28.40. It was at perihelion at 2.4 au in mid 2006 October.

    Krisztian Sarneczky recovered 2006 S6 (P/Hill) with a 0.6m Schmidt at the Piszkesteto Station of Konkoly Observatory on 2014 August 24.98. The indicated correction to the prediction by Gareth Williams on MPC 79348 is Delta(T) = -0.32 day.  [CBET 3938, MPEC 2014-Q53, 2014 August 26] The comet has a period of 8.5 years and reaches perihelion at 2.4 au in 2015 April.


    311P/PanSTARRS = 2013 P5
    Pan-STARRS discovered a 21st magnitude comet on 2013 August 15.50.  [MPEC 2013-Q37, 2013 August 27]  It reached perihelion at 1.9 au in 2014 April and has a low eccentricity and a very short period of around 3.2 years.  There are some similarities between its orbit and that of Flora group asteroids and it is probably another example of a Main Belt Comet. The HST took images of it on September 10 and 23, showing a complex tail structure that might be linked to rotation rate.  It was numbered in 2014 once observations extended over a complete orbit.

    A paper by Dave Jewitt et al in Astronomical Journal suggests that the comet is a close binary with a period of about 0.8 days and a mass ratio of about 1:6. One of the components may be a fast rotator, which could explain the behaviour in 2013, when there were nine dust ejection events over about 250 days, which could have been caused by landsliding.


    312P/NEAT = 2001 Q11 = 2014 R2
    In March 2010 Maik Meyer, Limburg, Germany, discovered a 19th magnitude comet on images obtained by the NEAT project on three nights at Palomar and on five nights at Haleakala during August - December 2001. The August 18.47 Palomar discovery-night images show a 21" tail in p.a. 256 deg, and there was a 0'.2 tail in p.a. 264 deg on the August 22 Haleakala frames. The August 18 observations were reported (though not as being cometary) by NEAT at the time (mag 18.6-18.7), but the object was never followed up; likewise for four LONEOS observations (mag 17.9) on October 24. The comet was at perihelion in 2001 June and has a period of around 6.2 years. Searches of relevant frames by Meyer and others have so far failed to show the comet at its return in 2007. [IAUC 9129, 2010 March 19]

    2001 Q11 (P/NEAT) was recovered in images taken by Eric Christensen at Mt Lemmon with the 1.5m reflector on September 6.45.  After the object was posted on the PCCP, Hidetaka Sato was able to find the comet in images taken on July 28.82.  The comet will return to perihelion 0.68 days earlier than predicted and has a period of 6.4 years.  It was discovered by Maik Meyer in 2010 in images taken in 2001, though no images could be found from the 2007 return. [CBET 3971, MPEC 2014-R91, 2014 September 12]


    313P/Gibbs = 2003 S10 = 2014 S4
    Alex Gibbs discovered a 19th magnitude comet on September 24.31 on images taken during the Catalina Sky Survey with the 0.68m Schmidt. Subsequently pre-discovery images were found in Sky Survey data. [CBET 3991, MPEC 2014-S115, 2014 September 27]. 

    With an improved orbit, it was linked to an object found in LONEOS images from September and November 2003 and was designated 2003 S10 for that return. [MPEC 2014-U24, 2014 October 20]

    The comet was at perihelion at 2.4 au in 2014 August and has a period of 5.6 years.  It is a Main Belt Comet.


    314P/Montani = 1997 G1 = 2014 U1
    1997 G1 P/Montani was announced on IAUC 6622. It was a 19th mag object discovered by Joe Montani of the Spacewatch team. It is a distant object, with a perihelion distance of 4.3 AU and a period of around 20 years.

    1997 G1 (P/Montani) was recovered on October 13.31 at the Steward Observatory, Kitt Peak by Terry Bressi and A F Tubbiolo with the 0.9m reflector.


    315P/LONEOS = 2004 VR8 = 2013 V6
    An apparently asteroidal 18th magnitude object discovered by LONEOS on 2004 November 3.35 and shown in the list of unusual asteroids, was found to be cometary by other observers. It reached perihelion at 2.38 au in early September 2005 and has a period of 10.7 years.

    An apparently asteroidal object discovered by LONEOS, designated 2004 VR_8 (cf. MPS 118755, MPEC 2004-V48), was found to show a 10"-diameter coma and a tail 16" long in p.a. 140 deg on R-band CCD observations taken by C. W. Hergenrother (Lunar and Planetary Laboratory) with the 1.54-m Kuiper reflector at Catalina on November 19.3 UT. Also, A. Nakamura (Kuma, Ehime, Japan) reports that 240-s unfiltered CCD frames taken with a 0.60-m reflector on December 8.55 and 9.55 shows to object's image to be slightly 'softer' than other field stars of similar brightness, and a possible very faint tail is visible to the southeast. [IAUC 8451, 2004 December 10]

    A possible recovery of 2004 VR8 (P/LONEOS) with the 3.5m Apache Point reflector on 2013 November 6.15 was confirmed with the same telescope on 2014 December 8.09. The indicated correction to the prediction by G. V. Willliams on MPC 84327 is Delta(T) = -0.71 day. [CBET 4038, MPEC 2014-Y45, 2014 December 24]  Jose Gonzalez noted the comet in possible minor outburst on 2017 March 15.83 when he estimated it at 12.3, with a stellar condensation.

    The comet approaches Jupiter every few orbits, most recently on 2007 August 22 when it passed 0.40 au from the planet. The encounter made small changes to the orbital elements and increased the orbital period to 11.2 years.


    316P/LONEOS-Christensen = 2005 RV25 = 2014 U5
    Eric Christensen discovered an 18th magnitude comet with the 0.5-m Uppsala Schmidt in the course of the Siding Spring Survey on 2005 October 22.25, which was confirmed by Peter Birtwhistle and Richard Miles and Rob McNaught. It was then linked to an asteroid discovered by LONEOS on September 11. It reached perihelion at 3.60 AU in 2006 November and has a period of 9.0 years.

    2005 RV25 (P/LONEOS-Christensen) was recovered on 2014 October 22.98 at the ESA Optical Ground Station, Tenerife by Diana Abreu with the 1.0m reflector. The recovery was confirmed by J D Armstrong with the Faulkes-North   [CBET 40nn, MPEC 2014-W19, 2014 November 19]  The comet has perihelion at 3.6 au in 2015 October and a period of 8.9 years. The perihelion date was around xx days earlier than those published for the equinox of perihelion.


    317P/WISE = 2010 K2 = 2015 B3
    An object noted in images from the the Wide-field Infrared Survey Explorer (WISE) satellite on May 27.18 and posted on the NEOCP was found to show cometary characteristics Jim Scotti with the Spacewatch 1.8-m reflector and Alan C. Gilmore and Pamela M. Kilmartin with the Mount John 1.0-m reflector. Further inspection of the WISE images also showed a coma and tail. The comet was at perihelion at 1.2 au in 2010 July and had a period of 5.0 years.

    PanSTARRS recovered P/2010 K2 in images taken with the 1.8m Ritchey-Chretien on 2015 January 26.46, with further images on March 18.35. The comet now has a period of 5.1 years and will reach perihelion 3.2 days earlier than previously predicted. It passed 0.71 au from Jupiter in 2012 November.


    318P/McNaught-Hartley = 1994 N2 = 2014 M6
    Malcolm Hartley took a 110 minute exposure on 1994 July 6.6 with the 1.2-m UK Schmidt Telescope at Siding Spring and found a 16m comet, which was also present on a plate taken the night before. [IAUC 6014, 1994 July 7]. The comet was approaching opposition and nearly stationary on the border of Grus and Microscopium. It proved to be a relatively distant short period comet with a period of 21 years and a perihelion distance of 2.5 au.  Aphelion is beyond the orbit of Saturn and there have been no recent approaches to it or Jupiter.

    1994 N2 (P/McNaught-Hartley) was recovered by PanSTARRS in images taken with the 1.8m Ritchey-Chretien on 2014 June 29.32, though it took further images taken at the MASTER-SAAO Observatory, Sutherland with the 0.4m reflector on 2015 March 31.1 to confirm the recovery. The comet reaches perihelion at 2.45 au in October and has a period of 20.6 years.

    5 visual observations received so far suggest a preliminary light curve of m = 9.0 + 5 log d + [10] log r


    319P/Catalina-McNaught = 2008 S1 = 2015 G1
    Rob McNaught discovered a 17th magnitude comet on September 17.41 on CCD images taken with the 0.5-m Uppsala Schmidt telescope at Siding Spring Observatory. Brian Marsden subsequently linked the comet to asteroid 2008 JK, discovered during the Catalina Sky Survey on May 2.34. The comet was therefore renamed from McNaught to Catalina-McNaught. The improved orbit shows that the comet approached to 0.18 au from Jupiter in 1990 August, before which its perihelion distance was 1.5 au. The comet was near perihelion at discovery.

    An object found in infra-red images from the NEOWISE satellite on 2015 April 5.67 was identified as the return of 2008 S1 (P/Catalina-McNaught) by Gareth Williams.  The indicated correction to the prediction on MPC 79350 is Delta(T) = -0.11 day.  The comet reaches perihelion at 1.20 au in 2015 July and has a period of 6.8 years.


    320P/McNaught = 2004 R1 = 2015 HC10
    Rob McNaught discovered an 18th magnitude comet on CCD images taken by himself with the 0.5-m Uppsala Schmidt at Siding Spring on September 2.42. Sadly although the NEO confirmation page asking for further observations suggested that the object was -0.4, this was not the case! Further observations showed that the object was a short period comet, with perihelion at 0.99 au in late August. The period was 5.49 years.

    R. H. McNaught reports his discovery of a comet on CCD images taken by himself with the 0.5-m Uppsala Schmidt telescope at Siding Spring on Sept. 2.4 UT, when the object was diffuse with a hint of a tail to the southeast. Images taken by McNaught with the Siding Spring 1.0-m f/8 reflector on Sept. 4.4 show the comet to be diffuse with a 10" coma and a tail 15" long in p.a. 110 deg. [IAUC 8398, 2004 September 4]

    J. Young (Table Mountain, 0.6-m reflector + CCD) reports that images taken in poor seeing (and at low altitude) on Sept. 6.13- 6.16 UT show a coma diameter of about 5". Additional CCD images by R. H. McNaught with the Siding-Spring 1.0-m reflector on Sept. 6.5 show an ill-defined center of brightness that is elongated in the direction of tail (and of the comet's motion). [IAUC 8400, 2004 September 6]

    An apparently asteroidal object found on images taken with the Cerro Tololo 4-m reflector by L. Allen and D. James (measured by F. Valdes) was posted on the Minor Planet Center's NEOCP webpage and then announced on MPEC 2015-H82 with the minor-planet designation 2015 HC10. Gareth Williams, F. Manca, and P. Sicoli then each identified it with comet P/2004 R1. The comet was missed at its 2010 return. The indicated correction to the prediction by S. Nakano on MPC 79350 is Delta(T) = +5.0 days. 


    321P/SOHO = 1997 J6 = 2001 D1 = 2004 X7 = 2008 S2 = 2012 M2
    In 2009, following the linkage between 2001 D1, 2004 X7 and 2008 S2, Rainer Kracht revisited the archival SOHO C2 images from 1997 and was able to secure a positive identification of the comet.

