C/2020 M3 (ATLAS)

DEPARTED

Type: Periodic Perihelion date: 25 October 2020 Perihelion distance (q): 1.3 Aphelion distance (Q) : 52.4 Period (years): 139 Eccentricity (e): 0.95 Inclination (i): 23.5 JPL orbit diagram COBS lightcurve 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 27 June 2020. It was posted on the PCCP as A10nHge and subsequently noted as cometary by several astrometrists. The comet was at perihelion at 1.3 au in October 2020 and has a period of around 140 years. It subsequently briefly appeared on the PCCP as A10r0Kz on 23 September. It brightened more rapidly than expected, possibly following a linear form light curve, and peaked at around 8th magnitude in early November. Observations (VEMag = visual equivalent magnitude) Date 10x10 mag Error VEmag Coma ' 13-Sep-20 14.88 0.02 12.6 1.9 21-Sep-20 14.51 0.04 12.5 1.5 12-Oct-20 13.72 0.03 11.6 1.7 26-Oct-20 13.31 0.03 10.1 4.3 08-Nov-20 12.84 0.01 7.6 8.8 17-Nov-20 12.76 0.01 7.5 10.9 21-Nov-20 12.75 0.03 7.4 14.1 06-Dec-20 13.02 0.02 7.4 12.8 14-Dec-20 13.58 0.01 8.5 10.7 16-Dec-20 13.66 0.02 8.2 10.3 10-Jan-21 15.26 0.04 10.4 5.8 19-Jan-21 15.82 0.02 11.4 4.5 07-Feb-21 16.74 0.03 13.1 2.8 11-Feb-21 13.3 1.9 04-Mar-21 18.1 0.4 02-Apr-21 18.2 0.4 10-Apr-21 18.4 0.4 04-May-21 18.4 0.4