BAA Comet Section : Comets discovered in 2015

Updated 2017 January 1


  • 2015 A1 (PanSTARRS)
  • 2015 A2 (PanSTARRS)
  • 2015 A3 (P/PanSTARRS)
  • A/2015 AO44 [PanSTARRS-Catalina]
  • 2015 B1 (PanSTARRS)
  • 2015 B2 (PanSTARRS)
  • 2015 B3 (317P/WISE)
  • 2015 B4 (P/Lemmon-PanSTARRS)
  • A/2015 BX514 [PanSTARRS]
  • 2015 C1 (P/TOTAS-Gibbs)
  • 2015 C2 (SWAN)
  • 2015 D1 (SOHO)
  • 2015 D2 (PanSTARRS)
  • 2015 D3 (PanSTARRS)
  • 2015 D4 (Borisov)
  • 2015 D5 (P/Kowalski)
  • 2015 D6 (P/Lemmon-PanSTARRS)
  • 2015 ER61 (PanSTARRS)
  • A/2015 EV [Mt Lemmon]
  • 2015 F1 (P/PanSTARRS)
  • 2015 F2 (Polonia)
  • 2015 F3 (SWAN)
  • 2015 F4 (Jacques)
  • 2015 F5 (SWAN-Xingming)
  • 2015 G1 (319P/Catalina-McNaught)
  • 2015 G2 (MASTER)
  • 2015 GX (PanSTARRS)
  • 2015 H1 (Bressi)
  • 2015 H2 (PanSTARRS)
  • 2015 HC10 (320P/McNaught)
  • 2015 HG16 (P/PanSTARRS)
  • 2015 J1 (PanSTARRS)
  • 2015 J2 (PanSTARRS)
  • 2015 J3 (P/NEOWISE)
  • 2015 J4 (325P/Yang-Gao)
  • 2015 K1 (MASTER)
  • 2015 K2 (PanSTARRS)
  • 2015 K3 (324P/La Sagra)
  • 2015 K4 (PanSTARRS)
  • 2015 K5 (P/PanSTARRS)
  • A/2015 KJ153 []
  • 2015 LC2 (PanSTARRS)
  • 2015 M1 (PanSTARRS)
  • 2015 M2 (P/PanSTARRS)
  • 2015 M3 (PanSTARRS)
  • 2015 O1 (PanSTARRS)
  • 2015 P1 (326P/Hill)
  • 2015 P2 (327P/Van Ness)
  • 2015 P3 (SWAN)
  • 2015 P4 (P/PanSTARRS)
  • 2015 PD229 (P/Cameron-ISON)
  • 2015 Q1 (P/Scotti)
  • 2015 Q2 (P/Pimentel)
  • 2015 R1 (P/PanSTARRS)
  • 2015 R2 (P/PanSTARRS)
  • 2015 R3 (PanSTARRS)
  • A/2015 RK245 [Catalina]
  • 2015 S1 (328P/LONEOS-Tucker)
  • 2015 T1 (329P/LINEAR-Catalina)
  • 2015 T2 (PanSTARRS)
  • 2015 T3 (P/PanSTARRS)
  • 2015 T4 (PanSTARRS)
  • 2015 T5 (Sheppard-Tholen)
  • 2015 TO19 (P/Lemmon-PanSTARRS)
  • 2015 TP200 (LINEAR)
  • 2015 TQ209 (LINEAR)
  • A/2015 TB145 [PanSTARRS]
  • A/2015 TS350 [PanSTARRS]
  • 2015 U1 (330P/Catalina)
  • 2015 V1 (PanSTARRS)
  • 2015 V2 (Johnson)
  • 2015 V3 (PanSTARRS)
  • 2015 V4 (PanSTARRS)
  • 2015 V4 (PanSTARRS)
  • 2015 VL62 (Lemmon-Yeung-PanSTARRS)
  • 2015 W1 (Gibbs)
  • 2015 W2 (P/Catalina)
  • 2015 X1 (P/PanSTARRS)
  • 2015 X2 (Catalina)
  • 2015 X3 (P/PanSTARRS)
  • 2015 X4 (Elenin)
  • 2015 X5 (PanSTARRS)
  • 2015 X6 (P/PanSTARRS)
  • 2015 X7 (ATLAS)
  • 2015 X8 (NEOWISE)
  • 2015 XY1 (Lemmon)
  • A/2015 XQ384 [PanSTARRS]
  • A/2015 XR384 [PanSTARRS]
  • 2015 Y1 (LINEAR)
  • 2015 YG1 (NEOWISE)
  • A/2015 YY18 [PanSTARRS]

  • 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.

    Observations of new and periodic comets in 2015 are given in ICQ format. 

    Full details of recently discovered objects will not appear until they are available on the CBAT web pages. The actual accuracy of preliminary orbits is often (nearly always) much worse than the published accuracy implies.  In part this is because each orbital solution is treated as a mathematical construct and does not take account of observational error.  JPL does publish the errors, whereas the MPECs do not.