    Brian Marsden published a linked orbit on MPEC 2009-H56 [2009 April 26] and noted:

    The above computation, using nongravitational parameters A1 = +0.0002, A2 = -0.0002, is based on work by R. Kracht. Despite the poor quality of the SOHO observations, a purely gravitational computation from the four apparitions appears to leave significantly systematic residuals.
    This suggests that the object really is a comet, and should therefore be numbered as such.  The comet was again observed from SOHO in 2012, eventually being designated 2012 M2 in 2015 May and then subsequently numbered.
    322P/SOHO = 1999 R1 = 2003 R5 = 2007 R5 = 2011 R4
    A Kracht II group comet reported from SOHO C2 imagery by Bo Zhou on 2007 September 10.76 was the return of the comet predicted by Sebastian Hoenig, confirming the identity 1999 R1 = 2003 R5. The preliminary time of perihelion was September 11.1, compared to the prediction of September 11.3. Following the precedent of comets 1P, 2P and 27P a suggestion is that the comet should be re-named comet Hoenig. An alternative view is that others have also suggested possible linkages between the SOHO comet groups, eg Rainer Kracht, Brian Marsden and Maik Meyer and that deciding on who should get precedence will be difficult. The CBAT were reluctant to number it because they were not convinced that it is a comet.  The comet was again observed from SOHO in 2011, eventually being designated 2011 R4 in 2015 May and subsequently numbered as 322P/SOHO.  It was again observed in 2015, but not given a further designation. Further study suggests that the object is actually an NEO approaching its end-point and it will be vapourised.
    323P/SOHO = 1999 X3 = 2004 E2 = 2008 K10 = 2012 Q2
    This was a non-group comet discovered in C2 images by Rainer Kracht on 2008 May 31. The original orbit on MPEC 2008-O16 [2008 July 22], gave a retrograde orbit. On the basis of an identification by Rainer Kracht, Brian Marsden has computed a linked orbit with 2004 E2 and 1999 X3, which had a period of 4.2 years and a low inclination. Brian Marsden commented on MPEC 2008-S49 [2008 September 24]
    The identification is by R. Kracht. The observations, all obtained with the LASCO C2 coronagraph, are on MPEC 2006-L20, 2004-M42 and 2008-O16. The The object passed 0.058 AU from the earth on 2000 Jan. 13, 0.032 AU from Mars on 2004 May 19 and 1.17 AU from Jupiter on 2003 Feb. 1.
    The comet was again observed from SOHO in 2012, eventually being designated 2012 Q2 in 2015 May and subsequently numbered as 323P/SOHO.
    324P/La Sagra = 2010 R2 = 2015 K3
    The La Sagra team (Spain) discovered another comet on 2010 September 14.87 and were able to find pre-discovery observations from August 13.0. The object was confirmed as cometary by Peter Birtwhistle and fellow astrometrists. The comet was around 19th magnitude. It has a period of 5.5 years and was at perihelion at 2.6 au in late June. The object appears to be another main-belt comet, similar to 133P = (7968) Elst-Pizarro.

    The comet was recovered by S. S. Sheppard with the Magellan-Baade telescope in images taken in 2015 March and April, but the recovery was first reported by Jim Scotti in images taken with the Spacewatch 1.8-m telescope at Kitt Peak on 2015 May 22.43. The indicated correction to the prediction by S. Nakano is Delta(T) = -0.03 day.  [CBET 4107, MPEC 2015-K101, 2015 May 26].  The Magellan-Baade images showed a tail, which was confirmed by CFH images, according to IAUC 9276 [2015 August 3].  This notes that the object is the fourth main belt comet to show recurrent activity when near perihelion after being inactive at aphelion. 

    The comet was recovered at the 2021 return by Bruno Vauquelin at the Compustar Observatory, Rouen in images taken on 2021 July 31.


    325P/Yang-Gao = 1951 K1 = 2009 L2 = 2015 J4
    Rui Yang, Hangzhou, Zhejiang, China and Xing Gao, Urumqi, Xinjiang, China discovered a new comet on several survey images (limiting mag about 15) taken by Gao in the course of the Xingming Comet Survey using a Canon 350D camera (+ 10.7-cm f/2.8 camera lens) at Mt. Nanshan on June 15.81. The object, of 14th magnitude, but perhaps brighter visually, was identified as cometary by Yang. It was confirmed by several amateur CCD observers. [IAUC 9052, 2009 June 16]. The comet was around a month past perihelion at 1.3 au at a very favourable opposition and has a period of 6.3 years. This is the second discovery by the Xingming Survey, the first being 2008 C1 (Chen-Gao)

    Hidetaka Sato recovered 2009 L2 with the 0.51m iTelescope at Siding Spring on 2015 May 11.38 with confirming images taken on June 9 and 10. [MPEC 2015-L28, 2015 June 10].

    In 2018 Gary Kronk and Maik Meyer re-measured the positions of several X/ comets and found that X/1951 K1 was 325P.  The comet passed 0.34 au from Jupiter on 2013 February 28 and this has increased the perihelion distance to 1.43 au.  The linked orbit was finally published on MPEC 2019-F55 [2019 March 21].  It took over a year for this information to be published in a CBET, eventually appearing in CBET 4806 [2020 June 28].


    326P/Hill = 2007 V2 = 2015 P1
    BAA Member, Rik Hill discovered a 19th magnitude comet on 2007 November 9.30 in images taken during the Mt Lemmon survey with the 1.5m reflector. The comet has a period of around 8.2 years and perihelion was at 2.8 au in 2007 July.

    Krisztian Sarneczky recovered 2007 V2 (P/Hill) with the 0.6m Schmidt at Piszkesteto Station of Konkoly Observatory on August 8.02. [CBET 4134, MPEC 2015-P21, 2015 August 10].


    327P/Van Ness = 2002 Q1 = 2015 P2
    Michael E. Van Ness, Lowell Observatory, reported his discovery of a 17th mag comet with a moderately condensed 24" coma and a fan-shaped tail about 200" long in p.a. 270 deg on LONEOS images taken on 2002 August 17.44. The cometary nature was confirmed by several other CCD astrometric observers on August 18, who all reported a generally diffuse coma with diameter about 14"-25"; several also noted a tail about 25"-120" long in p.a. 260-270 deg. [IAUC 7956, 2002 August 19] It was periodic with a period of around 6.6 years and was past perihelion.

    A possible comet found by PanSTARRS on August 6.39 was tentatively identified as 2002 Q1 (P/Van Ness) by Gareth Williams. Krisztian Sarneczky independently recovered the comet on images taken with the 0.6m Schmidt at Piszkesteto Station of Konkoly Observatory on August 10.87 by A Sodor. The indicated correction to the prediction by S. Nakano on MPC 79352 is Delta(T) = +1.5 days.  [CBET 4135, MPEC 2015-P24, 2015 August 11].


    328P/LONEOS-Tucker = 1998 QP54 = 2015 S1
    1998 QP54 LONEOS-Tucker was identified as a comet by Roy A. Tucker (Tucson, AZ) whilst carrying out a CCD asteroid-astrometry program with a 0.36-m f/11 Schmidt-Cassegrain at the Goodricke-Pigott Observatory. G. V. Williams, Minor Planet Center, then identified the comet with 1998 QP54, which had been reported by E. Bowell (observer W. D. Ferris, measurer B. W. Koehn) as an apparently quite ordinary minor planet in the course of LONEOS, the Lowell Observatory Near-Earth Object Search. Williams then also identified single-night observations (also on 1998 August 28) by LINEAR as belonging to the same object. Information about the object was then placed in The NEO Confirmation Page. In response, J. Ticha reported observations made at the Klet Observatory that showed a faint coma (diameter 17") and a 35" tail in p.a. 226 deg, and L. Sarounova reported from the Ondrejov Observatory on a narrow tail 5' long in p.a. 135 deg and only a small coma. Observations were also reported by T. Spahr from the Catalina Sky Survey. The comet was named on IAUC 7024 [1998 October 6]. The comet is of short period, and it made a close approach to Jupiter early in 1992. Nick James was able to image it on 1998 October 14.

    Alex Gibbs discovered an 18th magnitude comet during the Catalina Sky Survey with the 0.68m Schmidt on 2015 September 30.13. He suggested that it might be a recovery of P/LONEOS-Tucker, which had been missed at its 2007 return. Other astrometrists, including Peter Birtwhistle confirmed the comet, and Gareth Williams computed a linked orbit. The correction to the predicted time of perihelion in published elements for the return was -1.9 days. [CBET 4146, MPEC 2015-T06, 2015 October 5]


    329P/LINEAR-Catalina = 2003 WC7 = 2015 T1
    LINEAR discovered a 20th magnitude object on 2003 November 18.14 which was observed on two nights. It was independently discovered by the Catalina Sky Survey on 2004 January 31.14 and posted on the NEO confirmation page. Other observers then noted a coma and tail. The object was in an 11.8 year orbit with perihelion at 1.65 au.

    An apparently asteroidal object was discovered by the LINEAR project on 2003 November 18 (observed on only two nights) and given the designation 2003 WC_7 (MPS 91151). The object was discovered independently on January 31 by the Catalina Sky Survey and then posted on the NEO Confirmation Page. As a result, it has been found to show cometary appearance on CCD exposures taken by J. Young (Table Mountain, 0.6-m reflector, Feb. 1.15 UT; very diffuse coma of mag 17.5 and diameter 5", very little central condensation, and a straight, narrow 10" tail in p.a. 345 deg) and by G. J. Garradd and R. H. McNaught (Siding Spring, 1.0-m f/8 reflector, Feb. 1.46; coma diameter 3".5 in 2".5 seeing; no obvious tail visible in five co- added 40-s frames). [IAUC 8280, 2004 February 1]

    PanSTARRS discovered what was thought to be an unknown 20th magnitude comet on October 10.53, though the discovery report did suggest that it might be a recovery of 2003 WC7 (P/LINEAR-Catalina). Further astrometry confirmed the identification. The indicated correction to the prediction by G. V. Williams on MPC 79352 is Delta(T) = +0.70 day; the indicated correction to the prediction by S. Nakano in the ICQ's 2015 Comet Handbook is Delta(T) = +0.37 day. CBET 4148, MPEC 2015-T72, 2015 October 12]. The indicated ICQ Handbook does not appear to have any functional web links and is apparently not on the internet.


    330P/Catalina = 1999 V1 = 2015 U1
    C. W. Hergenrother, Lunar and Planetary Laboratory, reported the discovery of another comet of 18th magnitude by the Catalina Sky Survey on 1999 November 5.44. [IAUC 7302, 1999 November 7] The comet was close to perihelion at 2.9 au and had a period of 16.8 years.

    Krisztian Sarneczky recovered 1999 V1 on 2015 October 22.98 with the 0.6m Schmidt at Piszkesteto station of Konkoly Observatory. Following the observation he was able to identify images from September 13. The indicated correction to the prediction by Gareth Williams on MPC 84326 is Delta(T) = -0.74 day. [CBET 4155, MPEC 2015-U49, 2015 October 24]


    331P/Gibbs = 2012 F5
    Alex Gibbs discovered a 20th magnitude comet on March 22.29 on images taken during the Mt Lemmon Survey with the 1.5m reflector. The comet has a period of around 5.2 years and was at perihelion at 2.9 au in 2010 March. Given the interval since perihelion, it may be in outburst.  It was numbered in 2016.
    332P/Ikeya-Murakami = 2010 V1 = 2015 Y2
    A visual comet was discovered by Japanese amateur observers, Kaoru Ikeya (Mori-machi, Shuchi-gun, Shizuoka-ken; 25-cm reflector at 39x; diffuse with some condensation; coma diameter 1' on November 2.831 and 2' on November 3.812) and by Shigeki Murakami (Toukamachi, Niigata-ken; 46-cm reflector at 78x; coma diameter 4' with a 2' tail in p.a. 90 deg on November 3.801; moving eastward at approximately 2'/hr). It is 47 years since the first discovery by Ikeya (1963 A1).

