427P/ATLAS
Periodic comet and active asteroid
From Wikipedia, the free encyclopedia
427P/ATLAS is a periodic comet and an active asteroid with a 5.65-year orbit around the Sun. It is the second comet discovered by the Asteroid Terrestrial-impact Last Alert System after 478P/ATLAS.[8]
Comet 427P/ATLAS photographed from the WIYN Observatory (left) and the Hubble Space Telescope (right).[1] | |
| Discovery[2] | |
|---|---|
| Discovered by | Aren Heinze |
| Discovery site | ATLAS–HKO (T05) |
| Discovery date | 27 September 2017 |
| Designations | |
| P/2017 S5, P/2021 L6 | |
| Orbital characteristics[3][4] | |
| Epoch | 23 November 2017 (JD 2458080.5) |
| Observation arc | 3.89 years |
| Earliest precovery date | 11 September 2017 |
| Number of observations | 438 |
| Aphelion | 4.163 AU |
| Perihelion | 2.178 AU |
| Semi-major axis | 3.171 AU |
| Eccentricity | 0.31304 |
| Orbital period | 5.646 years |
| Inclination | 11.849° |
| 252.39° | |
| Argument of periapsis | 99.944° |
| Mean anomaly | 20.594° |
| Last perihelion | 19 March 2023[5] |
| Next perihelion | 31 October 2028[5] |
| TJupiter | 3.092 |
| Earth MOID | 1.210 AU |
| Jupiter MOID | 1.664 AU |
| Physical characteristics[6][7] | |
Mean radius | 0.45 ± 0.06 km (0.280 ± 0.037 mi) |
| ~1.4 hours | |
| 0.06±0.02 | |
| (V–R) = 0.43±0.05 | |
| Comet total magnitude (M1) | 10.7 |
| Comet nuclear magnitude (M2) | 15.8 |
Orbit
The comet orbits within the main asteroid belt at distances between 2.18 AU (326 million km) and 4.16 AU (622 million km) from the Sun.[3] Studies of its orbital trajectory revealed that it is highly likely a member of the Theobalda collisional family,[9] a group of asteroids formed from a large, shattered parent body about 7 million years ago.[10] The main-belt comets 455P/PANSTARRS and 483P/PANSTARRS also belong to this group.
Physical characteristics
Like most of the main-belt comets, the observed activity from 427P/ATLAS is driven by the sublimation of water ice on its surface, which its mass loss rate is estimated to be about ~5.0±3.0 kg/sec-1 during its perihelion in 2017.[11]
Photometric observations from the Lisnyky Observatory showed that this comet has some notable instability of color, likely caused by the injection of fresh material to its coma.[6]
Observations from the Hubble Space Telescope in 2019 had determined that its nucleus has an effective radius of 0.450±0.060 km, assuming a geometric albedo of 0.06±0.02.[7][11]