    2015 A1 (PanSTARRS)
    A 20th magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on January 8.62. [CBET 4043, MPEC 2015-A42, 2015 January 15] The comet is at perihelion at 2.0 au in 2015 March and has a period of around 90 years.
    2015 A2 (PanSTARRS)
    A 21st magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on January 12.25. [CBET 4044, MPEC 2015-B12, 2015 January 16] The comet is at perihelion at 5.3 au in 2015 August.
    2015 A3 (P/PanSTARRS)
    A 21st magnitude asteroidal object was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on January 8.22. Imaging with the 3.6m Canada-France-Hawaii reflector at Mauna Kea on January 18.3 showed cometary features. [CBET 4060, MPEC 2015-B134, 2015 January 25] The comet is at perihelion at 1.2 au in 2015 February and has a retrograde orbit with a period of around 20 years. Its absolute magnitude is one of the faintest on record. At a favourable return it could approach to 0.2 au of the Earth.  It is classed as a Halley type comet.
    A/2015 AO44 = 2014 WB497 [PanSTARRS-Catalina]
    An asteroid discovered by the Catalina Sky Survey on January 15 was linked to an object discovered by PanSTARRS on 2014 November 27. [MPEC 2015-V65, 2015 November 7] The asteroid, classified as a Centaur, was at perihelion at 3.6 au in 2015 July and is in a retrograde orbit with a period of around 100 years. The orbit has a Tisserand criterion with respect to Jupiter of -1.50.
    2015 B1 (PanSTARRS)
    A 20th magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on January x.xx. [CBET 4064, MPEC 2015-C12, 2015 February 4] The comet is at perihelion at 6.0 au in 2015 September and has a period of around 30 years.
    2015 B2 (PanSTARRS)
    A 20th magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on January 29.44. There were pre-discovery PanSTARRS images from January 6.5.  [CBET 4065, MPEC 2015-C71, 2015 February 13] The comet is at perihelion at 3.4 au in 2016 May.
    2015 B3 (317P/WISE)
    PanSTARRS recovered P/2010 K2 in images taken with the 1.8m Ritchey-Chretien on January 26.46, with further images on March 18.35. The comet 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.
    2015 B4 (P/Lemmon-PanSTARRS)
    A 21st magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on 2016 March 13.44. Gareth Williams linked this to apparently asteroidal objects found by the Mt Lemmon Survey on 2015 January 16.40 and by PanSTARRS on 2015 February 16.29. In both cases the object had been placed on the NEOCP, but without any follow-up observations. Further pre-discovery images were then found. The comet was designated for the first observation. [CBET 4264, MPEC 2016-F01, 2016 March 16] The comet was at perihelion at 3.8 au in 2015 February and has a period of around 25 years.
    A/2015 BX514 [PanSTARRS]
    PanSTARRS 1 discovered a 21st magnitude asteroid in images taken with the 1.8m Ritchey-Chretien on January 18.39. [MPEC 2015-C15, 2015 February 5] The asteroid, classified as a Centaur, was at perihelion at 4.6 au in 2014 October. The orbit has a Tisserand criterion with respect to Jupiter of 2.81, and approaches the planet to 0.7 au in 2015 August.
    2015 C1 (P/TOTAS-Gibbs)
    A 20th magnitude comet was discovered in images from the Teide Observatory Tenerife Asteroid Survey taken with the 1.0m reflector on February 11.98. It was also discovered by Alex Gibbs in images taken during the Mt Lemmon Survey with the 1.5m reflector on February 13.43. [CBET 4066, MPEC 2015-D07, 2015 February 17] The comet is at perihelion at 2.9 au in 2015 May and has a period of around 17 years.
    2015 C2 (SWAN)
    Rob Matson reported a comet in SWAN images taken between February 15 and 22. Michael Mattiazzo and Vladimir Bezugly reported the same object. Terry Lovejoy imaged the comet on February 25.4 estimating it at 11th magnitude. Michael Mattiazzo also imaged the comet and was able to observe it visually at magnitude 11.5. The comet was at perihelion at 0.7 au in early March. [CBET 4068, MPEC 2015-D110, 2015 February 27] It will remain at a poor solar elongation. 

    Rob Matson provides some discovery details:

    I first spotted the comet in SWAN imagery on Sunday, February 22, when composite images were available for 2/15, 2/16, 2/17, 2/18 and 2/19. It wasn’t bright enough to be reportable yet (particularly the 2/15 image), but I was pretty confident it was real so started the process of converting raw pixel coordinates to RA/Dec and grabbing SOHO satellite ephemeris data for the dates in question. I could find no other known comets predicted to be at that location, so I computed a preliminary orbit. It didn’t take long to realize that my chances of acquiring it in 20x110 binoculars from southern California were poor due to the low solar elongation combined with northern hemisphere winter.  It would take more aperture and darker skies.   

    By Tuesday I had the comet in 8 images, and it was time to find someone on the ground who could confirm it, and to report rough positions to Dan Green and Gareth Williams. I made my usual epoch assumption for SWAN composite images (12 UT), figuring that +/- 12 hours uncertainty is better than the other alternatives. In reality, SWAN composites are stitched together from much smaller images collected over a roughly 24-hour period, so different parts of the celestial sphere are imaged at different times. (I’ve never been able to find information about SWAN’s scan pattern, or if there is ancillary data that provides the epoch of each pixel.) I sent the eight positions to Dan & Gareth.     

    I explained that my +10 estimate for the magnitude was just an educated guess based on the comet’s moderately easy detectability in the last several images. I computed a preliminary parabolic orbit and generated search ephemerides for Terry Lovejoy and Rob McNaught, which I sent to them just prior to emailing Dan & Gareth. The comet appeared to be moving at about 1.6 degrees per day, so I advised Terry and Rob that the position could be off by +/- 0.8 degrees (mostly in declination) just based on the SWAN timing uncertainty alone, and more like +/- 1 degree when SWAN’s coarse angular resolution is folded in. 

    Terry got back to me almost immediately, and mentioned that he was concerned that it might be too low for him with the possibility of local obstructions, but that weather permitting he’d give it a try.   At 1:39 am Wednesday morning (Pacific Time), Terry emailed me to say he’d found it close to the predicted position, estimated the magnitude at +11 with a 2’ coma, and said it had a short stubby tail. At this time he informed me that Michael Mattiazzo had also contacted him shortly after I had, which wasn’t surprising as Michael and I have shared discovery credit on a number of prior SWAN comets.  Once the CBET was out, I saw that Vladimir Bezugly (another veteran SWAN comet finder) had also spotted the comet.   