    The comet was magnitude 8.5 at discovery by Ikeya, and 8 the following day. It seemed to be brightening rapidly, as visual observation by Juan Jose Gonzalez on November 4.2 put it as bright as 7.6 in 10x50B. This may indicate that the comet is undergoing an outburst. This suggestion is partially confirmed by Ikeya's failure to spot the comet when he searched the discovery area on November 1.8. The coma expanded, and the comet had faded to around 12th magnitude by early December, much faster than a standard light curve would suggest.

    The orbit is elliptic, with the comet at perihelion at 1.6 au in mid October and a period of around 5.3 years, as first suggested by Hirohisa Sato. Maik Meyer noted that there were similarities with the orbit of P/2010 B2, however once the orbit of 2010 V1 became better known Hirohisa Sato was able to show that the two orbits did not converge when computed back in time.

    A paper by Masateru Ishiguro et al suggests that the outburst took place between 2010 October 31 and November 3 and was largely comprised of dust.  It was smaller than the outburst of 17P/Holmes, although the energy per unit mass was comparable.  They suggest crystallisation of amorphous water as a likely cause.

    A 21st magnitude comet discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on 2015 December 31.52, and briefly on the PCCP, was identified with 2010 V1 (P/Ikeya-Murakami).  A secondary component was also discovered.  The comet returns to perihelion in 2016 March at 1.57 au and has a period of 5.4 years.  The indicated correction to the prediction by Gareth Williams on MPEC 2013-O31 is Delta(T) = +7.0 day.  [CBET 4230, MPEC 2016-A10, 2016 January 2]  The secondary component was designated 2010 V1-B [CBET 4231, MPEC 2016-A36, 2016 January 5], though there were no reports of it at that return.  The MPEC orbit for the secondary uses 435 observations, compared to 399 for the primary, both going back to 2010 November 3.  The two orbits are slightly different.  An orbit for a  tertiary component, designated 2010 V1-C, was published on January 26 and again quoted the use of observations back to 2010.  This MPEC also gave observations of a fourth component.  An orbit for a  fifth component, designated 2010 V1-E, was published on February 5, and a sixth, 2010 V1-F on February 9; again both quoted the use of observations back to 2010.  Orbits for further components, G, H, I and J have now been published.

    Calculations by Zdenek Sekanina originally suggested that component B was the primary, and that component A separated at the last return, probably during the major outburst which began around 2010 November 1.  The tails of the two components lie in different directions, with that of component A in the orbital plane and composed of debris, whilst that of component B is closer to the anti-solar direction.  Further observations, including of a further component, D, now suggest that C is the main body as Zdenek Sekanina notes in CBET 4250 [2016 February 3].

    Z. Sekanina, Jet Propulsion Laboratory, writes that recent developments (cf. MPEC 2016-B77) suggest that the 2010 outburst had more severe consequences for the comet's evolution than to accompany a single fragmentation event.  It triggered a fragmentation process that continued over an extended period of time after the outburst (and apparently is still continuing) -- a fairly common phenomenon among split comets that is referred to as "cascading fragmentation" (e.g., Sekanina 2002, Ap.J. 566, 577).  As already pointed out on CBET 4235, fragment A is not a primary component.  Since component B was the only other fragment known by Jan. 4, it was the candidate for the primary due to its location, but not by its very diffuse appearance.  The subsequent detection of fragment C (MPEC 2016-B77), about 12"-13" east of component B on Jan. 8 and 15"-16" on Jan. 11-19, resolved this ambiguity: nucleus C is the primary, the presumably most-massive piece -- though barely active until several days ago -- of the pre-outburst parent comet, unless yet another persistent fragment should still be detected to the east of component C.  The computations suggest that companion A separated from the parent most probably in early November 2012 (with an uncertainty of +/- 2 months). at a rate of 0.36 +/- 0.04 m/s, and was subjected to a differential nongravitational deceleration of 5.2 +/- 0.6 units of 10^{-5} the solar gravitational acceleration.  This solution fits the 12 most consistent offsets of A from C between Jan. 8 and 29 moderately better than a solution forcing the fragmentation time to coincide with the time of the 2010 outburst; it is suggested that component A should survive beyond the 2016 perihelion.  The histories of companions B (probably a cluster of sub-fragments) and D cannot as yet be determined with confidence, except that these objects are likely to be more recent and less massive products of the fragmentation process than companion A.  For companion B, a very tentative solution, based only on the observations Jan. 11-29, suggests that it may have split off in the second half of 2013 or the first half of 2014.  The observations of B from Jan. 8 leave systematic residuals of 2" to 4" from this solution, and a more recent origin of B is plausible.  It is possible that the Jan. 8 astrometric positions of B refer instead to D, in which case component D would have separated only in mid-October 2015, some 150 days before perihelion and, being subjected to a deceleration of about 25 units, would be a short-lived fragment. 

    The comet is one of those known to have undergone nuclear splitting according to the list of Marcos & Marcos [Dynamically correlated minor bodies in the outer solar system, MNRAS, 474, 838, 2018 February]. They consider that the multiple fragments are linked to 2010 B2 (P/WISE). David Jewitt notes  that the nucleus has a diameter of less than 280m and likely suffers from rotational instability as it has a rotation period of around 2 hours.


    333P/LINEAR = 2007 VA85
    This highly unusual object was discovered by LINEAR with the 1.0m reflector on 2007 November 4.09.  [MPEC 2007-V73, 2007 November 9, 5-day orbit]. It has a retrograde orbit with a period of 8.6 years and perihelion was at 1.10 au at the end of 2007 July.  In the current orbit it can approach to within 0.25 au of Jupiter and 0.17 au of the Earth. The object has the shortest known retrograde orbit and showed no sign of cometary activity at the 2007 return.

    Cometary activity was detected at the 2016 return, though the comet has not yet been given a designation for this return.  Jose Gonzalez observed it in early March at 11th magnitude, considerably brighter than expected.

    4 observation received so far suggest a preliminary  uncorrected light curve of m = 10.6 + 5 log d + [20] log r .  


    334P/NEAT = 2001 F1 = 2016 A4
    E. F. Helin, S. Pravdo, and K. Lawrence, Jet Propulsion Laboratory, reported the discovery of a mag 20 comet with a faint tail about 40" long toward the west-northwest on CCD images taken with the NEAT 1.2-m reflector at Haleakala on 2001 March 24.42. Additional observations, together with orbital elements (T = 2001 Jan. 21, q = 4.3 AU, i = 19 deg, P = 15.4 yr) by B. G. Marsden, were given on MPEC 2001-F51. The object appeared diffuse on March 28.5 UT CCD images taken by G. J. Garradd, Loomberah, N.S.W. (0.45-m f/5.4 reflector). CCD observations by M. Tichy and M. Kocer at Klet (0.57-m f/5.2 reflector) on March 29.0 show a diffuse 10" coma. P. G. Comba, Prescott, AZ, reports that CCD images taken with a 0.46-m f/4.5 reflector on March 29.3 show a tail in p.a. 285 deg. [IAUC 7604, 2001 March 29]

    The comet was independently recovered at the Piszkesteto Station of Konkoly Observatory on 2016 January 7.90 and at the European Space Agency's Optical Ground Station, Tenerife on January 10.10. [CBET 4237, MPEC 2016-A105, 2016 January 11] The indicated correction to the prediction by S. Nakano in the ICQ's 2014 Comet Handbook is Delta(T) = -0.36 day.


    335P/Gibbs = 2008 Y2 = 2016 A9
    Alex R Gibbs discovered an 18th magnitude comet during the Catalina Sky Survey with the 0.68m Schmidt on 2008 December 31.37. Several observers confirmed the cometary nature. The comet was at perihelion at 1.6 au in late January and has a period of 6.8 years.

    The comet was recovered at the European Space Agency's Optical Ground Station, Tenerife on 2016 January 10.26. [CBET 4253, MPEC 2016-C42, 2016 February 5] The comet was close to the predicted orbit.


    336P/McNaught = 2006 G1 = 2016 B2
    Rob McNaught discovered another comet, during the course of the Siding Spring Survey, on 2006 April 5.70. The object was 18th magnitude and reached perihelion at 2.6 au in mid August. Further observations confirmed that it was a short period comet, with period of 11 years.

    Gareth Williams found astrometry of 2006 G1 in PanSTARRS data from 2016 January 18.57 and February 14. The comet reaches perihelion 0.1 days earlier than predicted. [CBET 4258, MPEC 2016-C201, 2016 February 15] (Note the very large number of MPECs issued in the first half of February !)


    337P/WISE = 2010 N1 = 2016 GE216
    A comet was discovered in images from the the Wide-field Infrared Survey Explorer (WISE) satellite on 2010 July 5.48. The comet showed a coma and tail. The comet was at perihelion at 1.5 au in 2010 August and has a period of 5.7 years.

    An apparently asteroidal object of 21st magnitude was discovered by PanSTARRS on 2016 April 10.58. It was linked to earlier observations and given a minor planet designation. Further PanSTARRS images taken in early June suggested that it was likely to be a comet. After their report had been received by the MPC, the MPC received a report from Erwin Schwab on the recovery of 2010 N1 (P/WISE) and he later noted the identity with the asteroid. The indicated correction to the prediction by S. Nakano for P/2010 N1 is Delta(T) = -0.65 day. [CBET 4283, MPEC 2016-L36, 2016 June 5] The comet is at perihelion at 1.65 au in 2016 July and now has a period of 6.0 years. It made a close (0.52 au) approach to Jupiter in 2013 June, which increased the perihelion distance from 1.49 au to its current value and also slightly lengthened the period.


    338P/McNaught = 2008 J3 = 2016 N1
    Rob McNaught discovered an 18th magnitude comet on 2008 May 10.69 on CCD images taken with the 0.5-m Uppsala Schmidt telescope at Siding Spring Observatory. The comet was at perihelion at 2.29 au in mid March 2009 and has a period of 7.7 years.

    The comet was recovered at the European Space Agency Optical Ground Station with the 1.0m reflector on 2016 July 2.18. It reaches perihelion 0.8 days earlier than predicted. [CBET 4288, MPEC 2016-N12, 2016 July 3/4]


    339P/Gibbs = 2009 K1 = 2016 M2
    Alex Gibbs discovered a 19th magnitude comet on survey images taken with the Mt Lemmon 1.5-m reflector on 2009 May 16.15. The preliminary orbit gave perihelion at 1.5 au in mid June, but it had a small inclination and was likely to be periodic. Further observations confirmed the short period orbit, and both the CBAT and Hirohiso Sato computed orbits. Perihelion was at 1.3 au in late June and the period around 7.1 years.

    Hirohisa Sato recovered the comet in images taken with the 0.5m iTelescope at Siding Spring on 2016 June 29.35. It reaches perihelion 0.2 days earlier than predicted. [CBET 4287, MPEC 2016-N13, 2016 July 3/4]


    340P/Boattini = 2008 T1 = 2016 N2
    Andrea Boattini discovered an 18th magnitude comet with the Mt Lemmon 1.5-m reflector on 2008 October 1.35. Several observers confirmed the cometary nature, including Peter Birtwhistle and Rolando Ligustri Prediscovery Spacewatch images were found from September 2 and 21. The comet was at perihelion at 3.0 au in late February and has a period of 8.7 years. Brian Marsden noted that the comet made a close approach to Jupiter in 2003 April, with a minimum distance 0.03 au. Further calculations by Hirohisa Sato and others show that it approached to 0.0185 au of Jupiter on 2003 April 4. Prior to the encounter the comet had perihelion at 6.2 au and a period of 22 years.

    A 20th magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on 2016 July 4.50. R Weyrk of the PanSTARRS team suggested that it might be an accidental recovery of 2008 T1 and this was confirmed by Gareth Williams. The comet reaches perihelion 0.3 days later than predicted. [CBET 4289, MPEC 2016-N27, 2016 July 5]


    341P/Gibbs = 2007 R3 = 2016 N3
    Alex Gibbs discovered a 19th magnitude comet on 2007 September 14.29 in images taken during the Catalina Sky Survey with the 0.68m Schmidt. The cometary nature was confirmed following posting on the NEOCP. The comet has a period of around 8.9 years and was at perihelion at 2.5 au in 2007 July.

