BAA Comet Section : Comets discovered in 2020

Created 2020 January 16

  • A/2020 A1 (A/NEOWISE)
  • 2020 A2 (Iwamoto)

  • 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 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.

    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 near perihelion at 1.0 au according to the very preliminary orbit on the CBET. 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. There is as yet no orbit from JPL. The preliminary 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.
    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 -