    It will be interesting to see if the comet turns out to be periodic; when I combined ground-based astrometry with SWAN positions, I got solutions that seemed to favour a 100- to 200-year orbit, depending on how much I shifted the epoch times of the SWAN positions.


    2015 D1 (SOHO)
    Worachate Boonplod discovered a comet in SOHO/LASCO C3 images taken at 07:06, 07:18 and 07:30 on February 18.

    Karl Battams notes that the comet's image appeared tiny at first (just above the noise at about 9th magnitude) and gradually brightened as it neared the sun, but was surprised to see that it then dramatically brightened to magnitude about 1.5 as it crossed into the C2 field-of-view, when a short, faint tail appeared (February 19) and remained visible for the rest of the comet's visible passage (fading to magnitude around 6 by the time it left LASCO's field-of-view (February 21.77).

    Matthew Knight, Lowell Observatory, has analyzed the SOHO images and reports that the comet was first visible late on February 17 right at the detection limit in C3 (magnitude about 9.5-10), and peak brightness occurred around February 19.9 at an apparent V magnitude of about 1.3.  It showed much more cometary appearance during the second half of the visible apparition, and the tail seemed more distinct as it was fading.

    Pre- and post-perihelion solutions were required to fit the observations; together with the appearance of the tail near perihelion and rapid brightening, it is possible that some large physical change (perhaps splitting) occurred around that time. [CBET 4067, MPEC 2015 D73, 2015 February 24]

    The CBET gives the discovery time as February 18.004. No error-bars are given for their orbit solutions. As there is a relatively small arc, and the SOHO positions are of low accuracy, it is not clear how significantly different are the pre and post perihelion orbits. The JPL orbit based on a three day arc classes it as a Jupiter family comet with a period of around 11 years.

    The comet has been recovered from the ground, however it only shows as a dusty streak on images taken by Justin Cowart.


    2015 D2 (PanSTARRS)
    A 20th magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on February 18.39. There were pre-discovery PanSTARRS images from January 19.5.  [CBET 4069, MPEC 2015-D111, 2015 February 27] The comet was at perihelion at 5.6 au in 2013 September and has a period of around 50 years. The orbit has a Tisserand criterion with respect to Jupiter of 2.61.
    2015 D3 (PanSTARRS)
    A 20th magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on February 19.49. [CBET 4070, MPEC 2015-D112, 2015 February 27] The comet is at perihelion at 8.1 au in 2016 May.
    2015 D4 (Borisov)
    Gennady Borisov discovered a 17th magnitude comet in images taken with a 0.3m astrograph at Nauchnij, Crimea on February 23.10. [CBET 4071, MPEC 2015-E08, 2015 March 2] The comet was at perihelion at 0.9 au in 2014 October.
    2015 D5 (P/Kowalski)
    Richard Kowalski discovered a 19th magnitude comet in images taken during the Mt Lemmon Survey with the 1.5m reflector on February 27.27. [CBET 4072, MPEC 2015-E09, 2015 March 2] The comet was at perihelion at 4.6 au in 2014 April and has a period of around 30 years.
    2015 D6 (P/Lemmon-PanSTARRS)
    MPEC 2015-F31 issued on 2015 March 19 was supposed to give discovery positions of the comet, however by some quirk two MPECs with the same designation were issued, both giving details of asteroid 2015 FS. This was corrected with the asteroid going on MPEC 2015-F32.  In addition, at the same time on March 19, the CBET announcing the discovery was placed on the IAUC CBET page as being issued on March 20.  The Mt Lemmon discovery observations were made on February 27.41, with PanSTARRS finding the comet on March 16.47.  The comet has a period of around 20 years and will reach perihelion at 4.6 au in July.
    A/2015 EV [Mt Lemmon]
    The Mt Lemmon survey discovered a 19th magnitude asteroid in images taken with the 1.5m reflector on March 11.22. [MPEC 2015-E46, 2015 March 13] The asteroid, classified as an Apollo, is at perihelion at 0.08 au in 2015 April and has a period of around 3 years. The orbit has a Tisserand criterion with respect to Jupiter of 2.88. It has a MOID from Earth of 0.006au and reached 0.10au from our planet shortly after discovery. The orbit has some similarities with some SOHO comets and it will be interesting to see if it becomes visible as it passes through the SOHO C3 and C2 fields between April 10 and 26. It is at perihelion around April 20.
    2015 ER61 (PanSTARRS)
    PanSTARRS 1 discovered a 21st magnitude asteroid in images taken with the 1.8m Ritchey-Chretien on March 14.37. Peter Birtwhistle contributed confirming astrometry. [MPEC 2015-F124, 2015 March 27] The asteroid, originally classified as an Amor type NEO, but in a near parabolic orbit, is at perihelion at 1.1 au in 2017 May. The orbit has a Tisserand criterion with respect to Jupiter of 1.27, a Jupiter MOID of 0.029 au and an earth MOID of 0.10 au.

    Observations in 2015 December and 2016 January showed that the object had cometary features and a coma was then noted in images from 2015 June.  It was therefore re-designated as a comet on MPEC 2016-C01 [2016 February 1]. Unfortunately the comet doesn't actually approach us particularly closely.

    Juan Gonzalez recovered the comet after solar conjunction on December 6.25 at 10.4.  The comet is brightening relatively rapidly, though the rate is slowing and should soon come within binocular range.  The actual magnitude around the time of perihelion is still poorly constrained but it might reach 4th magnitude.  The comet will unfortunately be an early morning object through the brighter phases of the apparition and does not get into the mid-evening sky until the autumn of 2017.