    Brian Marsden noted on MPEC 2007-V52 [2007 November 6] that further [astrometric] observations of this comet were desirable.

    An 18th magnitude comet discovered during the Catalina Sky Survey with the 0.68-m Schmidt on 2016 July 15.45 was found to be the first observed return of 2007 R3. The comet reaches perihelion 0.48 days earlier than predicted.


    342P/SOHO = 2000 O3 = 2005 W4 = 2011 E1 = 2016 N5
    Jonathan Shanklin discovered another comet at 10:45 (UT) on July 31. He reported:
    I had given a lecture in the centre of Cambridge and didn't get into the office until after 10:00 (11:00 BST). First I checked the emails, including several Antarctic ones which had data that needed processing. Then I had a look at various web pages, including the latest MPECs, finally I had a look at the SOHO real time movies. I first looked at C2; there were no obvious Kreutz objects but I noted something that appeared to be moving opposite to the stars. I quickly found that it was moving consistently and emailed Doug and the group with details of the possible object. I then checked C3 in case it was visible and downloaded the real-time gif images to measure the positions. I found that it came into view at 21:30 on July 30 and was visible until 03:30 on July 31, moving horizontally from right to left just above the level of the occulting disc and below the beehive cluster. At its brightest (00:06) it was around 7th mag. I think the biggest surprise is that no-one else had picked up this object! Subsequently the comet came into view again, on images from 05:54 till after 12:00. The apparent fading around 03:30 may be due to phase effects playing a part. If it was then between us and the sun it would have zero phase and be difficult to see. The phase effect partly explains why many Kreutz comets are seen during May as this is when they are on the far side of the Sun and fully illuminated.

    The orbit was finally published on MPEC 2000-Q09 [2000 August 19], after Brian Marsden returned to the USA following the IAU meeting in Manchester. It seems that the IAU had commanded all three senior members of the CBAT to attend the meeting. The comet had been at perihelion on July 30.94 at a perihelion distance of 0.054 au. Potentially observable from the ground it is at an elongation of 50 degrees in late August, though at a magnitude of near 20. The orbit shows that it passed on the far side of the sun, so phase effects do not explain the fading.

    Further to IAUC 7472, D. Hammer has provided measurements of a comet detected by the SOHO C2 and C3 instruments and found by J. D. Shanklin via the SOHO website. The reduced measurements and orbits by B. G. Marsden, together with a search ephemeris, are given on MPEC 2000-Q09. G. J. Garradd, Loomberah, N.S.W., reports that his search for this object around Aug. 21.4 UT, out to about 0.5 deg ahead of its predicted position, yielding nothing to mag about 18. [IAUC 7479, 2000 August 21]

         2000 UT           R.A. (2000) Decl.        MPEC
         July 30.221       8 21.5      +19 08       2000-Q09
    

    A comet was discovered with the SOHO LASCO coronographs by Bo Zhou. It was a sungrazing comet of the Kracht group. (IAUC 8638, 2005 December 4)

    Brian Marsden comments on MPEC 2005-X14 [2005 December 3]

    It seems likely that the Kracht-group comet C/2005 W4 is a return of C/2000 O3 (cf. MPEC 2000-Q09), a suggestion made by S. Hoenig before the observations above were available. The orbital linkage utilizes just the C2 observations (those from July 30.89596 onward in the case of C/2000 O3); although only the first three C/2005 W4 observations were obtained with C2, the residuals of the C3 observations are not systematically displaced.
    This orbit gives the comet a period of 5.3 years and perihelion at 0.054 au.

    2011 E1 was a sungrazing comet of the Kracht group discovered by Rainer Kracht in C3 images. IAUC 9201 [2011 March 21] gives an orbit by Gareth Williams linking 2011 E1 with 2000 O3 and 2005 W4. The orbital solution requires non gravitational parameters. There is a possibility that the comet might be visible to ground based telescopes during late March and early April 2011, though it would certainly be fainter than 20th magnitude.

    A Kracht group comet discovered by Worachate Boonplod in SOHO C2 imagery from July 1 was linked to 2000 O3, 2005 W4 and 2011 E1. The comet has a period of 5.3 years and shows non-gravitational motion. [MPEC 2016-P77, 2016 August 10, CBET 4308, 2016 August 26]

    The comet is one of those suspected to have undergone nuclear splitting according to the list of Marcos & Marcos [Dynamically correlated minor bodies in the outer solar system, MNRAS, 474, 838, 2018 February]. They link it to 2002 S7 (P/SOHO), which itself is linked to 1996 X3 (SOHO) and 2008 N4 (SOHO).


    343P/NEAT-LONEOS = 2003 SQ215 = 2016 P3
    An object originally reported as stellar by NEAT and LONEOS was found to show a coma by Alan Fitzsimmons et al. The period is nearly 13 years and it reached perihelion at 2.30 au in late March 2004.

    An apparently asteroidal object reported independently by the NEAT (on September 24.18) and LONEOS (on September 27.16) projects has been found to show a nonstellar appearance in individual 30-s R-band images taken by A. Fitzsimmons and C. Snodgrass, Queen's University of Belfast, and O. Hainaut, European Southern Observatory (ESO), on 2004 Jan. 19.0 UT at the ESO 3.6-m New Technology Telescope (+ SUSI-2 camera). Fitzsimmons adds that co- addition of the frames shows an asymmetric coma of total mag 20.3 extending 1".7 in p.a. 130 deg. [IAUC 8274, 2004 January 23]

    A 20th magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on August 12.48. Michael Meyer and Gareth Williams identified it with 2003 SQ215, and also found earlier PanSTARRS images from July 7, along with others taken by S. Maticic with the Crni Vrh 0.6-m f/3.3 Deltagraph on August 9. [CBET 4302, MPEC 2016-P122, 2016 August 14] The comet is returning to perihelion some 5 days earlier than previously predicted and will be at perihelion at 2.3 au in 2017 January. It has a period of 12.8 years.


    344P/Read = 2005 S3 = 2016 Q1
    Michael Read discovered a 19th mag comet on Spacewatch images taken on 2005 September 30.41. Further observations suggested a period of 11 years, with the comet at perihelion in 2006 January at 2.8 au.

    Krisztian Sarneczky recovered 2005 S3 (P/Read) with the 0.6m Schmidt at Piszkesteto Station of Konkoly Observatory on August 27.04. [CBET 4310, MPEC 2016-Q52, 2016 August 30]. The comet returns to perihelion 0.5 days earlier than predicted.


    345P/LINEAR = 2008 SH164 = 2016 Q3
    A 19th magnitude comet discovered during the Mt Lemmon Survey with the 1.5m reflector on August 29.35 was linked to asteroid 2008 SH164 discovered by LINEAR on 2008 September 28.23. [CBET 4312, MPEC 2016-Q54, 2016 August 30] The comet was at perihelion at 3.2 au in 2016 July and has a period of around 8.1 years.
    346P/Catalina = 2007 T6 = 2016 R1   
    An apparently asteroidal object of 18th magnitude, found with the 0.68m Schmidt during the Catalina Sky Survey on 2007 October 13.47 and posted on the NEOCP was found to show a coma and faint tail on images taken by J W Young with the Table Mountain 0.61-m f/16 Cassegrain reflector. The comet was at perihelion at 2.2 au in 2007 August and has a period of around 9.5 years. The comet has also been identified with asteroid 2007 TU149 by S Nakano.

    The comet was recovered by Krisztian Sarneczky and P Szekely with the 0.6m Schmidt at Piszkesteto Station of Konkoly Observatory on September 1.08.  It was not given a designation on the MPEC. It returns to perihelion 0.35 days earlier than predicted. [MPEC 2016-R19, 2016 September 2, CBET 4315, 2016 September 3 ]


    347P/PanSTARRS = 2009 Q9 = 2016 SV
    A 19th magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on September 21.47, with pre-discovery images from June 20 and September 19 that were identified later. Gareth Williams then identified the comet in images from the Catalina Sky Survey from 2009 August and October. [CBET 4323, MPEC 2016-S61, 2016 September 27] The comet was at perihelion at 2.2 au in 2016 September and has a period of 6.8 years.
    348P/PanSTARRS = 2011 A5 = 2017 A2
    A 21st magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on January 2.58. It was then subsequently linked to images found in PanSTARRS and Mt Lemmon data from 2011 January, at which return it was given the designation 2011 A5. [CBET 4341, MPEC 2017-A32, 2017 Janaury 6] The comet was at perihelion at 2.2 au in 2016 June and has a period of 5.6 years.
    349P/Lemmon = 2010 EY90 = 2017 B1
    A 21st magnitude object was discovered  in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on  January 26.59.  This was quickly linked to asteroid 2010 EY90 discovered by the Mt Lemmon Survey with the 1.5m reflector on 2010 March 14.24 and with pre-discovery Mt Lemmon images from 2017 January 7.   [CBET 4348, 4349, MPEC 2017-B82, 2017 January 27] The comet is at perihelion at 2.5 au in 2017 August and has a period of 6.75 years.
    350P/McNaught = 2010 J5 = 2017 B2
    Rob McNaught discovered a 19th mag comet during the Siding Spring Survey with the 0.5-m Uppsala Schmidt telescope on 2010 May 12.70. The initial orbit promised a visual object, however this soon changed into a periodic orbit. The comet was at perihelion at 3.7 au in 2009 November and has a period of 8.3 years. The orbital eccentricity is small, with a value of 0.09.

    Jim Scotti recovered the comet with the Spacewatch 1.8m reflector on January 26.52. It returns to perihelion in 2018 January. [CBET 4352, MPEC 2017-B123, 2017 January 29]


    351P/Wiegert-PanSTARRS = 1998 U8 = 2007 R11 = 2016 P2
    A 21st magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on August 8.52, with pre-discovery images from July 9.58. [CBET 4298, MPEC 2016-P120, 2016 August 14] The comet was at perihelion at 3.1 au in 2015 November and has a period of 9.3 years.

    Further observations allowed linkage with an asteroid discovered by P A Wiegert with the 3.6m CFHT on 2007 September 14.27, and with an object in images from LONEOS in 1998 October.


    352P/Skiff = 2000 S1 = 2017 L1
    B. W. Koehn, Lowell Observatory, reported the discovery by Brian A. Skiff of a comet on images from 2000 September 24.30 taken in the course of the LONEOS program. [IAUC 7496, 2000 September 25] Prediscovery observations made by LINEAR on 2000 August 26, together with additional astrometry on September 26, are given on MPEC 2000-S60 and showed that the comet was periodic with a period of 17.1 years. [IAUC 7497, 2000 September 27] The comet was reported as around 15th mag, but was brighter visually.

    H Sato recovered 2000 S1 (P/Skiff) on June 5.81 using the 0.51m i-Telescope at Siding Spring. The indicated correction to the prediction by S. Nakano in the ICQ's 2017 Comet Handbook is Delta(T) = -2.64 days. [CBET 4402, MPEC 2017-L51, 2017 June 6]


    353P/McNaught = 2009 S2 = 2017 M1
    Rob McNaught discovered a 19th magnitude comet on images taken during the Siding Spring Survey with the 0.5-m Uppsala Schmidt on 2009 September 20.68. The preliminary orbit allowed prediscovery observations from August 3 to be located. The comet was at perihelion at 2.2 au in June and has a period of around 8.5 years.

