BAA Comet Section : Comets discovered in 2020

Updated 2020 April 9


  • 2014 OG392 (PanSTARRS)
  • A/2020 A1 (A/NEOWISE)
  • 2020 A2 (Iwamoto)
  • 2020 A3 (ATLAS)
  • A/2020 B1 (A/PanSTARRS)
  • 2020 B2 (Lemmon)
  • 2020 B3 (Rankin)
  • 2020 BS7 [A/Lemmon]
  • 2020 BZ12 [A/PanSTARRS]
  • 2020 BU13 [A/PanSTARRS]
  • 2020 EP [A/Lemmon]
  • 2020 F1 (P/Leonard)
  • 2020 F2 (ATLAS)
  • 2020 F3 (NEOWISE)
  • 2020 F4 (P/PanSTARRS)
  • 2020 F5 (MASTER)
  • 2020 F6 (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 comets in 2020 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.


    2014 OG392 (PanSTARRS)
    PanSTARRS 1 discovered a 21st magnitude asteroid in images taken with the 1.8m Ritchey-Chretien on 2014 July 28.50. There were additional pre-discovery observations back to 2011 July. The object, originally classified as a Centaur, is at perihelion at 10.0 au in 2021 November and has a period of around 40 years. CBET 4731 [2020 March 16] reports that a coma was noted in six images taken with large telescopes between 2017 July and 2019 December. It seems a long time for cometary activity to go unreported.
    A/2020 A1 (A/NEOWISE)
    An 20th magnitude object was discovered from the NEOWISE satellite on January 1.76. It was posted on the PCCP as N00g0p4. No cometary activity has been detected. [MPEC 2020-A119, 2020 January 12] The object was at perihelion at 1.7 au in 2019 December.  JPL classify it as a Centaur.
    2020 A2 (Iwamoto)
    Masayuki Iwamoto, Awa, Tokushima-ken, Japan, discovered a 13th magnitude comet on two CCD frames taken on January 8.86 with a 10-cm Pentax 400-mm-f.l. f/4.0 lens and a Canon EOS 6D camera. It was posted on the PCCP as IF033. Following posting, Gennady Borisov confirmed the 15th magnitude comet in frames taken on January 13.15. [CBET 4714, 4715, MPEC 2020-132, 2020 January 13/15] The comet was discovered at perihelion at 1.0 au.   Despite describing the orbit as very preliminary and with only five observations over a five day arc, Dan Green gives four decimal places for the angular elements on the CBET. A similar orbit, based on six observations is provided by Hirohisa Sato.  The orbit suggests that whilst it may brighten a little, it will not become brighter than 13th magnitude. Its elongation will increase, but it is a morning object. Some visual observations suggest that it may be as bright as 9th magnitude.
    2020 A3 (ATLAS)
    A 19th magnitude comet was discovered in images taken with the 0.5m Schmidt at Mauna Loa on January 7.60. by the ATLAS (Asteroid Terrestrial-impact Last Alert System) team. It had been posted on the PCCP as A10jo2S. [CBET 4716, MPEC 2020-B60, 2020 Janaury 21]. The comet was at perihelion at 5.8 au in 2019 June.
    A/2020 B1 [PanSTARRS]
    PanSTARRS 1 discovered an asteroid in images taken with the 1.8m Ritchey-Chretien on January 19.37. The object, classified by JPL as a Trans-Neptunian Object, was at perihelion at 1.7 au in 2019 December and has a long period orbit with aphelion at 100 au. It was placed on the PCCP as P10W9bB. No cometary activity has been detected.
    2020 B2 (Lemmon)
    The Mt Lemmon Survey discovered a comet of 21st magnitude in images taken with the 1.5m reflector on January 19.45. It was placed on the PCCP as C1T0QN2. Richard Miles was amongst those making confirming observations. [MPEC 2020-C110, 2020 February 6]. The comet was near perihelion at 2.8 au. It is in a long period orbit of around 500 years.
    2020 B3 (Rankin)
    David Rankin discovered a comet of 19th magnitude in images taken with the 1.5m reflector on January 29.44 during the Mt Lemmon Survey. It was placed on the PCCP as C20NF62. There were pre-discovery images from PanSTARRS on January 25. [MPEC 2020-C111, 2020 February 6]. The comet was at perihelion at 3.4 au in 2019 October. For some reason JPL currently classify it as a Jupiter-family comet.
    2020 BS7 [A/Lemmon]
    The Mt Lemmon Survey discovered an object of 20th magnitude in images taken with the 1.5m reflector on January 19.08. [MPEC 2020-B163, 2020 January 25]. It was placed on the PCCP as C1RWKU2. The object was at perihelion at 0.4 au in 2019 November and has a period of around 5.4 years. JPL classify it as an Apollo asteroid and an NEO.
    2020 BZ12 [A/PanSTARRS]
    PanSTARRS 1 discovered an asteroid in images taken with the 1.8m Ritchey-Chretien on January 19.62. The object, classified by JPL as an Apollo asteroid and an NEO with MOID of 0.08 au, is at perihelion at 0.6 au in 2020 April and has a retrograde orbit with a period of around 20 years. It was placed on the PCCP as P10W6lW. No cometary activity has been detected.
    2020 BU13 [A/PanSTARRS]
    PanSTARRS 1 discovered an asteroid in images taken with the 1.8m Ritchey-Chretien on January 25.30. The object, classified by JPL as an Apollo asteroid and an NEO with MOID of 0.06 au, was at perihelion at 0.1 au in 2019 December and has an orbit with a period of around 4 years. It was placed on the PCCP as P10WTyQ. No cometary activity has been detected.
    2020 EP [A/Lemmon]
    The Mt Lemmon Survey discovered an object of 21st magnitude in images taken with the 1.5m reflector on March 2.44. [MPEC 2020-F03, 2020 March 16]. It was placed on the PCCP as C2AJT22. The object was at perihelion at 2.5 au in 2020 February and has peiodic orbit of around 30 years. JPL classify it as a Centaur.
    2020 F1 (P/Leonard)
    Gregory J Leonard discovered a comet of 20th magnitude in images taken with the Mt Lemmon Survey 1.5m reflector on 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.

