311P/PanSTARRS
{{Short description|Comet discovered in 2013}}
{{For|other comets of the same name|List of Pan-STARRS discoveries}}
{{Use dmy dates|date=April 2020}}
{{Infobox planet
| name = 311P/PanSTARRS
| background = #FFE0C2
| image = Asteroid P2013 P5 v2.jpg
| image_scale =
| caption = P/2013 P5 (PanSTARRS) as captured by the Hubble Space Telescope
| discoverer = Bryce T. Bolin using Pan-STARRS
| discovered = 27 August 2013
| alt_names = P/2013 P5 (PANSTARRS)
| mp_category = {{Ubl
| asteroid
}}
| epoch = 16 November 2013 (JD 2456612.5)
| uncertainty = 0
| observation_arc = 13.13 yr (4,797 d)
| earliest_precovery_date = 17 January 2005
| aphelion = 2.4411 AU
| perihelion = 1.9362 AU
| time_periastron = 2024-Jan-01
| semimajor = 2.1885 AU
| eccentricity = 0.11530
| period = 3.24 yr (1182.575d)
| avg_speed = 0.3044°/d
| mean_anomaly = 314.07°
| inclination = 4.9685°
| asc_node = 279.29°
| arg_peri = 144.26°
| mean_diameter = ~{{convert|480|m|sp=us}}
| density = {{convert|3300|±|200|kg/m3|g/cm3|disp=out}}
| escape_velocity = ~{{val|0.240|u=m/s}}
| rotation =
| spectral_type =
| abs_magnitude =
}}
311P/PanSTARRS, also known as P/2013 P5 (PanSTARRS), is an active asteroid (object with asteroid-like orbit but with comet-like visual characteristics) discovered by Bryce T. Bolin using the Pan-STARRS telescope on 27 August 2013.{{cite news|title=When is a comet not a comet?|url=http://www.spacetelescope.org/news/heic1320/#1|publisher=Spacetelescope|date=7 November 2013}} Observations made by the Hubble Space Telescope revealed that it had six comet-like tails.{{cite web|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}} 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.
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.{{cite web|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}} 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.{{cite news|title=Hubble astronomers observe bizarre six-tailed asteroid|url=http://www.spacetelescope.org/news/heic1320/|publisher=Spacetelescope|date=7 November 2013}} The Hubble Space Telescope continued to track the object through 11 February 2014. 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.
==Possible satellite==
On April 19, 2018, observations based on light curvature suggested a possible satellite around 311P/PANSTARRS approaching 200 meters.{{Cite web|url=http://www.johnstonsarchive.net/astro/asteroidmoonsq.html|title=Other reports of asteroid/TNO companions}} If true this would be one of the few minor planets designated as a comet known to harbor a satellite.
Exploration
{{main|Tianwen-2}}
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. 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.{{Cite web |last=Jones |first=Andrew |date=13 January 2023 |title=Tianwen-2: China’s Near-Earth asteroid and comet double-header |url=https://www.planetary.org/articles/tianwen-2-chinas-near-earth-asteroid-and-comet-double-header |access-date=2025-02-10 |website=The Planetary Society |language=en}}
See also
- 354P/LINEAR (P/2010 A2)
- Yarkovsky–O'Keefe–Radzievskii–Paddack effect (aka YORP effect)
References
{{reflist
| refs =
|last1=Jewitt |first1=D.
|last2=Agarwal |first2=J.
|last3=Weaver |first3=H.
|last4=Mutchler |first4=M.
|last5=Larson |first5=S.
|year=2013
|title=The Extraordinary Multi-Tailed Main-Belt Comet P/2013 P5
|journal=The Astronomical Journal
|volume= 778|issue= 1|pages=L21
|arxiv=1311.1483
|bibcode=2013ApJ...778L..21J
|doi=10.1088/2041-8205/778/1/L21
|s2cid=67795816
}}
|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
|access-date=2013-11-09}}
|title=311P/PANSTARRS Orbit
|url=http://www.minorplanetcenter.net/db_search/show_object?object_id=311P
|publisher=Minor Planet Center
|access-date=2014-09-13}}
|title = CBET #3639 : P/2013 P5 (PANSTARRS)
|url = https://ui.adsabs.harvard.edu/abs/2013CBET.3639....1B/abstract
|display-authors = etal
|first = B.
|last = Bolin
|journal = Central Bureau Electronic Telegrams
|publisher = Central Bureau for Astronomical Telegrams
|date = 27 August 2013
|volume = 3639
|page = 1
|bibcode = 2013CBET.3639....1B
|access-date = 27 August 2013
|archive-url = https://web.archive.org/web/20200921090806/https://ui.adsabs.harvard.edu/abs/2013CBET.3639....1B/abstract
|archive-date = 21 September 2020
|url-status = live}}
|title=Horizons Batch for 311P/PANSTARRS on 2024-Jan-01
|publisher=JPL Horizons
|type=Perihelion occurs when rdot flips from negative to positive
|url=https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%27311P%27&START_TIME=%272024-Jan-01%27&STOP_TIME=%272024-Jan-02%27&STEP_SIZE=%271%20hour%27&QUANTITIES=%2719%27
|accessdate=2022-08-29}} (JPL#29/Soln.date: 2021-Apr-15)
}}
External links
- [http://remanzacco.blogspot.it/2013/11/the-multi-tailed-main-belt-comet-p2013.html The Multi-Tailed Main-Belt Comet P/2013 P5] (Remanzacco Observatory : 8 November 2013)
- [http://www.slate.com/blogs/bad_astronomy/2013/11/08/asteroid_tales_p_2013_p5_blows_out_six_tails.html Confused Asteroid Sprouts Tails… Six of Them!] (Phil Plait : 8 November 2013)
- [http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=p%2F2013%20p5;orb=1;cov=0;log=0;cad=0#orb Orbit diagram from JPL Small-Body Database]
{{Comets}}
{{2013 in space}}
{{Authority control}}
{{DEFAULTSORT:PANSTARRS, 311P}}