    Krisztian Sarneczky and R. Konyves-Toth recovered 2009 S2 (P/McNaught) using the 0.60-m Schmidt telescope at the Piszkesteto Station of Konkoly Observatory. The indicated correction to the prediction by S. Nakano in the ICQ's 2017 Comet Handbook (p. H13) is Delta(T) = -0.06 day. [CBET 4404, MPEC 2017-M28, 2017 June 20]


    354P/LINEAR = 2010 A2 = 2017 B5
    An apparently asteroidal object of 20th magnitude discovered by LINEAR with the 1.0-m reflector on 2010 January 6.27 was found to show a cometary appearance by other astrometrists, notably Peter Birtwhistle, but whilst it has a tail, there is no distinctive central condensation. The comet has an exceedingly short period of 3.5 years and was at perihelion at 2.0 au in 2009 December. The orbit is typical of a main belt asteroid and it may be a small (less than 500 metres) carbonaceous type object.

    Javier Licandro, G. P. Tozzi, and Tiina Liimets note:

    On January 14 we obtained images of this object using the Nordic Optical Telescope in La Palma, and on Jan 15 we made the following report to the CBAT:"J. Licandro (Instituto de Astrofísica de Canarias, Spain), G. P. Tozzi (INAF, O. di Arcetri), and Tiina Liimets (Nordic Optical Telescope, NOT, Spain & Tartu Obs., Estonia) report the presence of an object, probably an asteroid, 2 arcsec to the East of P/2010 A2 (LINEAR). Six images of 5 minute exposure time each were obtained on Jan. 14 using ALFOSC (Andalucia Faint Object Spectrograph and Camera) on the 2.6m NOT telescope at the "Roque de los Muchachos" Observatory (La Palma, Canary Islands, Spain). Four images were obtained in the R band and two in the V band, starting 22:41 ending 23:39 UT, in non-photometric but very good seeing (0.6 arcsec) conditions. The asteroid moves in the same direction and at the same rate as the comet. In adition, the P/2010 A2 (LINEAR) image does not show any central condensation and looks like a "dust swarm". It is 4 arcmin long and only about 5 arcsec wide (177.000 and 3700 km respectively at the comet distance) with a PA=277 degrees. These observations suggest a connection between the asteroid and the dust swarm. A short lived event, such as a collision, may have produced the observed dust ejecta.". Next night, Jan. 16, the object was observed with the 10.4m GTC telescope and we made the following report "J. Licandro (Instituto de Astrofísica de Canarias, IAC, Spain), A. Cabrera-Lavers and G. Gómez (IAC & GTC Project Office, Spain) confirms the detection of an object, probably an asteroid, abut 2 arcsec to the East of P/2010 A2 (LINEAR), reported on Jan. 15 by Licandro et al. , on a series of 30s images obtained with the OSIRIS instrument on the 10.4m Gran Telescopio Canarias (GTC) at the "Roque de los Muchachos" Observatory (La Palma, Canary Islands, Spain), on Jan 16, starting 1:41 and ending 3:11 UT. A total of 54 images 30s exp. time each were obtained, 24 with the r, 18 with the i and 12 with the g sloan filters respectively. The object is visible in all images."

    Following a suggestion by myself, Darryl Sergison imaged the comet with the 2.0-m Faulkes Telescope. Richard Miles reported:

    A few images were taken of P/2010 A2 by Darryl Sergison using the 2.0-m Faulkes Telescope North on January 15 and these showed no evidence of condensations within the elongated coma however the seeing was not particularly good at the time. Another attempt stacking a dozen or so images when subarcsecond seeing is present will be necessary.
    The Hubble Space Telescope took a spectacular image of the object on January 29. Z. Sekanina, Jet Propulsion Laboratory, writes that the orientations of the tail of this comet reported from the observations made between January 7 and 16 (IAUC 9105, 9109; CBET 2134) suggest its formation between January and August 2009. Because of the edge-on projection (with the earth only 2 to 3 degrees below the comet's orbital plane) it is not possible to decide whether the tail is a product of one or more brief emission events or continuous activity over a period of time. From the tail's length, the maximum solar radiation pressure acceleration exerted on the dust is estimated at about 0.1 percent of the solar gravitational acceleration, which implies that the smallest dust particles in the tail are about 1 mm in diameter (at an assumed density of 1 g/cm^3).
    From the width of the tail, a lower limit on the normal component of the particle velocity is about 0.1 m/s. An improved estimate can be determined from the tail width around the time of the earth's crossing the orbital plane on 2010 February 9. [IAUC 9110, 2010 January 25]

    David Jewitt et al have a paper on the object, which is to appear in the Astronomical Journal. They conclude that it was an asteroid, which suffered a collision, and that such events should be relatively common, though generally below the detetection threshold of surveys such as LINEAR.

    On 2013 June 3 the WIYN Observatory put out a press release describing how they had observed a tail of at least 15' using their new One Degree Imager (which currently does 30').  This apparent length corresponds to a real length of about 1 million km.

    Brian Marsden noted on MPEC 2010-F69 [2010 March 23] that further [astrometric] observations of this comet were desirable.

    2010 A2 (P/LINEAR) was recovered as an apparently asteroidal object via CCD images taken by Y. Kim with the 8.1-m "Gemini North" telescope at Mauna Kea on 2017 January 26.43. The indicated correction to the prediction by S. Nakano in the ICQ's 2017 Comet Handbook is Delta(T) = +0.16 day. [CBET 4405, MPEC 2017-M38, 2017 June 21]


    355P/LINEAR-NEAT = 2004 T1 = 2017 M2
    NEAT reported a comet discovered on 2004 October 5.44, which had been reported as asteroidal by LINEAR on October 5.27. Other observers, including Peter Birtwhistle, confirmed the cometary nature of the object. It reached perihelion in early November at 1.71 au and has a period of 6.47 years. Although LINEAR reported it as 18th magnitude, NEAT gave 15th magnitude. Michael Mattiazzo reported that it was observed visually at 13.8 on October 9.62.

    K. J. Lawrence, Jet Propulsion Laboratory, reports the NEAT discovery of a comet on images taken with the Haleakala telescope, the object described as having a coma of diameter about 25", with elongated images but no obvious tail. The comet was also observed earlier on the same night (with prediscovery observations on Sept. 21) by the LINEAR team, which made no comment on the object's appearance; both "discovery" observations are tabulated below. Following posting on "The NEO Confirmation Page", numerous observers have reported on the object's cometary appearance on CCD images obtained during Oct. 5.9-6.6 UT, including M. Tichy (Klet), P. Birtwhistle (Great Shefford, U.K.), C. Jacques and E. Pimentel (Belo Horizonte, Brazil), D. T. Durig and G. A. T. Morris (Sewanee, TN), J. E. McGaha (Tucson, AZ), G. R. Jones (Tucson, AZ), and D. Higgins (Canberra, Australia). The general consensus is that there is a diffuse coma of diameter about 16"-30" and a faint, broad, fan- shaped tail about 1' wide and 4'-5' long in p.a. approximately 240-280 deg. P. Kusnirak (Ondrejov) reports the fan tail in p.a. about 290 deg and another tail about 4' long in p.a. about 240 deg. [IAUC 8416, 2004 October 6]

    2004 T1 (P/LINEAR-NEAT) was recovered with the 1.0m reflector at the European Space Agency's Optical Ground Station at Tenerife on 2017 June 21.17. The indicated correction to the prediction by B. G. Marsden on MPC 89018 is Delta(T) = -0.57 day. The 2011 return was missed because the comet was in conjunction with the sun while near perihelion. [CBET 4406, MPEC 2017-M40, 2017 June 22]


    356P/WISE = 2010 D1 = 2017 O2
    A comet was discovered in images from the the Wide-field Infrared Survey Explorer (WISE) satellite on 2010 February 17.34. The object showed a hazy coma and tail though the nuclear condensation was less pronounced than that of P/2010 B2. It was confirmed by Spacewatch observations on February 19.2. Additional images were then found in Catalina observations made on 2009 November 9 and December 10. The comet has a period of 8.5 years and was at perihelion at 2.7 au in 2009 June.

    Brian Marsden noted on MPEC 2010-H19 [2010 April 19] that further [astrometric] observations of this comet are very desirable.

    PanSTARRS discovered a 21st magnitude comet on 2017 July 30.54, which appeared on the PCCP as P10Cawe, but was soon linked to 2010 D1 (P/WISE). The indicated correction to the prediction by Gareth Williams on MPC 89019 was Delta(T) = -1.85 days [CBET 4416, MPEC 2017-P09, 2017 August 3]


    357P/Hill = 2008 T4 = 2017 Q1
    Rik Hill discovered an 18th magnitude comet on CCD images taken with the 0.68-m Catalina Schmidt telescope on 2008 October 8.39. The comet has a period of 9.4 years and was at perihelion at 2.51 au in late December.

    PanSTARRS recovered 2008 T4 with the 1.8m Ritchey-Chretien on August 18.49. There were also pre-recovery images from July 25. The indicated correction to the prediction by S. Nakano in the ICQ's 2017 Comet Handbook was Delta(T) = -0.67 day [CBET 4421, MPEC 2017-Q47, 2017 August 22/19]


    358P/PanSTARRS = 2012 T1 = 2017 O3
    Pan-STARRS discovered a 21st magnitude comet on 2012 October 6.53. Confirmation was made by astrometrists from the T3 group. Archival observations from Pan-STARRS were found from 2011 July. The comet was at perihelion at 2.4 AU in 2012 September and has a period of around 5.6 years. It is a Main Belt Comet, with a stable orbit for the period 1900 - 2100.

    On 2013 January 26 Rob Matson found images of a comet in frames taken by NEAT with the Palomar 1.2m Schmidt on 2001 December 9. This was linked to 2003 BM80, discovered by LONEOS at the Anderson Mesa station on 2003 January 31 and to 2012 T1.

    Although the comet was numbered, the MPC list as recently as 2017 July 10 did not give it a name.  It was recovered on 2017 July 1.37 with the Gemini South 8.1m reflector.  This time it was given the PanSTARRS name and the designation 2017 O3, though not linked to the originally numbered comet. [MPEC 2017-Q115, 2017 August 25] The object previously linked with the comet is now considered to be a Main-belt asteroid and has been numbered as (323137) with an additional identity with 2003 FV112. This object retains the identity 282P. The 2001 NEAT object is linked to comet 358P.


    359P/LONEOS = 2007 RS41 = 2017 Q2
    PanSTARRS discovered a 21st magnitude comet with the 1.8m Ritchey-Chretien on 2017 August 22.48. Gareth Williams then identified it with an apparently asteroidal object, 2007 RS41, found at Lowell Observatory in the course of the LONEOS project in images taken by J. J. Sanborn with the 0.59-m LONEOS Schmidt telescope on 2007 August 21.39. [CBET 4424, MPEC 2017-Q116, 2017 August 25]
    360P/WISE = 2010 P4 = 2017 S1
    Amy Mainzer, Jet Propulsion Laboratory, reported that a comet was discovered in images from the the Wide-field Infrared Survey Explorer (WISE) satellite on 2010 August 6.59. The comet showed a 150" tail. Following posting on the NEOCP, ground based observers did not note any cometary characteristics in the nearly 22nd magnitude object. The comet was at perihelion at 1.9 au in 2010 July and has a period of 7.1 years.

    The ESA Optical Ground Station at Tenerife recovered 2010 P4 with the 1.0m telescope on 2017 September 20.10. [CBET 4429, MPEC 2017-S90, 2017 September 20]


    361P/Spacewatch = 2006 UR111 = 2017 S4
    A comet discovered by PanSTARRS on 2017 September 24.29 was linked to an asteroid discovered by Spacewatch on 2006 October 19.13. It was designated as 2006 UR111 at that return. [CBET 4433, MPEC 2017-S197, 2017 September 28] The comet is at perihelion at 2.8 au in 2018 July and has a period of 11 years. It may have undergone a minor outburst, as it was 21st magnitude on September 11, and 19th magnitude on September 27.
    362P/Spacewatch = (457175) = 2008 GO98
    This Outer Main-belt (Hilda group) asteroid was discovered by Spacewatch on 2008 April 8 at Kitt Peak.

