C/2020 T2 (Palomar)

Lore & Background

The comet was first identified by D. A. Duev when he analyzed photographic plates taken by the Palomar Observatory on 7 October 2020, spotting a tail stretching about 5 arcseconds in length. Its large perihelion distance of 2.05 AU enabled numerous follow-up observations until 2022. On 10 January 2021, the comet was 2.59 AU from Earth and around magnitude 16.4. 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. On 17 May 2021, the comet was a 10.5-magnitude object with an outer green coma measuring 10 arcminutes near the Messier 3 globular cluster. Around two weeks before perihelion, observations noted it lacked a significant dust tail but had a strong condensation on its coma, reminiscent of a typical Manx comet; near-infrared spectropolarimetry measurements were also conducted in that period. Post-perihelion observations from the Hissar Observatory between 27 August and 2 September 2021 revealed that the upper estimate of its nucleus size is roughly 11.05±0.1 km in diameter. By October 2021, the comet faded back to an 11th-magnitude object as it moved away from both the Sun and Earth.

Reader's Guide

C/2020 T2 (Palomar) holds significance as a non-periodic comet with a very long orbital period of about 5,530 years, making its current apparition a rare event. Its large perihelion distance of 2.05 AU allowed sustained observation over nearly two years, providing a valuable dataset. The detection of hydrogen cyanide gas from its coma over several months in 2021 offered insights into its volatile composition. The comet's lack of a significant dust tail near perihelion, combined with a strong condensation in its coma, placed it in the category of Manx comets, which are thought to be primitive bodies from the outer Solar System. The near-infrared spectropolarimetry measurements conducted around that time added further data on its physical properties. Post-perihelion observations from the Hissar Observatory provided an upper estimate of its nucleus diameter at roughly 11 km, contributing to understanding the size distribution of such long-period comets. The comet's passage near the Messier 3 globular cluster in May 2021 also made it a target for amateur and professional astronomers alike.

Did You Know?

• The comet was discovered by D. A. Duev from photographic plates taken at Palomar Observatory on 7 October 2020.
• Its orbital period around the Sun is approximately 5,530 years.
• Between January and July 2021, hydrogen cyanide gas was continuously detected emanating from its coma.
• Post-perihelion observations estimated its nucleus diameter at roughly 11.05±0.1 km.