C/2017 T2 (PanSTARRS)
Oort cloud comet From Wikipedia, the free encyclopedia
C/2017 T2 (PanSTARRS) is an Oort cloud comet discovered on 2 October 2017[4] when it was 9.2 AU (1.38 billion km) from the Sun. The closest approach to Earth was on 28 December 2019 at a distance of 1.52 AU (227 million km). It came to perihelion (closest approach to the Sun) on 4 May 2020[2] when it was safe from disintegration at 1.6 AU from the Sun. (Mars is also roughly 1.6 AU from the Sun.)
| |
| Discovery | |
|---|---|
| Discovered by | Pan-STARRS |
| Discovery date | 2 October 2017 |
| Orbital characteristics[1][2] | |
| Epoch | 2458756.5 (30 Sept 2019) |
| Observation arc | 3.93 years |
| Number of observations | 6896 |
| Orbit type | Oort cloud |
| Aphelion | ~74000 AU (inbound) ~3000 AU (outbound) |
| Perihelion | 1.6150 AU |
| Eccentricity | 0.99971 |
| Orbital period | ~7 million years (inbound) ~55000 years (outbound) |
| Inclination | 57.232° |
| Last perihelion | 4 May 2020 |
| Earth MOID | 1.2 AU (180 million km; 470 LD) |
| Jupiter MOID | 0.99 AU (148 million km; 390 LD) |
| Physical characteristics[3] | |
| Dimensions | 1.0–1.8 km (0.62–1.12 mi) |
Mean diameter | 1.4 km (0.87 mi) |
Observational history
Comet C/2017 T2 (PanSTARRS) brightened to apparent magnitude 8 and was visible with 50mm binoculars.[5][6] 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.[7] In early June 2020 the comet was near the magnitude 1.8 star Dubhe in Ursa Major.[8]
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.[9] 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.[10] Concentric structures were observed in the inner coma in May 2020, probably created by a jet with rotation axis towards the Earth.[11]
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 74,000 AU (1.2 ly).[1]
C/2017 T2 (right) passing near Messier 81 and Messier 82 on May 22, 2020
C/2017 T2 (centre) passing near the Double Cluster on January 23, 2020
References
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