    Gareth Williams reported on MPEC 2017-N50 [2017 July 3]:

    G. J. Leonard, using the MLS 1.5-m reflector, reported a comet candidate, described as having a coma of 7"-8" diameter and a broad ~15"-long tail in P.A. ~260 deg. This object was linked by MPC automated routines with the numbered Hilda minor planet (457175). Follow-up observations by D. C. Fuls with the MLS 1.0-m reflector confirm the cometary nature: very bright coma at least 8" diameter, with a very broad 12"-long tail in P.A. 265 deg. Additional follow-up observation by Leonard show as 10" coma and a broad, diffuse 15"-long tail in P.A. ~260 deg.

    Further observations of this object are encouraged to clarify the nature of this cometary activity.

    The comet was perturbed from a Centaur type orbit by a close (0.05 au) encounter with Jupiter in 1710. The orbit was further perturbed in 2011 September, and the first perihelion since then was in 2016.


    363P/Lemmon = 2011 VJ5 = 2017 W1
    This object was discovered as an asteroid by the Mt Lemmon Survey with the 1.5m reflector on 2011 November 3.46. There was nothing particularly unusual about the preliminary orbit. Cometary characteristics were detetected by the Catalina Sky Survey on 2012 February 1.47, and the new orbit gives the comet a period of 6.2 years with perihelion at 1.5 au in 2011 December. The comet was perturbed into its present orbit by encounters to within 0.22 au of Jupiter in 1949 and 2009, and the current perihelion distance is the smallest between 1900 and 2100. Another encounter with Jupiter to 0.45 au in 2020 will push out the perihelion distance to 1.7 au.

    Paplo Ruiz recovered 2011 VJ5 (P/Lemmon) on November 19.13 using a 1.0-m f/4.4 reflector at the European Space Agency's Optical Ground Station, Tenerife, Spain. It was confirmed the following night, and then additional images from October and earlier in November were found by Gareth Williams. The indicated correction to the prediction by S. Nakano is Delta(T) = +1.04 day. [CBET 4455, MPEC 2017-W73, 2017 November 19/20].


    364P/PanSTARRS = 2013 CU129 = 2018 A2
    An asteroid was discovered by Pan-STARRS 1 with the 1.8m R-C telescope on 2013 February 13.32. Subsequent observations in 2013 June showed cometary features. [MPEC 2013-L64, 2013 June 13]. The comet has a period of 4.9 years with perihelion at 0.80 au in 2013 August. It makes relatively frequent approaches to both Jupiter and the Earth, with approaches to our planet in 2018 (0.45 au) and 2023 (0.12 au).

    2 CCD and visual observations received at the 2013 return suggest a preliminary aperture corrected light curve of m = 15.2 + 5 log d + [10] log r

    Erwin Schwab reported the recovery of 2013 CU129 to the Central Bureau in remotely obtained images that he had taken with the 0.8m Schmidt at Calar Alto, Spain, on January 16.92. In the meantime Gareth Williams of the Minor Planet Centre had identified the comet in incidental astrometry from Mt Lemmon on January 12.38. As is becomming commonplace, two CBETs were required to correctly announce the recovery. [CBET 4474, 4475, MPEC 2018-B14, 2018 January 17] The indicated correction to the prediction by S. Nakano in the ICQ's 2018 Comet Handbook is Delta(T) = +0.02 day.


    365P/PanSTARRS = 2011 WG113 = 2017 U6
    An apparently asteroidal object of 21st magnitude was discovered in PanSTARRS images taken with the 1.8m Ritchey-Chretien on 2011 November 24.29 and also observed on 2011 December 2. This was designated 2011 WG113. The object was re-discovered by PanSTARRS on 2017 October 21.43, still appearing as asteroidal. Subsequent observations in 2018 February by the Catalina and Mt Lemmon telescopes showed a diffuse coma and tail, so it was designated as 2017 U6. [CBET 4490, MPEC 2017-D88, 2018 February 27] The CBET is likely to be replaced by a follow-up, as there are grammatical errors. The comet was at perihelion at 1.4 au in 2018 February. It has a period of 5.7 years and JPL classify it as a Jupiter-family comet.
    366P/Spacewatch = 2005 JN = 2018 F2
    An apparently asteroidal object of 20th magnitude found by Spacewatch on 2005 May 3.20 was found to show cometary features. It reached perihelion at 2.3 au in June 2005 and has a period of 6.5 years.

    2005 JN was recovered with the 1.0m f/4.4 reflector at the ESA Optical Ground Station at Tenerife on 2018 March 17.18. It was 20th magnitude.


    367P/Catalina = 2011 CR42 = 2018 H1
    This main belt asteroid was discovered by the Catalina Sky Survey with the 0.68m Schmidt on 2011 February 10.47 and was followed until June. Hints of cometary activity were given on a CBET that was issued on 2011 September 23. It was at perihelion at 2.5 au in 2011 November, but was then poorly placed for observation.

    Cometary activity was finally confirmed in 2013, when it was observed from August to October. [MPEC 2013-U85, 2013 October 30]. The comet has a period of 6.6 years.

    Erwin Schwab recovered the comet during remote observations with the Calar Alto 0.8m Schmidt on 2018 April 17.01. No tail or coma was detected in total exposures of 600s.


    368P/NEAT = 2005 R1 = 2018 L3
    NEAT discovered a cometary object of 18th magnitude on images taken on 2005 September 2.43. The comet reached perihelion at 2.05 AU in early October. It is in an eliptical orbit with a period of 13 years. It brightened a little, reaching 17th magnitude in October.

    The comet was recovered in images taken at the European Space Agency's Optical Ground Station at Teneriffe with the 1.0m reflector on June 13.19. It was 19th magnitude. The indicated correction to the prediction by S. Nakano in the ICQ's 2018 Comet Handbook is Delta(T) = -0.07 day. [CBET 4526, MPEC 2018-L76, 2018 June 14]


    369P/Hill = 2010 A1 = 2018 P1
    Rik Hill discovered an 18th magnitude comet on 2010 January 6.46 during the Catalina Sky Survey with the 0.68m Schmidt. Confirming images were taken by Peter Birtwhistle amongst others. The comet has a period of around 9 years, and was at perihelion at 1.9 au in 2009 August.

    Erwin Schwab reported the recovery of 2010 A1 in images taken with the 1.0m reflector at the European Space Agency's Optical Ground Station at Teneriffe on August 10.18. [CBET 4538, MPEC 2018-P80, 2018 August 13] The MPEC says "The 2018 prediction by B. G. Marsden on MPC 94681 required a correction in T of +0.39 days." A better phrasing might be "The prediction for the 2018 return by B. G. Marsden on MPC 94681 required a correction in T of +0.39 days."


    370P/NEAT = 2001 T3 = 2018 P2
    K. Lawrence, S. Pravdo, and E. F. Helin, Jet Propulsion Laboratory, reported the discovery on 2001 October 14.45 by the NEAT program of an 18th mag comet with a faint coma on CCD images taken with the Palomar 1.2-m Schmidt telescope. The object also appeared cometary on CCD images taken by P. Pravec and P. Kusnirak at Ondrejov (moderately condensed coma of diameter 0'.2 on 2001 October 14.9 UT) and by J. Ticha, M. Tichy, and P. Jelinek at Klet (diffuse 11" coma on October 14.9; 10" coma and m_1 = 17.0 on October 15.8). [IAUC 7733, 2001 October 15] The comet is in a 16 year periodic orbit with perihelion at 2.5 au.

    Erwin Schwab reported the recovery of 2001 T3 in images taken with the 1.0m reflector at the European Space Agency's Optical Ground Station at Teneriffe on August 10.20. [CBET 4539, MPEC 2018-P81, 2018 August 13] The 2018 prediction by the Gareth Williams on MPC 94679 required a correction in T of -1.16 days.


    371P/LINEAR-Skiff = 2001 R6 = 2018 R1
    B. A. Skiff, Lowell Observatory, reported his discovery of a 17th mag comet on CCD images taken by him with the LONEOS telescope on 2001 Sept. 25.32. The object showed a moderately condensed 15" coma and a broad tail about 25" toward the west-northwest. T. B. Spahr identified this comet with an object observed on two nights (Sept. 11 and 16, previously linked; m_2 = 19.4-20.0) and reported as asteroidal in appearance by LINEAR; subsequently LINEAR observations from Aug. 19 were also identified. J. G. Ries reported that CCD images obtained with the 0.76-m reflector at McDonald Observatory on Sept. 27.3 UT also showed this object to be diffuse. [IAUC 7723, 2001 September 27] The comet has a period of 8.3 years and a perihelion distance of 2.1 au.

    Erwin Schwab reported his recovery of 2001 R6 in images taken with the 1.0m reflector at the European Space Agency's Optical Ground Station at Teneriffe on September 7.09. The comet was not recovered at the 2010 return. The correction to T compared to the 2013 MPEC prediction is +0.36 days. [CBET 4552, MPEC 2018-R59, 2018 September 8]


    372P/McNaught = 2008 O2 = 2018 P6
    Rob McNaught discovered an 18th magnitude comet on 2008 July 28.69 on CCD images taken with the 0.5-m Uppsala Schmidt telescope at Siding Spring Observatory. Although the initial parabolic orbit looked promising for visual observation, as more observations accumulated it became clear that it was a periodic comet with perihelion at 3.8 au in 2009 April. The period is around 9.5 years.

    Brian Marsden noted on MPEC 2008-Q07 [2008 August 18] that the orbit indicates a very close approach to Jupiter (to 0.1 au) in 2003 and that the previous perihelion distance was around 5.8 au.

    Gareth Williams recovered 2008 O2 in astrometric data submitted by PanSTARRS (PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on August 8.50) and the Gaia-GBOT team (images taken with the 2.6m Ritchey-Chretien at Cerro Paranal on September 6.13). The comet was apparently stellar in appearance. [CBET 4554, MPEC 2018-S01, 2018 September 16] The prediction for the return by Gareth Williams on MPC 94681 required a correction in T of -0.52 days.


    373P/Rinner = 2011 W2 = 2018 R2
    Amateur observer Claudine Rinner discovered a comet from Oukaimeden Observatory, near Marrakech, Morocco on 2011 November 28.13 on CCD images taken by herself and Michel Ory with the 0.5-m f/3 reflector. The comet was at perihelion at 2.3 au in 2011 November and has a period of around 7.4 years.

    Jean-Francois Soulier (0.3m Newtonian f/4 reflector at Maisoncelles, September 9.03) and Krisztian Sarneczky (0.6m Schmidt at the University of Szeged, Piszkesteto Station (Konkoly), September 14.11) independently recovered 2011 W2. The prediction for the return by Gareth Williams on MPC 102105 required a correction to T of -0.43 days. [CBET 455x, MPEC 2018-S03, 2018 September 16]


    374P/Larson = 2007 V1 = 2018 S1
    Steve Larson discovered a 17th magnitude comet on 2007 November 8.31 in images taken during the Catalina Sky Survey with the 0.68m Schmidt. The comet has a period of around 11 years and perihelion was at 2.7 au in 2007 December.

    Krisztian Sarneczky and Robert Szakats (0.6m Schmidt at the University of Szeged, Piszkesteto Station (Konkoly)) recovered 2007 V1 on September 18.00. The prediction for the return by Gareth Williams on MPC 102104 required a correction to T of -1.17 days. [CBET 4558, MPEC 2018-S31, 2018 September 18]


    375P/Hill = 2006 D1 = 2018 T1
    BAA Member Rik Hill discovered another comet during the course of the Catalina Sky Survey. It was a faint 20th magnitude object in a periodic orbit of 13 years with perihelion at 1.89 au.

