BAA Comet Section : Comets discovered in 2017

Updated 2017 February 19


  • 2017 A1 (PanSTARRS)
  • 2017 A2 (P/PanSTARRS)
  • 2017 A3 (Elenin)
  • 2017 AX13 [A/PanSTARRS]
  • 2017 B1 (Lemmon)
  • 2017 B2 (P/McNaught)
  • 2017 B3 (LINEAR)
  • 2017 B4 (P/PanSTARRS)
  • 2017 C1 (NEOWISE)
  • 2017 C2 (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 2017 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.


    2017 A1 (PanSTARRS)
    A 19th magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on January 2.33. [CBET 4340, MPEC 2017-A31, 2017 January 6] The comet is at perihelion at 2.3 au in 2017 May.
    2017 A2 (P/PanSTARRS)
    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.
    2017 A3 (Elenin)
    Leonid Elenin discovered an 18th magnitude comet with the ISON-SSO 0.4m reflector at Siding Spring on January 5.46. [CBET 4344, MPEC 2017-A75, 2017 January 11] The comet was at perihelion at 3.9 au in 2017 January.
    A/2017 AX13 [PanSTARRS]
    PanSTARRS discovered a 22nd magnitude asteroid in images taken with the 1.8m Ritchey-Chretien on January 2.58. [MPEC 2017-A67, 2017 January 9] The asteroid, classified as a Trans-Neptunian Object, was at perihelion at 3.2 au in 2016 January and has a period of around 200 years and is in a retrograde orbit with an inclination of 137.
    2017 B1 (Lemmon)
    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.
    2017 B2 (P/McNaught)
    Jim Scotti recovered 2010 J5 (P/McNaught) with the Spacewatch 1.8m reflector on January 26.52. It returns to perihelion in 2018 January. [CBET 4352, MPEC 2017-B123, 2017 January 29/30]
    2017 B3 (LINEAR)
    A 19th magnitude object discovered by LINEAR (The 3.5m reflector Space Surveillance Telescope at the Atom Peak site) on January 26.43 was shown to have cometary features by astrometrists after posting on the PCCP. [CBET 4354, MPEC 2017-C43, 2017 February 4]  The comet has perihelion at 3.8 au in 2019 January.
    2017 B4 (P/PanSTARRS)
    A 21st magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on January 28.39. [CBET 4355, MPEC 2017-C46, 2017 February 4] The comet was near perihelion at 2.7 au and has a period of around 9 years.
    2017 C1 (NEOWISE)
    A 20th magnitude comet was discovered from the NEOWISE satellite on February 6.09. [CBET 4358, MPEC 2017-C82, 2017 February 12] The comet was at perihelion at 1.5 au in 2017 January.
    2017 C2 (PanSTARRS)
    A 20th magnitude comet was discovered in PanSTARRS 1 images taken with the 1.8m Ritchey-Chretien on February 4.26. [CBET 4362xx, MPEC 2017-D22, 2017 February 19] The comet was at perihelion at 2.4 au in 2017 January and has a period of about 1400 years.
    Ephemerides of current comets are available on the CBAT ephemeris page and positions of newly discovered 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