| C/2017 T2 (PanSTARRS) | |
| Discoverer: | Pan-STARRS |
| Discovery Date: | 2 October 2017 |
| Epoch: | 2458756.5 (30 Sept 2019) |
| Observation Arc: | 3.93 years |
| Obs: | 6896 |
| Orbit: | Oort cloud |
| Aphelion: | ~74000 AU (inbound) ~3000 AU (outbound) |
| Perihelion: | 1.6150 AU |
| Eccentricity: | 0.99971 |
| Period: | ~7 million years (inbound) ~55000 years (outbound) |
| Inclination: | 57.232° |
| Earth Moid: | 1.2abbr=unitNaNabbr=unit |
| Jupiter Moid: | 0.99abbr=unitNaNabbr=unit |
| Last P: | 4 May 2020 |
C/2017 T2 (PanSTARRS) is an Oort cloud comet discovered on 2 October 2017[1] when it was 9.2AU from the Sun. The closest approach to Earth was on 28 December 2019 at a distance of 1.52AU. It came to perihelion (closest approach to the Sun) on 4 May 2020 when it was safe from disintegration at 1.6 AU from the Sun. (Mars is also roughly 1.6 AU from the Sun.)
Comet C/2017 T2 (PanSTARRS) brightened to apparent magnitude 8 and was visible with 50mm binoculars. On 22-24 May 2020, the comet passed near the galaxy pair of Messier 81 and Messier 82, passing less than one degree from the latter.[2] In early June 2020 the comet was near the magnitude 1.8 star Dubhe in Ursa Major.[3]
Based on the light curve of the comet nucleus, it has been estimated that the nucleus has a rotational period of 5.6759 ± 0.0046 h.[4] The comet at perihelion had a water production of 6×1028 molecules/s. Also when observed in CN featured two side jets in June 2020, but they weren't observed one month later.[5] Concentric structures were observed in the inner coma in May 2020, probably created by a jet with rotation axis towards the Earth.[6]
JPL Horizons using an epoch 1950 orbit solution models that C/2017 T2 took millions of years to come from the Oort cloud at a distance of roughly .