    Krisztian Sarneczky (0.6m Schmidt and 1.02m Ritchey-Chretien at the University of Szeged, Piszkesteto Station (Konkoly)) recovered 2006 D1 on 2018 October 5.10. The prediction for the return by Gareth Williams on MPC 94682 required a correction to T of -0.22 days. [CBET 4560, MPEC 2018-T62, 2018 October 6]


    376P/LONEOS = 2005 GF8 = 2018 X1
    An 18th magnitude asteroid discovered by LONEOS on 2005 April 2.43 was found to show a coma by amongst others, Peter Birtwhistle. The object has perihelion at 2.8 au and a period of 14.2 years.

    Erwin Schwab reported the recovery of 2005 GF8 in images taken with the 1.0m reflector at the European Space Agency's Optical Ground Station at Teneriffe on 2018 December 4.25. The correction to the prediction by B. G. Marsden on MPC 54823 is delta-T = -1.4 days. [CBET 4581, MPEC 2018-X49, 2018 December 6]


    377P/Scotti = 2003 L1 = 2019 E1
    Jim Scotti discovered this faint comet in Spacewatch data on 2003 June 4.21. Further prediscovery images were found in Palomar NEAT data from 2002 April. The comet was three months past perihelion, which was at 5.0 au. The period is 17.3 years.

    J. V. Scotti, Lunar and Planetary Laboratory, University of Arizona, reports the discovery of a 20th mag comet on CCD images taken with the Spacewatch 0.9-m f/3 reflector at Kitt Peak on June 4.21, showing a coma of diameter 6" and a faint tail about 0'.62 long in p.a. 273 deg. Images taken by A. S. Descour on June 5.3 with the 1.8-m f/2.7 Spacewatch reflector also show a tail, and June 7.2 images by Scotti with the larger instrument show the tail 0'.30 long in p.a. 273 deg. [IAUC 8145, 2003 June 7]

    Clearly diffuse NEAT images of this comet, taken with the Palomar 1.2-m Schmidt telescope on three nights in 2002 April, were identified and measured by M. Meyer. Additional astrometry and the orbital elements (MPEC 2003-M21) confirm the suspicion (cf. IAUC 8145) that this is a short-period comet. [IAUC 8153, 2003 June 19]

    Erwin Schwab reported his recovery of 2003 L1 in images taken with the 1.0m reflector at the European Space Agency's Optical Ground Station at Teneriffe on 2019 March 9.11. The correction to T compared to the 2017 prediction on MPC 105247 is -0.39 days. [CBET 4612, MPEC 2019-E80, 2019 March 10]


    378P/McNaught = 2005 Y2 = 2019 E2
    Rob McNaught discovered another comet with the 0.5-m Uppsala Schmidt during the Siding Spring Survey on 2005 December 30.46. It was 19th magnitude at discovery. It was at perihelion at 3.4 au in late December 2004 and has a period of 16 years.

    Erwin Schwab reported his recovery of 2005 Y2 in images taken with the 1.0m reflector at the European Space Agency's Optical Ground Station at Teneriffe on 2019 March 10.14. The correction to T compared to the 2011 prediction on MPC 75706 is +0.04 days. [CBET 4613, MPEC 2019-F27, 2019 March 18]


    379P/Spacewatch = 2006 F4 = 2019 D2
    A 20th mag comet was found on Spacewatch images taken on 2006 March 26.36 with the 0.9-m reflector by R S McMillan and M T Read. Perihelion was at 2.34 au in early May 2006 and it has a period of 6.6 years.

    This comet, missed at its 2012 apparition, was recovered by Gareth Williams in incidental astrometry reported by the Mount Lemmon Survey from February 28.38, which was then linked to a single-night detection on the NEOCP. R. Weryk (F51) also suggested the linkage when he reported that the same NEOCP object had a FWHM of ~1".8 (compared to 1".15 +/- 0".04 for nearby stars) and a ~4" tail to the east. The indicated delta-T correction to the prediction, by B. G. Marsden, on MPC 56954 is -1.29 days (in 2012, the correction was -0.61 days). [CBET 4616, MPEC 2019-G21, 2019 April 3].


    380P/PanSTARRS = 2011 O2 = 2019 G1
    A 23rd magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on April 3.51. Once the provisional orbit was better known it was possible for the PanSTARRS team to find prediscovery PanSTARRS observations from 2019 February, 2018 (when it was stellar) and 2011 (also stellar). There were also Mt Lemmon observations from 2019 March. With these observations, Gareth Williams then found further images from 2009 by Spacewatch and Purple Mountain Observatory. The comet was designated as 2011 O2 for the 2009 return. It was placed on the PCCP as P10MA2B.  [CBET 4610, MPEC 2019-G123, 2019 April 9]  The comet has a period of 9.6 years and was at perihelion at 3.0 au in 2009 October and 2019 June.
    381P/LINEAR-Spacewatch = 2000 S4 = 2019 K2
    Tom Gehrels reported his discovery of a faint (20th mag) comet on 2000 October 2.15 images taken with the Spacewatch telescope at Kitt Peak, noting it to have a 4" tail in p.a. 170 deg. Tim B. Spahr, Minor Planet Center, linked it to an asteroidal object observed on 2000 September 23 and 26 reported earlier by LINEAR and then found LINEAR observations made on 2000 September 1. At the request of Gehrels, P. Massey obtained images of the object in subarcsecond seeing with the 4-m Mayall Telescope at Kitt Peak on October 3.25, showing the comet to have a fan-shaped structure 4" long spanning p.a. 0-80 deg. [IAUC 7502, 2000 October 3] The comet was close to perihelion at 2.3 au and has a period of around 19 years.

    The IAU Committee on Small Bodies Nomenclature gave to comet P/2000 S4 (cf. IAUC 7502) the name LINEAR-Spacewatch. [IAUC 7553, 2000 December 31]

    Gareth Williams found images of 2000 S4 (P/LINEAR-Spacewatch) in incidental astrometry submitted by PanSTARRS and the Mt Lemmon Survey taken on 2019 May 29.57 (PanSTARRS) and 2019 June 1.44 (Mt Lemmon). The indicated delta-T correction to the prediction on MPC 102107 is +0.25 days. [CBET 4633, MPEC 2019-L11, 2019 June 2/3]


    382P/Larson = 2007 R1 = 2019 K3
    Steve Larson discovered an 18th magnitude comet on 2007 September 4.37 in images taken during the Mt Lemmon survey with the 1.5m reflector. The comet has a period of around 15 years and perihelion was at 4.4 au in 2007 August.

    Gareth Williams found images of the comet in incidental astrometry submitted by PanSTARRS taken on 2019 May 31.45. Erwin Schwab also reported the recovery in images taken with the 0.8m Schmidt at Calar Alto, Spain on May 29.09. The indicated delta-T correction to the prediction on MPC 75514 is -0.08 days. [CBET 4635, MPEC 2019-L42, 2019 June 3/4]


    383P/Christensen = 2006 S1 = 2019 M1
    Eric Christensen discovered a 17th magnitude comet on 2006 September 16.25 during the course of the Catalina Sky Survey with the 0.68-m Schmidt telescope. It was at perihelion at 1.4 au at the end of August and has a period of 6.5 years.

    Krisztian Sarneczky recovered 2006 S1 with the 0.6m Schmidt at the University of Szeged, Piszkesteto Station (Konkoly) on June 25.90. It was 20th magnitude. The prediction for the return by Brian Marsden on MPC 102108 required a correction to T of +0.71 days, which corresponds to about half a degree from the expected position. [MPEC 2019-N62, 2019 July 5, CBET 4649, July 6]. The MPEC did not give a designation, but this was given on the CBET. The comet was missed at the 2013 return.


    384P/Kowalski = 2014 U2 = 2019 O1
    Richard Kowalski discovered an 18th magnitude comet on 2014 October 25.38 in images taken during the Catalina Sky Survey with the 0.68m Schmidt. Pre-discovery CSS images from October 18.35 were quickly found and other imagers confirmed the discovery. [CBET 4006, MPEC 2014-U97, 2014 October 27] The comet has a period of around 5 years with perihelion at 1.2 au and was just past perihelion.  It is intrinsically very faint, but was discovered during a relatively good return when it was only 0.4 au from Earth; the MOID is 0.18 au.  An approach to within 1.4 au of Jupiter in 2017 September reduced the perihelion distance to 1.1 au in 2019 and it will pass 0.28 au from us in September.  In 1909 it passed 0.065 au from Mars.

    Hirohisa Sato recovered 2014 U2 in images taken with an iTelescope 0.51-m f/6.8 astrograph at Siding Spring, NSW on July 27.81. The indicated delta-T correction to the prediction on MPC 102108 is -0.02 days. [CBET 4654, MPEC 2019-O84, 2019 July 28]


    385P/Hill = 2010 U2 = 2019 P1
    Rik Hill discovered an 18th magnitude comet on Catalina 0.68-m Schmidt telescope CCD images on 2010 October 17.32. It was confirmed following posting on the NEOCP. The comet was at perihelion in 2010 November at 2.6 au and has a period of 8.8 years.

    Krisztian Sarneczky recovered 2010 U2 with the 0.6m Schmidt at the University of Szeged, Piszkesteto Station (Konkoly) on August 2.05, with confirming images on the 7th. It was 21st magnitude. The indicated delta-T correcton to the prediction, by Gareth Williams, on MPC 102107 is -0.47 days. [MPEC 2019-P61, CBET 46xx, 2019 August 9].


    386P/PanSTARRS = 2011 U1
    Pan-STARRS discovered a 21st magnitude comet on 2011 October 23.45. It was at perihelion at 2.4 au in 2012 June and has a period of around 8.1 years.  Maik Meyer located NEAT images of the comet from 2004 February, so the comet should have been numbered once a linked orbit was computed.  An orbit based on observations from 2004 to 2012 was published in MPC 78186 in 2012 February. The MPC might have been waiting on additional Spacewatch images before numbering the comet, or waiting for a further return.

    The comet was finally numbered following recovery in 2019 September by PanSTARRS, with further images then found from 2013. The orbit on NK 2184, from the 2011-2012 observations alone, required a Delta(T) correction of -7.2 days. It makes occasional approaches to Jupiter, most recently to 0.81 au in 2010 March. It will pass 0.63 au from the planet in 2033.  No designations seem to have been made for the 2004 or 2019 returns and the CBET does not give the number [CBET 4693, 2019 November 5].


    387P/Boattini = 2008 Y1 = 2019 R1
    Andrea Boattini discovered an 18th magnitude comet during the Catalina Sky Survey with the 0.68m Schmidt on 2008 December 22.09. Several observers confirmed the cometary nature. The comet has an elliptical orbit with period of around 10 years and perihelion in late February 2009 at 1.3 au. Brian Marsden noted on MPEC 2009-E04 [2009 March 1] that further [astrometric] observations of this comet are very desirable.

    Gennady Borisov recovered 2008 Y1 in images taken with the MARGO 0.65-m f/1.5 astrograph at Nauchnij, Crimea on September 2.01. It was placed on the PCCP as gb00239. The indicated delta-T correction to the prediction, by Brian G. Marsden on MPC 102107, is -4.38 days. [CBET 4663, MPEC 2019-R83, 2019 September 9]


    388P/Gibbs = 2007 T4 = 2019 R2
    Alex Gibbs discovered an 18th magnitude comet on Catalina Sky Survey images taken with the 0.68m Schmidt on 2007 October 12.46. The comet passed perihelion at 2.0 au in July. It has a period of around 12 years.