    2015 F1 (P/PanSTARRS)
    A 19th magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on March 21.58. [CBET 4082, MPEC 2015-F119, 2015 March 26] The comet was at perihelion at 2.5 au in 2015 March and has a period of around 7 years.
    2015 F2 (Polonia)
    A 17th magnitude object was discovered at the Polonia Observatory, San Pedro de Atacama by Marcin Gedek, Michal Zolnowski, Michal Kusiak and Rafal Reszelewski with the 0.1-m f/5 astrograph on March 23.29. [CBET 4083, MPEC 2015-F120, 2015 March 26] The comet was at perihelion at 1.2 au in late April and has a period of around 250 years. The Polonia observatory is an amateur Polish facility located Chile.
    2015 F3 (SWAN)
    Rob Matson reported a comet in SWAN images taken in March. It was soon confirmed by ground based observers, including Peter Birtwhistle. [CBET 4084, MPEC 2015-F122, 2015 March 27] The comet was at perihelion at 0.8 au in early March. The orbital parameters are similar to those of 1988 A1 (Liller) and 1996 Q1 (Tabur). Internet observations suggest it is around 11th magnitude visually. It will fade, but its solar elongation increases and it will become circumpolar from the UK.

    1996 Q1 was discovered by an Australian amateur Vello Tabur on 1996 August 19.70. After reaching naked eye brightness in mid October, the comet suddenly faded dramatically. The orbit is very similar to that of 1988 A1 (Liller), which reached perihelion on 1988 Mar 31. It seems likely that these two comets separated at their last perihelion passage, about 2900 years ago.

    8 visual observations received so far suggest a preliminary light curve of m = 9.8 + 5 log d + 6.9 log r


    2015 F4 (Jacques)
    Cristovao Jacques discovered a 16th magnitude comet on images taken with the SONEAR Observatory 0.28m astrograph on March 27.21 [CBET 40xx, MPEC 2015-F159, 2015 March 31]. The comet has perihelion at 1.6 au in 2015 August, when it is near opposition and may be 13th magnitude.  It was already 12th magnitude when observed by Juan Jose Gonzalez on June 18.08.

    43 visual and electronic observations received so far suggest a preliminary light curve of m = 5.6 + 5 log d + 25.9 log r


    2015 F5 (SWAN-Xingming)
    The PCCP object XMAAGS has been designated as 2015 F5. It was reported by several people, including Szymon Liwo, Worachate Boonplod, Michael Mattiazzo and Rob Matson in SWAN images taken between March 29 and April 1. It was independently found by Guoyou Sun in images taken in twilight on April 4.9 by Xing Gao with a 0.11-m f/5 refractor in the course of the Xingming sky survey. It was at perihelion at 0.3 au at the end of March and has a period of around 60 years.  The comet will fade rapidly, but moves north, so becoming better placed for observation from the UK.

    2 visual observations received so far suggest a preliminary light curve of m = 12.5 + 5 log d + [10] log r


    2015 G1 (319P/Catalina-McNaught)
    An object found in infra-red images from the NEOWISE satellite on 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.
    2015 G2 (MASTER)
    The PCCP object M503ujx has been designated as 2015 G2. The comet was reported by Denis Denisenko in R-band images taken by P. Balanutsa et al. with the MASTER (Mobile Astronomical System of the Telescope-Robots) 0.4-m f/2.5 reflector at the South African Astronomical Observatory on April  7.13.  Rob Kaufman from Australia noted the comet in pre-discovery images taken on March 30.80.  It was at perihelion at 0.8 au in May.  It brightened to around 6th magnitude at perihelion and is now fading.

    The text of the original CBET 4092 was replaced by CBET 4104 issued on May 23.

    81 visual observations received so far suggest a preliminary light curve of m = 8.2 + 5 log d + 7.1 log r


    2015 GX (PanSTARRS)
    A 20th magnitude asteroid was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on April 8.58. It was subsequently found to show cometary activity by astrometrists including Roberto Haver, L Buzzi and H Sato. [CBET 4109, MPEC 2015-L07, 2015 June 4] The comet is at perihelion at 2.0 au in 2015 August and has a period of around 65 years.  
    2015 H1 (Bressi)
    Tim Bressi discovered an 18th magnitude comet in images taken with the 0.9-m Spacewatch telescope at Kitt Peak on April 20.46. [CBET 4095, MPEC 2015-H100, 2015 April 23]. The comet was at perihelion at 1.9 au in late March and has a retrograde orbit with a period of around 200 years.
    2015 H2 (PanSTARRS)
    A 20th magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on April 24.40. [CBET 4096, MPEC 2015-J04, 2015 May 2] The comet is at perihelion at 5.0 au in 2016 September.
    2015 HC10 (320P/McNaught)
    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 HC_10. Gareth Williams, F. Manca, and P. Sicoli then each identified 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.
    2015 HG16 (P/PanSTARRS)
    A 22nd magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on 2016 April 4.48. R Weryk from the PanSTARRS team then found the object in images taken the day before, and then from February 11. Gareth Williams linked these observations to an asteroid discovered by PanSTARRS on 2015 April 20.33. Weryk independently found further images from 2015 March 24 and April 9. [CBET 4270, MPEC 2016-G114, 2016 April 7] The comet was at perihelion at 3.1 au in 2014 June and has a period of 10.5 years.
    2015 J1 (PanSTARRS)
    A 20th magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on May 14.34. [CBET 4099, MPEC 2015-K17, 2015 May 19] The comet was at perihelion at 6.0 au in 2014 July.
    2015 J2 (PanSTARRS)
    A 20th magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on May 15.49. [CBET 4100, MPEC 2015-K18, 2015 May 19] The comet is at perihelion at 4.3 au in 2015 September.
    2015 J3 (P/NEOWISE)
    A 19th magnitude object found by the NEOWISE satellite on May 15.06 was found to show cometary features by ground based astrometrists after the object was posted on the PCCP. [CBET 4102, MPEC 2015-K55, 2015 May 23] The comet was at perihelion at 1.5 au in 2015 March and has a period of around 6 years.
    2015 J4 (325P/Yang-Gao)
    Hidetaka Sato recovered 2009 L2 (P/Yang-Gao) with the 0.51m iTelescope at Siding Spring on May 11.38 with confirming images taken on June 9 and 10. [MPEC 2015-L28, 2015 June 10].
    2015 K1 (MASTER)
    CBET 4103, issued on May 23 and giving the discovery of 2015 K2 had an Editorial note: The cometary designation 2015 K1 has been given to another comet that was planned for announcement first, but political issues are preventing announcement prior to this comet.

