| mass =
| density = 3300±200 kg m3 [1]
| surface_grav =
| escape_velocity = ~{{convert|0.240|m|sp=us}} per second
| rotation =
| spectral_type =
| abs_magnitude =
| albedo =
| single_temperature =
}}311P/PANSTARRS also known as P/2013 P5 (PANSTARRS) is an asteroid (or main-belt comet) discovered by the Pan-STARRS telescope on 27 August 2013.[2] Observations made by the Hubble Space Telescope revealed that it had six comet-like tails.[3] 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,{{refn|"She calculated that dust-ejection events occurred on April 15, July 18, July 24, Aug. 8, Aug. 26 and Sept. 4"}} radiation pressure from the sun then stretched the dust into streams.[3]
Precovery images from the Sloan Digital Sky Survey from 2005 were found, showing negligible cometary activity in 2005.
Characteristics
The asteroid has a radius of about {{convert|240|m|sp=us}}.[ 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.[4] 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.[11] 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.[1]]
See also
- P/2010 A2
- Yarkovsky–O'Keefe–Radzievskii–Paddack effect (aka YORP effect)
References
1. ^{{cite web |url=http://www.spacetelescope.org/static/archives/releases/science_papers/heic1320a.pdf |title=The Extraordinary Multi-Tailed Main-Belt Comet P/2013 P5 |publisher=Spacetelescope |format=PDF }}
2. ^{{cite news|title=When is a comet not a comet?|url=http://www.spacetelescope.org/news/heic1320/#1|publisher=Spacetelescope|date=7 November 2013}}
3. ^1 {{cite journal|title=NASA's Hubble Sees Asteroid Spouting Six Comet-Like Tails|url=http://hubblesite.org/newscenter/archive/releases/2013/52/text/|publisher=Hubblesite|date=7 November 2013|accessdate=}}
4. ^{{cite journal|title=When is a comet not a comet?|url=http://sci.esa.int/hubble/53140-when-is-a-comet-not-a-comet-heic1320/|publisher=ESA|date=7 November 2013}}
5. ^{{cite news|title=Hubble astronomers observe bizarre six-tailed asteroid|url=http://www.spacetelescope.org/news/heic1320/|publisher=Spacetelescope|date=7 November 2013}}
6. ^1 2 {{cite web |type=2013-11-07 last obs |title=JPL Small-Body Database Browser: P/2013 P5 (PANSTARRS) |url=http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2013P5 |accessdate=2013-11-09}}
7. ^1 {{cite web |title=311P/PANSTARRS Orbit |url=http://www.minorplanetcenter.net/db_search/show_object?object_id=311P |publisher=Minor Planet Center |accessdate=2014-09-13}}