C/2024 L5 (ATLAS)

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

C/2024 L5 (ATLAS) is a comet that was discovered on 14 June 2024 as A117uUD by the Asteroid Terrestrial-impact Last Alert System (ATLAS), South Africa, Sutherland. It reached perihelion on 10 March 2025 at 3.432 AU (513.4 million km) from the Sun.^[4][5]

C/2024 L5 (ATLAS)

Discovery
Discovered by	L. Denneau R. Siverd J. Tonry H. Weiland
Discovery site	ATLAS South Africa
Discovery date	14 June 2024
Designations
Alternative designations	A117uUD[1]
Orbital characteristics[2][3]
Epoch	22 July 2024 (JD 2460513.5)
Observation arc	103 days
Number of observations	247
Orbit type	Hyperbolic
Perihelion	3.4320 AU
Eccentricity	1.03743
Inclination	166.573°
Longitude of ascending node	139.166°
Argument of periapsis	290.521°
Last perihelion	10 March 2025
Earth MOID	2.46255 AU
Jupiter MOID	0.00497 AU
Comet total magnitude (M1)	6.7

It is the second known Solar System comet to become interstellar after experiencing a planetary encounter.^[5][1] C/1980 E1 (Bowell) reached a hyperbolic trajectory after an encounter with Jupiter on 9 December 1980.^[6][7] C/2024 L5 experienced a very close encounter at 0.0048 AU with Saturn on 24 January 2022.^[2][5][1] C/2024 L5 could be a former retrograde, inactive centaur.^[8] The receding velocity of C/2024 L5 when entering interstellar space will be 2.8 km/s, moving towards the constellation of Triangulum.^[8]

Orbit

JPL Horizons shows an outbound eccentricity greater than 1^[3] so it will leave the Solar System eventually as C/1980 E1 (Bowell) is doing, but prior to its flyby to Saturn its eccentricity was 0.88.^[1]

See also

• List of Solar System objects by greatest aphelion
• List of hyperbolic comets
• List of non-periodic comets
• List of periodic comets
• 1I/ʻOumuamua
• 2I/Borisov
• C/1980 E1 (Bowell)