    The discovery was announced later the same day in CBET 4105. The comet was one of around 50 potential objects found in images taken by with the MASTER (Mobile Astronomical System of the Telescope-Robots) 0.4-m f/2.5 reflector at the South African Astronomical Observatory on May 17.14. Denis Denisenko noted that it showed a diffuse appearance and this was confirmed by other astrometrists. [CBET 4105, MPEC 2015-K70, 2015 May 23]. The comet was at perihelion at 2.6 au in 2014 October.


    2015 K2 (PanSTARRS)
    A 22nd magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on May 18.33. [CBET 4103, MPEC 2015-K56, 2015 May 23] The comet was at perihelion at 1.5 au in 2015 June.
    2015 K3 (324P/La Sagra)
    Comet 2010 R2 (P/La Sagra) was recovered by S. S. Sheppard with the Magellan-Baade telescope in images taken in 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 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]
    2015 K4 (PanSTARRS)
    A 19th magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on May 24.47. [CBET 4108, MPEC 2015-K114, 2015 May 27] The comet was at perihelion at 2.0 au in 2015 May.
    2015 K5 (P/PanSTARRS)
    A 20th magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on May 29.43, with prediscovery images from May 11.52. [CBET 41xx, MPEC 2015-L26, 2015 June 10] The comet was near perihelion at 3.0 au and has a period of around 17 years.
    A/2015 KJ153 []
    [MPEC 2015-M01, 2015 June 16] The asteroid, classified as a Centaur, will be at perihelion at 2.7 au in 2015 August. The orbit has a Tisserand criterion with respect to Jupiter of 2.53, and approaches both Jupiter and Saturn to within 1.0 au.
    2015 LC2 (PanSTARRS)
    A 19th magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on June 22.30. Soon after posting on the PCCP Gareth Williams linked it to an asteroid discovered by PanSTARRS on images from June 7 and 8. [CBET 4113, MPEC 2015-M54, 2015 June 24] The comet was at perihelion at 5.9 au in 2015 May.
    2015 M1 (PanSTARRS)
    A 20th magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on June 20.45. [CBET 4112, MPEC 2015-M45, 2015 June 22] The comet was at perihelion at 2.1 au in 2015 May.
    2015 M2 (P/PanSTARRS)
    A 20th magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on June 28.57. [CBET 4117, MPEC 2015-N46, 2015 July 15] The comet will be at perihelion at 5.9 au in 2015 September and has a period of around 20 years.
    2015 M3 (PanSTARRS)
    A 20th magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on June 29.43. [CBET 4118, MPEC 2015-N47, 2015 July 15] The comet is at perihelion at 3.6 au in 2015 August.
    2015 O1 (PanSTARRS)
    A 20th magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on July 19.47. [CBET 4119, MPEC 2015-O34, 2015 July 21] The comet will reach perihelion at 3.7 au in 2018 February.  This was PanSTARRS 100th comet.
    2015 P1 (326P/Hill)
    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].
    2015 P2 (327P/Van Ness)
    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].
    2015 P3 (SWAN)
    Michael Mattiazzo identified a possible comet in SWAN images from August 3 and 4, and confirmed it with an image he took on August 9.38 from Castlemaine, Australia. This was also confirmed by other astrometrists and observed visually at around 12th magnitude. The comet was near perihelion at 0.7 au in late July. [CBET 4136, MPEC 2015-P25, 2015 August 11]. Hirohisa Sato suggests that the comet is in a long period orbit with aphelion at around 500 au.  The elongation of the comet improved, although it faded quite quickly.  Visual observations put the comet at around 10.5 in mid August.  

    5 visual observations received so far give a preliminary light curve of m = 11.8 + 5 log d + [10] log r


    2015 P4 (P/PanSTARRS)
    A 21st magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on August 14.50, with prediscovery images from July 24.54. [CBET 4137, MPEC 2015-Q24, 2015 August 19] The comet is at perihelion at 2.5 au in 2016 January and has a period of around 15 years.
    2015 PD229 (Cameron-ISON)
    Gareth Williams notes in MPEC 2015-Q17 [2015 August 18]
    This object was reported as a comet found on May 27.36 (without any details on appearance) by the Cerro Tololo DECam team on August 14. It was reported as a NEOCP candidate found on August 15.71 on August 16 by the ISON-Siding Spring team. Details on the cometary appearance in May were submitted on August 18, following prompting by Gareth Williams. The linkage of the two sets of observations was made after the object was removed from the NEOCP and designated. None of the August reports have mentioned detecting cometary features, hence the announcement under a minor-planet designation. There is a roughly two-magnitude discrepancy in the absolute magnitudes determined from the May observations alone and from the August observations alone. Confirmation of any possible cometary activity is therefore very desirable.
    The object was classed as a Centaur and has a period of 19 years with perihelion at 4.8 au in 2015 August.

    It was re-designated as a comet [CBET 4251, MPEC 2016-C02, 2016 February 1], although no further evidence of cometary activity had been detected.  It has a Jupiter MOID of 0.11 au.  The comet name was changed from ISON-Cameron to Cameron-ISON following a vote by the Working Group on Small-Body Nomenclature in 2016 April.