    With a published orbit, several researchers looked for pre-discovery observations in archival data, coming up with observations made in 2002 March. 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]


    2020 F2 (ATLAS)
    A 19th magnitude object was discovered in images taken with the 0.5m Schmidt at Haleakala on March 21.62 by the ATLAS (Asteroid Terrestrial-impact Last Alert System) team. The next day it was detected by PanSTARRS, who noted a coma. It was posted on the PCCP as A10kZLv. Prediscovery images from PanSTARRS were found from 2019 May, August and 2020 February. [CBET 4739, MPEC 2020-G04, 2020 April 1]. The comet was at perihelion at 8.8 au in 2022 July.
    2020 F3 (NEOWISE)
    An approximately 17th magnitude comet was discovered from the NEOWISE satellite on March 27.71. It was posted on the PCCP as N00gbay. Several observers confirmed the cometary nature, including John Drummond who showed an image during the BAA webinar on 2019 Y4 on the evening of April 1. [CBET 4740, MPEC 2020-G05, 2020 April 1/2] The object is at perihelion at 0.3 au in 2020 July. The orbit is still uncertain, particularly with regard to the eccentricity, which is either parabolic or of long period.  The absolute magnitude is also uncertain. Michael Mattiazzo notes that the comet already appears to be about 13th magnitude, which implies a significantly brighter absolute magnitude to that used in the CBET.  This would be in line with NEOWISE magnitudes often being fainter than the equivalent visual magnitude.

    The comet is currently a southern hemisphere object but will be poorly placed by the time it comes within visual range prior to perihelion, however observations may be possible in late April and the first half of May. It will move into the SOHO field around June 22, when it may be 6th magnitude.  Post perihelion it moves rapidly into northern skies and might be picked up as a 5th magnitude object in the second week of July. It will fade fairly rapidly but could remain visible until mid August.


    2020 F4 (P/PanSTARRS)
    PanSTARRS 1 discovered a comet in images taken with the 1.8m Ritchey-Chretien on 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.
    2020 F5 (MASTER)
    The MASTER team reported the discovery of a 16th magnitude comet in ATEL 13619 on April 6. The comet was found using the MASTER (Mobile Astronomical System of the Telescope-Robots) auto detection system with the robotic 0.4m f/2.5 reflector at San Juan, Argentina on March 28.25, with images from earlier in March then found in data collected by the system at the SAAO, Sutherland, South Africa. It was confirmed by other observers and formally announced by the MPC and CBAT. [CBET 4745, 4746, MPEC 2020-G73, 2020 April 8]. The comet will reach perihelion at 4.3 au in 2021 March.  It might reach 14th magnitude, but will not be well placed for observation from the UK.
    2020 F6 (PanSTARRS)
    PanSTARRS 1 discovered an object in images taken with the 1.8m Ritchey-Chretien on March 21.61, with a coma being reported the next day. It was placed on the PCCP as P10XLLe. [CBET 4748, MPEC 2020-G74 2020 April 8] The comet was near perihelion at 3.5 au.
    Ephemerides of current comets are available on the CBAT ephemeris page and positions of newly discovered comets are on the NEO confirmation page.
    More information on LINEAR. A list of comets discovered by selected search programs.
    The Northumberland refractor is the telescope that was used in the search for Neptune. It now has a 0.30-m f20 doublet lens which gives a stellar limiting magnitude of around 15 at the zenith on good nights. The Thorrowgood refractor was built in 1864 and has a 0.20-m f14 doublet lens.
    Published by Jonathan Shanklin. Jon Shanklin - jds@ast.cam.ac.uk