311P/PanSTARRS
Comet 311P/PanSTARRS imaged by the Hubble Space Telescope on 10–23 September 2013 | |
| Discovery | |
|---|---|
| Discovered by | Bryce T. Bolin |
| Discovery site | Haleakala Observatory (Pan-STARRS) |
| Discovery date | 27 August 2013 |
| Designations | |
| P/2013 P5 | |
| Orbital characteristics | |
| Epoch | 29 April 2017 (JD 2457872.5) |
| Observation arc | 20.29 years |
| Earliest precovery date | 17 January 2005 |
| Number of observations | 272 |
| Aphelion | 2.442 AU |
| Perihelion | 1.936 AU |
| Semi-major axis | 2.189 AU |
| Eccentricity | 0.11567 |
| Orbital period | 3.238 years |
| Avg. orbital speed | 0.304°/d |
| Inclination | 4.966° |
| 279.26° | |
| Argument of periapsis | 143.99° |
| Mean anomaly | 337.88° |
| Last perihelion | 1 January 2024 |
| Next perihelion | 30 March 2027 |
| TJupiter | 3.661 |
| Earth MOID | 0.949 AU |
| Jupiter MOID | 2.818 AU |
| Physical characteristics | |
Mean diameter | ~0.48 km (0.30 mi) |
Mean density | 3.3±0.2 g/cm3 |
| ~0.240 m/s | |
| ≥ 5.4 hours | |
| 0.29±0.09 | |
| Comet total magnitude (M1) | 18.98±0.10 |
311P/PanSTARRS, also known as P/2013 P5 (PanSTARRS), is an active asteroid and Encke-type comet discovered by Bryce T. Bolin using the Pan-STARRS telescope on 27 August 2013. Observations made by the Hubble Space Telescope revealed that it had six comet-like tails. The tails are suspected to be streams of material ejected by the asteroid as a result of a rubble pile asteroid spinning fast enough to remove material from it. This is similar to 331P/Gibbs, which was found to be a quickly-spinning rubble pile as well.
Three-dimensional models constructed by Jessica Agarwal of the Max Planck Institute for Solar System Research in Lindau, Germany, showed that the tails could have formed by a series of periodic impulsive dust-ejection events, radiation pressure from the Sun then stretched the dust into streams.
Precovery images from the Sloan Digital Sky Survey from 2005 were found, showing negligible cometary activity in 2005.