C/2019 L3 (ATLAS)

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

Comet ATLAS, provisional designation C/2019 L3, is a distant non-periodic comet that reached perihelion at a distance of 3.55 AU (531 million km) in January 2022. It is one of many comets discovered by the Asteroid Terrestrial-impact Last Alert System (ATLAS).

C/2019 L3 (ATLAS)

Discovery[1]
Discovery site	ATLAS–HKO (T05)
Discovery date	10 June 2019
Orbital characteristics[2]
Epoch	10 October 2021 (JD 2459497.5)
Observation arc	5.97 years
Number of observations	6,499
Perihelion	3.554 AU
Eccentricity	1.00141
Inclination	48.364°
Longitude of ascending node	290.79°
Argument of periapsis	171.61°
Mean anomaly	–0.007°
Last perihelion	9 January 2022
TJupiter	1.553
Earth MOID	2.576 AU
Jupiter MOID	1.654 AU
Physical characteristics[2]
Mean radius	7.9 km (4.9 mi)[3]
Spectral type	(B–V) = 0.75±0.06[4] (V–R) = 1.04±0.09[4] (R–I) = 0.21±0.05[4]
Comet total magnitude (M1)	5.5
Apparent magnitude	8.4 (2022 apparition)[5]

Physical characteristics

Narrowband observations conducted at the TRAPPIST-North survey in January 2022 reveal that C/2019 L3 appear to be a very dusty comet, with a high dust-to-gas ratio relative to other comets.^[6] Data analysis in 2024 concluded that activity within the comet may had begun while it was at least 13 AU (1.9 billion km) from the Sun, indicating the possibility that the comet could remain active until at least the second half of 2026.^[3]

The nucleus of the comet is estimated to have a minimum radius of around 7.9 km (4.9 mi).^[3]