| Discoverer | Bryce T. Bolin |
|---|---|
| Discovery site | Haleakala Observatory (Pan-STARRS) |
| Discovery date | 27 August 2013 |
| Mpc name | P/2013 P5 |
| Epoch | 21 November 2025 (JD 2461000.5) |
| Observation arc | 20.29 years |
| Obs | 271 |
| Earliest precovery date | 17 January 2005 |
| Perihelion | 1.936 AU |
| Aphelion | 2.441 AU |
| Semimajor | 2.189 AU |
| Eccentricity | 0.1154 |
| Period | 3.238 years |
| Avg speed | 0.304°/d |
| Inclination | 4.971° |
| Asc node | 279.17° |
| Arg peri | 144.32° |
| Mean | 209.72° |
| Tjup | 3.661 |
| Earth moid | 0.949 AU |
| Jupiter moid | 2.818 AU |
| Mean diameter | ~0.48 km (0.30 mi)[1] |
| Escape velocity | ~0.240 m/s[1] |
| Rotation | ≥ 5.4 hours[2] |
| Density | 3.3 ± 0.2 g/cm3[1] |
| Albedo | 0.29 ± 0.09[3] |
| M 1 | 18.98 ± 0.10[3] |
| Last p | 1 January 2024 |
| Next p | 30 March 2027 |
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.[4][5] Observations made by the Hubble Space Telescope revealed that it had six comet-like tails.[6] 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.[1] 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,[a] radiation pressure from the Sun then stretched the dust into streams.[6]
Precovery images from the Sloan Digital Sky Survey from 2005 were found, showing negligible cometary activity in 2005.[citation needed]
Physical characteristics
The asteroid has a radius of about 240 m (790 ft).[1] The first images taken by Pan-STARRS revealed that the object had an unusual appearance: asteroids generally appear as small points of light, but P/2013 P5 was identified as a fuzzy-looking object by astronomers.[5] The multiple tails were observed by the Hubble Space Telescope on 10 September 2013, Hubble later returned to the asteroid on 23 September, its appearance had totally changed. It looked as if the entire structure had swung around.[5] The Hubble Space Telescope continued to track the object through 11 February 2014.[7] The comet-like appearance has resulted in the asteroid being named as a comet. The object has a low orbital inclination and always stays outside the orbit of Mars.[8]
Possible satellite
On 19 April 2018, observations based on light curvature suggested a possible satellite around 311P/PANSTARRS approaching 200 meters.[9] If true this would be one of the few minor planets designated as a comet known to harbor a satellite.
Exploration
The Tianwen-2 spacecraft is planned to get in orbit around 311P/PanSTARRS in the mid-2030s. It was launched on 28 May 2025 and it will first visit and take samples from asteroid 469219 Kamoʻoalewa from late 2026 to early 2027.[10] After returning them to Earth, it will use its close encounter with Earth for a gravity assist towards 311P/PanSTARRS. When it arrives there, it will get into orbit and conduct a remote sensing study.[11]
See also
- 354P/LINEAR, formerly known as P/2010 A2 (LINEAR)
- Yarkovsky–O'Keefe–Radzievskii–Paddack effect (YORP effect)
Notes
- ^ "She calculated that dust-ejection events occurred on April 15, July 18, July 24, Aug. 8, Aug. 26 and Sept. 4"
References
- ^ D. C. Jewitt; J. Agarwal; H. Weaver; M. Mutchler; S. Larson (2013). "The Extraordinary Multi-Tailed Main-Belt Comet P/2013 P5". The Astrophysical Journal Letters. 778 (1): 21–25. arXiv:1311.1483. Bibcode:2013ApJ...778L..21J. doi:10.1088/2041-8205/778/1/L21. S2CID 67795816
- ^ D. C. Jewitt; H. Weaver; M. Mutchler et al. (2018). "The Nucleus of Active Asteroid 311P/(2013 P5) PanSTARRS". The Astronomical Journal. 155 (6): 231–242. arXiv:1804.05897. Bibcode:2018AJ....155..231J. doi:10.3847/1538-3881/aabdee
- ^ D. C. Jewitt; J. Agarwal; H. Weaver; M. Mutchler; S. Larson (2015). "Episodic Ejection from Active Asteroid 311P/PanSTARRS". The Astrophysical Journal. 798 (2): 109–121. arXiv:1410.8573. Bibcode:2015ApJ...798..109J. doi:10.1088/0004-637X/798/2/109
- ^ B. T. Bolin; L. Denneau; M. Micheli et al. (2013-08-27). "Comet P/2013 P5 (PanSTARRS)". Central Bureau for Astronomical Telegrams. 3639. D. W. Green et al. (ed.). Bibcode:2013CBET.3639....1B
- ^ D. C. Jewitt & N. Guttridge (2013-11-07). "When is a comet not a comet?". esahubble.org. European Space Agency. Retrieved 2025-11-12.
- ^ J. D. Harrington (2013-11-07). "NASA's Hubble Sees Asteroid Spouting Six Comet-Like Tails". nasa.gov. NASA. Retrieved 2025-11-12.
- ^ "311P/PanSTARRS Orbit". Minor Planet Center. Retrieved 2014-09-13.
- ^ "311P/PanSTARRS – JPL Small-Body Database Lookup". ssd.jpl.nasa.gov. Jet Propulsion Laboratory. Retrieved 2013-11-09.
- ^ W. R. Johnston (2025-10-04). "Other reports of asteroid/TNO companions". Johnston's Archive. Retrieved 2025-11-12.
- ^ A. Jones (2025-05-28). "China launches Tianwen 2 mission to snag samples of a near-Earth asteroid (video)". Space.com. Retrieved 2025-11-12.
- ^ A. Jones (2023-01-13). "Tianwen-2: China’s Near-Earth asteroid and comet double-header". The Planetary Society. Retrieved 2025-02-10.
External links
- 311P/PanSTARRS at Seiichi Yoshida's website
- The Multi-Tailed Main-Belt Comet P/2013 P5 (Remanzacco Observatory : 8 November 2013)
- Confused Asteroid Sprouts Tails... Six of Them! (Phil Plait : 8 November 2013)