C/2020 T2 (Palomar)

For other comets discovered by the Palomar Observatory, see Comet Palomar.

C/2020 T2 (Palomar) is a non-periodic comet with an approximately 5,530-year orbital period around the Sun. It was discovered from the Palomar Observatory on 7 October 2020.^[1]

C/2020 T2 (Palomar)

The comet images by ZTF on 12 May 2021
Discovery[1]
Discovered by	D. A. Duev
Discovery site	Palomar Observatory
Discovery date	7 October 2020
Designations
Alternative designations	CK20T020
Orbital characteristics[2]
Epoch	15 May 2021 (JD 2459349.5)
Observation arc	1,015 days (2.78 years)
Earliest precovery date	11 December 2019
Number of observations	2,755
Aphelion	~620 AU
Perihelion	2.05 AU
Semi-major axis	~310 AU
Eccentricity	0.99343
Orbital period	~5,530 years
Inclination	27.873°
Longitude of ascending node	83.048°
Argument of periapsis	150.38°
Mean anomaly	359.98°
Last perihelion	11 July 2021
Next perihelion	~7550s
TJupiter	1.585
Earth MOID	1.081 AU
Jupiter MOID	1.786 AU
Physical characteristics[3]
Mean diameter	11.05 ± 0.1 km (6.866 ± 0.062 mi)
Comet total magnitude (M1)	9.5
Comet nuclear magnitude (M2)	12.2

Observational history

The comet was first identified by D. A. Duev when he analyzed the photographic plates taken by the Palomar Observatory on 7 October 2020, where he spotted a tail stretching about 5 arcseconds in length.^[1]

Its large perihelion distance of 2.05 AU (307 million km) has enabled numerous follow-up observations to be conducted until 2022.^[2] On 10 January 2021, the comet was 2.59 AU (387 million km; 241 million mi) from Earth, and around magnitude 16.4 in brightness. Between 22 January and 5 July 2021, extensive observations from the Purple Mountain Observatory detected traces of hydrogen cyanide (HCN) gas continuously emanating from its coma.^[4] On 17 May 2021, the comet was located as a 10.5-magnitude object with an outer green coma measuring 10-arcminutes in size near the Messier 3 globular cluster.^[5][6] Around two weeks before perihelion, observations of the comet noted that it lacked a significant dust tail, but there was a strong condensation on its coma, reminiscent of a typical Manx comet,^[7] where near-infrared spectropolarimetry measurements of the comet were also conducted in the same time period.^[8] Post-perihelion observations from the Hissar Observatory between 27 August and 2 September 2021 revealed that the upper estimate of the size of its nucleus is roughly 11.05±0.1 km in diameter.^[3] By October 2021, the comet faded back to an 11th-magnitude object as it moved away from both the Sun and the Earth.^[9]