    Hirohisa Sato recovered 2007 T4 in images taken with an iTelescope 0.43-m f/6.8 astrograph near Mayhill, New Mexico on September 5.48. The indicated delta-T correction to the prediction on NK 1629 is -0.02 days. [CBET 4662, 2019 September 8, CBET 4664, MPEC 2019-R84, 2019 September 9]


    389P/Siding Spring = 2006 R1 = 2019 S1
    An object, of 18th magnitude, was discovered during the Siding Spring Survey with the 0.5m Uppsala Schmidt on 2006 September 1.49. The comet was near perihelion at 1.7 au and faded. It has a period of 13 years and moves in a retrograde orbit. Rob McNaught commented on the discovery
    Donna Burton is being trained as a new observer for the Siding Spring Survey, initially as a replacement for Gordon Garradd who is on 2 months sick leave following a cycling accident. Sep 01 was Donna's first time alone at the telescope. When she found 6R6F4D3 she phoned me so I went to the telescope to check on the detection and show how to schedule follow up. The first follow up was involved with a star, but the next was good. All the data was submitted. It was only with a second call later in the night with her detection of 6R6F50C that I noticed that some of the 6R6F4D3 images looked a bit soft and checking back through the other images confirmed that all images had the same appearance of diffuseness. This was confirmed for certain on images taken the following night. Thus Donna discovered the object and I noted that it was a comet, hence "Siding Spring".
    Brian Marsden commented on MPEC 2006-R41 [2006 September 10]
    It is still possible that the orbital period is somewhat longer than the best-fit value of 16 years (which would be the shortest for a comet having a retrograde orbit).
    Further observations confirmed the short period, with the latest value being 13 years.

    2006 R1 was recovered independently by Gareth Williams and R. Weryk in images from Pan-STARRS 1 taken on September 25.53. The indicated delta-T correction to the prediction, by Gareth Williams, on MPC 105244, is -6.6 days, with a period of 13.4 years.


    390P/Gibbs = 2006 W1 = 2019 U1
    Alex Gibbs discovered a 19th magnitude comet on 2006 November 16.41 during the course of the Catalina Sky Survey with the 0.68-m Schmidt.

    A comet discovered in images taken with the 0.5m Schmidt at Haleakala on 2019 October 21.25 by the ATLAS (Asteroid Terrestrial-impact Last Alert System) team was identified as a return of 2006 W1 by the MPC and Hirohisa Sato. The indicated delta-T correction to the prediction on  NK 3401 is -9.5 days.  The comet passed 1.4 au from Saturn in 2010 July.  [CBET 4685, MPEC 2019-U163, 2019 October 25] The comet is at perihelion at 1.7 au in 2020 March.


    391P/Kowalski = 2006 F1 = 2019 U2
    Richard Kowalski discovered an 18th magnitude comet on 2006 March 21.49 during the course of the Mt Lemmon survey with the 1.5-m reflector.

    The initial orbit suggested that it would reach perihelion at 1.9 au in 2007 May, however further observations however showed that it was in a periodic orbit [as first suggested by Hirohisa Sato], period 10 years, with perihelion at 4.1 au in February 2008. The comet had a very close encounter with Jupiter on 2003 January 4, when it passed 0.0096 au from the planet. It will make another close approach in 2073.

    BAA Member Kevin Hills recovered 2006 F1 (P/Kowalski) on October 22.01 in images taken with his 0.5-m f/2.9 astrograph at Tacande Observatory, La Palma. It was also recovered by PanSTARRS on October 25.35, with both sites reporting additional pre-recovery images. The indicated delta-T correction to the prediction on MPC 94677 was -0.06 days. [CBET 4686, MPEC 2019-U193, 2019 October 28]


    392P/LINEAR = 2004 WR9 = 2019 U3
    An apparently asteroidal object discovered on 2004 November 22.32 that had been on the NEOCP for several days was confirmed as a comet by Peter Birtwhistle and Carl Hergenrother. It is in a 15 year orbit with perihelion at 1.9 au in mid January 2005.

    An apparently asteroidal object discovered by LINEAR on 2004 November 22.32, and published as 2004 WR_9 on MPO 120656, has been found to show cometary appearance. P. Birtwhistle, Great Shefford, U.K., reports that CCD images taken on Dec. 7.0 UT with a 0.30-m f/6.3 reflector show the object as having a tail 20" long in p.a. 235 deg and a very concentrated coma with a diameter of 9", while on images from Dec. 3.0, there had been a suggestion of a 10" tail in p.a. 250 deg. C. Hergenrother reports that R-band images taken with the Catalina 1.54-m reflector on Dec. 8.45 show a highly condensed coma 11" in diameter and a faint tail > 25" long in p.a. 235 deg. [IAUC 8448, 2004 December 8]

    Krisztian Sarneczky recovered 2004 WR9 with the 0.6m Schmidt at the University of Szeged, Piszkesteto Station (Konkoly) on October 26.96, with confirming images on the 27th. It was 19th magnitude. The indicated delta-T correcton to the prediction, by Gareth Williams, on MPC 105245 is -0.75 days. [MPEC 2019-U245, CBET 4687, 2019 October 28].


    393P/Spacewatch-Hill = 2009 SK280 = 2019 S5
    Rik Hill discovered a 20th magnitude comet on 2009 October 15.36, during the Mt Lemmon Survey with the 1.5-m reflector. The Minor Planet Centre then identified it with earlier asteroidal images that had been taken on September 17, 25.29 and 29 by Spacewatch, with the later two linked under the designation 2009 SK280. The comet was at perihelion at 4.2 au in late May and has a period of around 10 years.

    A 21st magnitude comet was reported by Scott Sheppard on 2019 November 8 in images taken with the 4.0m reflector at the Cerro Tololo observatory on 2019 September 24.29 and 26.23. The MPC then identified it as a recovery of 2009 SK280 and found additional PanSTARRS and Mt Lemmon images from 2019 October. The indicated delta-T correction to the prediction on MPC 102108 by Gareth Williams is +0.87 days. Syuichi Nakano notes that prior to a close approach of the comet to Jupiter on 1994 May 2 at a distance of 0.13 au, the comet had a slightly closer perihelion and slightly more eccentric orbit. [CBET 4697, MPEC 2019-V147, 2019 November 12]


    394P/PanSTARRS = 2011 GN5 = 2020 F4
    PanSTARRS 1 discovered a comet in images taken with the 1.8m Ritchey-Chretien on 2020 March 24.52. It was placed on the PCCP as P10YaJ8. Very quickly, Richard Weryk of PanSTARRS found pre-discovery images from 2009, 2011 (when it was given the designation 2011 GN5), 2018, 2019 and 2020. Additional NEAT images were then found from 2002. The object was effectively stellar in 2009 and 2011. [CBET 4742, MPEC 2020-G64 2020 April 6] The comet was at perihelion at 2.7 au in 2019 November and has a period of 9 years.
    395P/Catalina-NEAT =2005 JD108 = 2020 H1
    An 18th magnitude comet found by NEAT on 2005 June 28.40 has been linked to an asteroid detected by the Catalina Sky Survey on 2005 May 12.43 and with observations by LONEOS on 2005 May 13. It reached perihelion in mid August 2005 at 4.1 au and has a period of 16.3 years.  It can make close approaches to Jupiter (0.11 au in 1971 and 0.20 au in 2078) and Uranus (0.13 au in 1949).

    The comet was recovered on 2020 April 26.08 by Erwin Schwab in images taken by Diana Abreu with the 1.0m reflector at the ESA Optical Ground Station, Tenerife. The recovery was confirmed by P Breitenstein with the Faulkes-North   [CBET 4758, MPEC 2020 H-2020, 2020 April 28]  The comet has perihelion at 4.1 au in 2021 December and a period of 16.8 years.


    396P/Leonard = 2002 F4 = 2020 F1
    Gregory J Leonard discovered a comet of 20th magnitude in images taken with the Mt Lemmon Survey 1.5m reflector on 2020 March 16.33. It was placed on the PCCP as C2CU0U2. There were pre-discovery images from PanSTARRS in 2019 January, December and 2020 January and from Mt Lemmon in 2020 February. [CBET 4736, MPEC 2020-F144, 2020 March 26]. The comet was at perihelion at 4.0 au in 2019 August and has a period of 18 years.

    With a published orbit, several researchers looked for pre-discovery observations in archival data, coming up with observations made in 2002 March.  It was given a designation of 2002 F4 for this return. The linked orbit shows that the comet made a close pass of 0.0074 au to Saturn on 1936 May 7. Prior to that time the orbit had a perihelion distance of around 9.0 au and a period of 37 years - a typical Centaur. It has since made moderately close passages to both Jupiter and Saturn. [CBET 4737, 2020 March 27, MPEC 2020-K92, 2020 May 21]

    For some reason the current MPC lists do not give it a name.


    397P/Lemmon = 2012 SB6 = 2020 M2
    An asteroidal object of 19th magnitude found during the Mt Lemmon Survey with the 1.5m reflector on 2012 September 17.42, was later seen to have cometary characteristics. Images taken shortly before discovery by the Catalina Sky Survey were also found. The comet was near perihelion at 2.4 au and has a period of around 7.7 years.

    Hirohisa Sato recovered the comet in images taken with the 0.51-m f/6.8 iTelescope astrograph at Siding Spring on June 29.82, with confirming images with the 0.43-m f/6.8 iTelescope astrograph at Mayhill the following day. The linked orbit shows that the comet passed 0.14 au from Jupiter in 1928 September, just before its 1928 perihelion; prior to that close approach, the orbit had q = 4.58 au and e = 0.20. [CBET 4807, MPEC 2020-N01, 2020 July 1]


    398P/Boattini = 2009 Q4 = 2020 P2
    Andrea Boattini discovered a 19th magnitude comet during the Catalina Sky Survey with the 0.68m Schmidt on August 26.47. Several amateur observers confirmed the cometary nature. The comet reached perihelion at 1.3 au in mid November and has a period of 5.6 years.

    Nicolas Erasmus of The ATLAS (Asteroid Terrestrial-impact Last Alert System) team discovered a 19th magnitude object in images taken with the 0.5m Schmidt at Mauna Loa on August 11.58. It was posted on the PCCP as A10oYh3 and the next day deleted and reported on the "Previous NEO Confirmation Page Objects" as P/2020 P2. There was no MPEC or CBET linked to it at this point. CBET 4829 was issued on August 16. After posting on the PCCP, Hirohisa Sato had noted that it appeared to be a recovery of 2009 Q4, some 10' from the expected position.

    The comet passed 0.55 au from Jupiter in 1984 June. It will pass 0.4 au from the Earth in 2020 December, when it could reach 14th magnitude.


    399P/PanSTARRS = 2013 O2 = 2020 O4
    Pan-STARRS discovered a 21st magnitude comet on 2013 July 16.60 [MPEC 2013-O53, 2013 July 27]  It reached perihelion at 2.1 au in 2013 December and has a period of around 7.5 years.  It makes occasional approaches to Jupiter, most recently to within 0.3 au in 1994. This reduced the perihelion distance from 2.6 au to its present value.

    Syuichi Nakano noticed that recovery observations of 2013 O2 had been published in recent MPECs listing observations of comets (2020-P19, Q175 and R04). The earliest observations (2020 July 30.36) were by Mt Lemmon, with several other observers/observatories including Werner Hasubick at Buchloe also observing the comet. Nakano then computed a linked orbit and an MPEC was issued giving a designation, followed by the CBET. [MPEC 2020-R32, CBET 4844, 2020 September 7]

    This is another out of order numbering, which should have been 404 if numbered sequentially.


    Published by Jonathan Shanklin. Jon Shanklin - jds@ast.cam.ac.uk