C/2020 M3 (ATLAS)

For other comets discovered by the Asteroid Terrestrial-impact Last Alert System, see Comet ATLAS.

Comet C/2020 M3 (ATLAS) is a Halley-type comet that passed within 0.358 AU (53.6 million km) from Earth on 14 November 2020.^[5] It is one of many comets discovered by the Asteroid Terrestrial-impact Last Alert System (ATLAS).

C/2020 M3 (ATLAS)

Comet C/2020 M3 (ATLAS) photographed on 21 November 2020
Discovery[1]
Discovery site	ATLAS–MLO (T08)
Discovery date	27 June 2020
Designations
Alternative designations	CK20M030
Orbital characteristics[2]
Epoch	26 November 2020 (JD 2459179.5)
Observation arc	348 days
Number of observations	2,344
Aphelion	52.367 AU
Perihelion	1.268 AU
Semi-major axis	26.817 AU
Eccentricity	0.95371
Orbital period	138.87 years
Inclination	23.474°
Longitude of ascending node	71.250°
Argument of periapsis	328.45°
Mean anomaly	0.223°
Last perihelion	25 October 2020
Next perihelion	~2159[3]
TJupiter	1.460
Earth MOID	0.327 AU
Jupiter MOID	0.886 AU
Physical characteristics[2][4]
Comet total magnitude (M1)	14.6
Apparent magnitude	6.9 (2020 apparition)

Observational history

The comet was first discovered on 27 June 2020 as an asteroid-like object by the 0.5 m (1.6 ft)-telescope at the Mauna Loa Observatory in Hawaii as part of the ATLAS survey.^[1] Observations in August 2020 revealed that the comet was about 4–5 magnitudes brighter than predicted.^[6]

By 8 November 2020, the comet was seen a few degrees east of the Horseshoe and Orion Nebulae.^[7] It passed closest to Earth at a distance of 0.358 AU (53.6 million km) on 14 November.^[5] By 25 November, the comet was passing through the constellation Taurus, near the Crab Nebula's position.^[8]

Physical characteristics

Observations conducted by the TRAPPIST-North telescope at the Oukaïmeden Observatory in Morocco were used to determine the comet's dust production and chemical composition.^[9] It was determined that the comet had a typical composition compared to other comets, without any depletion of carbon-chain elements from its coma.^[10][11]