    2015 Q1 (P/Scotti)
    Jim Scotti discovered a 19th magnitude comet in images taken with the 0.9-m Spacewatch telescope at Kitt Peak on August 18.46. [CBET 4138, MPEC 2015-Q25, 2015 August 19]. The comet was at perihelion at 1.8 au in September and has a period of around 6 years [MPEC 2015-S97, 2015 September 28].  By contrast JPL gave a nearly parabolic orbit until late September, but did publish error bars.
    2015 Q2 (P/Pimentel)
    Cristovao Jacques has reported the discovery of a comet on CCD exposures obtained by Eduardo Pimentel on August 24.20 with a 0.45-m f/2.9 reflector of the SONEAR Observatory at Oliveira, Brazil. The object appeared slightly cometary on August 24, but the reality of the object's features (and indeed the object itself) was questioned, and so follow-up observations to confirm the object were obtained by Jacques, Pimentel, and J. Barros with the same telescope on August 27.3 and 31.3; on the 27th, a diffuse object with a 15" coma was identified by Jacques that he assumed was not the same object observed on the 24th, and he reported it to the Central Bureau and the Minor Planet Center as an apparent new comet, with observations given for August 27 and 31.  Later, Jacques concluded that the object observed on the first night was identical to that observed on the second and third nights. [CBET 4140, MPEC 2015-R02, 2015 September 1] The comet was near perihelion at 1.8 au and has a retrograde orbit with a period of around 20 years.
    2015 R1 (P/PanSTARRS)
    A 19th magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on September 8.57. [CBET 4141, MPEC 2015-R39, 2015 September 11] The comet was at perihelion at 2.2 au in 2015 June and has a period of around 14 years.
    2015 R2 (P/PanSTARRS)
    A 22nd magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on September 9.41. [CBET 4142, MPEC 2015-S01, 2015 September 16] The comet was at perihelion at 2.5 au in 2015 June and has a period of around 9 years.
    2015 R3 (PanSTARRS)
    A 22nd magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on September 12.58. [CBET 4143, MPEC 2015-S02, 2015 September 16] The comet was at perihelion at 4.9 au in 2014 February.
    A/2015 RK245 [Catalina]
    An object with an unusual orbit, which was on the PCCP for nearly a month, did not show any cometary features and so was eventually given an asteroidal designation. Discovered by the Catalina Sky Survey on September 13.44, the 19th magnitude asteroid has a just retrograde orbit with perihelion at 2.8 au and a period of around 900 years. The object, currently classed as a Trans-Neptunian Object, reaches perihelion in 2016 February.  It has aphelion at nearly 200 au.

    Gareth Williams notes on MPEC 2015-T32, 2015 October 9]:

    Richard Wainscoat reports that 2015 RK245 looked entirely asteroidal on images obtained with the 3.58-m CFHT on Mauna Kea on October 9. The seeing was not particularly good: for the first two images, it was 1".1; for the third, it was 0".85. The telescope was tracked on the motion of the object. In the direction perpendicular to the motion, the PSF of 2015 RK245 looked identical to that of adjacent stars. Wainscoat concludes "that there is no morphological evidence from the images of this being cometary."

