C/2020 A2 (Iwamoto)

For the 2013 and 2018 comets of the same name, see C/2013 E2 (Iwamoto) and C/2018 Y1 (Iwamoto).

Comet Iwamoto, formally designated as C/2020 A2 is a faint non-periodic comet that was observed between January and April 2020. As of 2025^[update], it is the fourth and most recent comet discovered by Japanese astronomer, Masayuki Iwamoto.^[6][a]

C/2020 A2 (Iwamoto)

Comet C/2020 A2 (Iwamoto) photographed from the Zwicky Transient Facility on 19 February 2020.
Discovery[1][2]
Discovered by	Masayuki Iwamoto
Discovery site	Tokushima, Japan
Discovery date	8 January 2020
Designations
Alternative designations	CK20A020,[2] IF033[3]
Orbital characteristics[4]
Epoch	23 February 2020 (JD 2458902.5)
Observation arc	104 days
Number of observations	529
Aphelion	~2,120 AU
Perihelion	0.978 AU
Semi-major axis	~1,060 AU
Eccentricity	0.99908
Orbital period	~34,500 years
Inclination	120.75°
Longitude of ascending node	286.38°
Argument of periapsis	68.209°
Mean anomaly	0.0013°
Last perihelion	8 January 2020
TJupiter	–0.622
Earth MOID	0.312 AU
Jupiter MOID	1.129 AU
Physical characteristics
Comet total magnitude (M1)	15.1
Comet nuclear magnitude (M2)	17.2
Apparent magnitude	9.6[5] (2020 apparition)

Observational history

Masayuki Iwamoto reported a new 14th-magnitude object with cometary features on the night of 8 January 2020, which was moving gradually north within the constellation Ophiuchus.^[3][b] Nearly five days later, Gennadiy Borisov confirmed the existence of Iwamoto's new comet, reporting that it has a diffuse coma about 40 arcseconds in diameter.^[2] Additional observations from the Xingming Observatory, Magdalena Ridge Observatory, and other sites between 10 and 14 January 2020 reveal that the comet does not have a tail at the time.^[7]