    2015 S1 (328P/LONEOS-Tucker)
    Alex Gibbs discovered an 18th magnitude comet during the Catalina Sky Survey with the 0.68m Schmidt on 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]
    2015 T1 (329P/LINEAR-Catalina)
    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 referenced ICQ Handbook does not appear to have any functional web links to it.
    2015 T2 (PanSTARRS)
    A 22nd magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on October 9.47. [CBET 4149, MPEC 2015-T77, 2015 October 13] The comet is at perihelion at 6.9 au in 2017 May.
    2015 T3 (P/PanSTARRS)
    A 21st magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on October 13.41. [CBET 4152, MPEC 2015-U02, 2015 October 16] The comet is at perihelion at 2.1 au in 2015 December and has a period of around 9 years.
    2015 T4 (PanSTARRS)
    A 19th magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on October 14.53. [CBET 4153, MPEC 2015-U03, 2015 October 16] The comet will reach perihelion at 2.3 au in 2016 June. Hirohisa Sato notes that it is in a long period orbit of around 400 years.  It may reach 13th magnitude around the time of perihelion, when it is at high southern declination.
    2015 T5 (Sheppard-Tholen)
    Scott Sheppard and David Tholen discovered a 22nd magnitude comet in images taken with the 2.24m and 8.2m University of Hawaii reflectors on Mauna Kea on October 13.26. It was eventually confirmed in early November. [CBET 4177, MPEC 2015-V166, 2015 November 15] The comet will reach perihelion at 9.3 au in 2016 January and has a period of around 150 years.
    2015 TO19 (P/Lemmon-PanSTARRS)
    A 20th magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on October 13.35. Gareth Williams then found astrometry from Catalina on October 8 and PanSTARRS on October 12 and then to Mount Lemmon Survey astrometry on October 3 and 4 which had been given the minor planet designation. He was then able to find pre- discovery PanSTARRS images from September 12. [CBET 4151, MPEC 2015-T117, 2015 October 15] The comet is at perihelion at 2.9 au in 2016 March and has a period of around 10 years.
    2015 TP200 (LINEAR)
    LINEAR (The 3.5m reflector Space Surveillance Telescope at the Atom site) discovered a 20th magnitude asteroid on 2015 October 10.28. The object was posted on the PCCP, but not confirmed as a comet. Whilst taking follow-up images on 2016 August 3.47 with the iTelescope 0.51-m f/6.8 astrograph, Hidetaka Sato noted that it was some three magnitudes brighter than expected and showed a coma. Peter Birtwhistle made confirming images using his 0.40-m f/6 Schmidt-Cassegrain. [CBET 4303, MPEC 2016-P132, 2016 August 15]  The comet has perihelion at 3.4 au in 2016 October and has a period of around 20 years.
    2015 TQ209 (LINEAR)
    A 19th magnitude asteroid discovered by LINEAR (The 3.5m reflector Space Surveillance Telescope at the Atom site) on October 10.33 was shown to have cometary features when observed by other astrometrists [CBET 4156, MPEC 2015-U52, 2015 October 24]  The comet has perihelion at 1.4 au in 2016 August.  The comet is on the opposite side of the Sun when at perihelion, so will not put on a good show.  
    A/2015 TB145 [PanSTARRS]
    PanSTARRS 1 discovered a 20th magnitude asteroid in images taken with the 1.8m Ritchey-Chretien on October 10.53. [MPEC 2015-T86, 2015 October 13] Peter Jenniskens and Jeremy Vaubaillon suggest that the object is a possible dormant comet. It is not expected to produce any meteors in 2015, and does not appear to have produced any since 2007. [CBET 4154, 2015 October 24] The asteroid, classified as an Apollo type NEO and PHA, is at perihelion at 0.3 au in 2015 December. The orbit has a Tisserand criterion with respect to Jupiter of 3.00, and it has an earth MOID of 0.002 au.
    A/2015 TS350 [PanSTARRS]
    PanSTARRS 1 discovered a 22nd magnitude asteroid in images taken with the 1.8m Ritchey-Chretien on October 15.46. [MPEC 2015-U67, 2015 October 31] Classed as a TNO it has a period of around 2000 years with perihelion at 5.1 au in 2014 January.
    2015 U1 (330P/Catalina)
    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]
    2015 V1 (PanSTARRS)
    A 20th magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on November 2.60. [CBET 4160, MPEC 2015-V43, 2015 November 5] The MPC preliminary elements suggested that the comet was at perihelion at 0.3 au in 2014 October. This seemed somewhat unlikely as the comet should have been visible as a moderately bright northern hemisphere object after perihelion. JPL gave a 1-sigma uncertainty in the time of perihelion of 110 days, so the elements were likely to change substantially. Needless to say they did. MPEC 2015-V61 issued the next day gave perihelion at 4.4 au in 2017 December. The perihelion distance is now given as 4.3 au.
    2015 V2 (Johnson)
    Jess A Johnson discovered a 17th magnitude comet in Catalina Sky Survey images with the 0.68m Schmidt on November 3.44. [CBET 4161, MPEC 2015-V44, 2015 November 5] The MPC preliminary elements suggested that the comet would reach perihelion at 0.9 au in 2017 February. JPL gave a 1-sigma uncertainty in the time of perihelion of 206 days and in perihelion distance of 0.6 au, so the elements were likely to change substantially.  Again a new MPEC was issued the next day (V62) and this gave perihelion at 1.6 au in 2017 June (which is now well determined).  The JPL elements were similar with the 1-sigma uncertainty now 5 days and an earth MOID of 0.7 au.  The latest JPL figures give an earth MOID of 0.6 au and classify the comet as a hyperbolic one.  JJ Gonzalez picked up the comet at 12th magnitude in early September 2016, much earlier than expected though consistent with extrapolation of electronic observations by Kevin Hills.  Analysis of the observations to 2016 December suggests that the comet could just reach naked eye visibility, however the rate of brightening has slowed down as it approaches perihelion.  The comet will be well placed for viewing from the UK prior to perihelion, reaching around 6th magnitude.   
    2015 V3 (PanSTARRS)
    A 22nd magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on November 2.27. [CBET 4162, MPEC 2015-V60, 2015 November 6] The MPC preliminary elements suggest that the comet was near perihelion at 4.2 au.
    2015 V4 (PanSTARRS)
    A 20th magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on November 3.62. [CBET 4174, MPEC 2015-V167, 2015 November 15] The MPC preliminary elements suggest that the comet will reach perihelion at 5.6 au and has a period of around 100 years.
    2015 VL62 (Lemmon-Yeung-PanSTARRS )
    A 20th magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on 2016 January 23.30. After posting on the PCCP it was linked first to asteroid 2015 YY6 discovered in December by Bill Yeung, then to asteroid 2015 VL62 discovered in early November 2015 from Mount Lemmon. [CBET 4247, MPEC 2016-B85, 2016 January 29] The comet is in a retrograde hyperbolic orbit and has perihelion at 2.7 au in 2017 August. It will approach Jupiter to 0.9 au in 2018 November on its way out of the solar system. It could reach around 13th magnitude around the time of perihelion.
    A/2015 VH105 [PanSTARRS]
    PanSTARRS 1 discovered a 21st magnitude asteroid in images taken with the 1.8m Ritchey-Chretien on November 1.21. [MPEC 2015-V139, 2015 November 13] The asteroid, classified as a Centaur, will be at perihelion at 1.5 au in 2016 January. The orbit has a Tisserand criterion with respect to Jupiter of 2.08.
    2015 W1 (Gibbs)
    Alex Gibbs discovered a 19th magnitude comet in Catalina Sky Survey images with the 0.68m Schmidt on November 18.49. [CBET 4195, MPEC 2015-W43, 2015 November 21] The MPC elements suggest that the comet will reach perihelion at 2.2 au in 2016 May.
    2015 W2 (P/Catalina)
    A 19th magnitude object found in Catalina Sky Survey images with the 0.68m Schmidt on November 21.22 was found to show cometary characteristics by other astrometrists. [CBET 4205, MPEC 2015-W73, 2015 November 29/30] The MPC elements suggest that the comet was at perihelion at 2.7 au in 2015 September and has a period of around 20 years.
    2015 WZ (PanSTARRS)
    PanSTARRS 1 discovered a 21st magnitude asteroid in images taken with the 1.8m Ritchey-Chretien on November 17.40. [MPEC 2015-W30, 2015 November 19] The object, originally classified as a Trans-Neptunian Object, was at perihelion at 1.4 au in 2016 April and has a retrograde orbit. The orbit has a Tisserand criterion with respect to Jupiter of -1.01. I suggested at the time that it would be interesting to see if cometary activity commenced as it approached closer to the Sun.  It did, and it was reclassified as a comet in MPEC 2016-H29 [2016 April 19].
    2015 X1 (P/PanSTARRS)
    A 20th magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on December 1.30. There were pre-discovery PanSTARRS images from August and September, and Catalina images from October. [CBET 4212, MPEC 2015-X58, 2015 December 5] The comet was at perihelion at 2.1 au in 2015 October and has a period of around 7 years.
    2015 X2 (Catalina)
    A 20th magnitude object found in Catalina Sky Survey images with the 0.68m Schmidt on December 21.47 was found to show cometary characteristics by other astrometrists. [CBET 4213, MPEC 2015-X59, 2015 December 5] The comet was near perihelion at 1.9 au and has a period of around 60 years.
    2015 X3 (P/PanSTARRS)
    A 21st magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on December 1.41. There were pre-discovery PanSTARRS images from November. [CBET 4215, MPEC 2015-X104, 2015 December 8] The comet was at perihelion at 2.8 au in 2015 August and has a period of around 11 years.
    2015 X4 (Elenin)
    Leonid Elenin discovered an 18th magnitude comet with the ISON-NM 0.4m reflector at Mayhill on December 3.49. [CBET 4216, MPEC 2015-X105, 2015 December 8] The comet was at perihelion at 3.4 au in 2015 November and has a period of around 80 years.
    2015 X5 (PanSTARRS)
    A 21st magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on December 6.55. [CBET 4220, MPEC 2015-X179, 2015 December 15] The comet is at perihelion at 6.8 au in 2017 December.
    2015 X6 (P/PanSTARRS)
    A 21st magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on December 7.27. [CBET 4221, MPEC 2015-X180, 2015 December 15] The comet is at perihelion at 2.3 au in 2016 February and has a period of around 4 years. It has a low eccentricity orbit with aphelion at 3.0 au and although JPL classify it as an Encke-type comet it may be a main belt comet.
    2015 X7 (ATLAS)
    A 17th magnitude comet was discovered by the ATLAS project 0.5m Schmidt at Haleakala on December 12.47. [CBET 4223, MPEC 2015-Y18, 2015 December 17] The comet will reach perihelion at 3.7 au in 2016 July.
    2015 X8 (NEOWISE)
    A 16th magnitude extended object was found by the NEOWISE satellite on December 14.64. This was confirmed by ground based astrometrists after the object was posted on the PCCP. [CBET 4224, MPEC 2015-Y20, 2015 December 18] The comet was at perihelion at 1.2 au in 2015 October and has a period of around 80 years.  Juan Jose Gonzalez reports the comet as being 11th magnitude visually on December 21.
    2015 XY1 (Lemmon)
    The Mt Lemmon survey discovered a 20th magnitude asteroid in images taken with the 1.5m reflector on December 4.52. Subsequent observations by other astrometrists showed that the object had cometary features. [CBET 4222, MPEC 2015-Y06, 2015 December 16] The comet has perihelion at around 7.9 au in 2018 April. 
    A/2015 XQ384 [PanSTARRS]
    PanSTARRS 1 discovered a 22nd magnitude asteroid in images taken with the 1.8m Ritchey-Chretien on December 7.47. [MPEC 2016-A51, 2016 January 6] The asteroid, classified as a Centaur, was at perihelion at 4.5 au in 2015 January and has a period around 45 years. The orbit has a Tisserand criterion with respect to Jupiter of 2.63.
    A/2015 XR384 [PanSTARRS]
    PanSTARRS 1 discovered a 22nd magnitude asteroid in images taken with the 1.8m Ritchey-Chretien on December 9.36. [MPEC 2016-A52, 2016 January 6] The asteroid, classified as a TranNeptunian Object, was at perihelion at 3.6 au in 2015 July and has a period of around 220 years. The retrograde orbit has a Tisserand criterion with respect to Jupiter of -1.97.
    2015 Y1 (LINEAR)
    An 18th magnitude object discovered by LINEAR (The 3.5m reflector Space Surveillance Telescope at the Atom site) on December 16.43 was shown to have cometary features by astrometrist after posting on PCCP. [CBET 4227, MPEC 2015-Y58, 2015 December 20]  The comet has perihelion at 2.5 au in 2016 May and is in a long period orbit. 
    2015 Y2 (332P/Ikeya-Murakami)
    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.  For further details see the periodic comets page.
    2015 YG1 (NEOWISE)
    A 19th magnitude nebulous object was found by the NEOWISE satellite on December 14.64, however it had already been given a minor planet designation before its nature was reported to the MPC. The cometary nature was confirmed by ground based astrometrists. [CBET 4228, MPEC 2015-Y59, 2015 December 20] The comet was at perihelion at 2.1 au in 2015 September and has a period of around 70 years.
    A/2015 YY18 [PanSTARRS]
    PanSTARRS 1 discovered a 20th magnitude asteroid in images taken with the 1.8m Ritchey-Chretien on December 29.52. [MPEC 2016-A53, 2016 January 6] The asteroid, classified as a Centaur, was at perihelion at 3.3 au in 2015 November and has a period of around 90 years. The retrograde orbit has a Tisserand criterion with respect to Jupiter of -0.75.
    Ephemerides of current comets are available on the CBAT ephemeris page and positions of newly discovered potential comets are on the Possible Comet Confirmation Page.
    More information on LINEAR. A list of comets discovered by selected search programs.
    Published by Jonathan Shanklin. Jon Shanklin - jds@ast.cam.ac.uk