354P/LINEAR
Hubble Space Telescope image of 354P/LINEAR with dusty impact debris on 2 February 2010
Discovery[1]
Discovered byLINEAR (704)
Discovery date6 January 2010
Designations
Orbital characteristics[3]
Epoch 13 October 2010 (JD 2455482.5)
Aphelion2.58 AU (Q)
Perihelion2.01 AU (q)
2.29 AU (a)
Eccentricity0.1246
3.47 yr
88.9° (M)
Inclination5.25°
320°
2023-Oct-13[4]
133°
Physical characteristics
Dimensions172.4 × 88.8 m[5]
Mean diameter
123.8+33.6
−18.4 m[5]
11.36±0.02 h
Albedounknown
~18-20[1]
21.3±0.6[6]

    354P/LINEAR, provisionally designated P/2010 A2 (LINEAR), is a small main-belt asteroid that was impacted by another asteroid sometime before 2010. It was discovered by the Lincoln Near-Earth Asteroid Research (LINEAR) at Socorro, New Mexico on 6 January 2010. The asteroid possesses a dusty, X-shaped, comet-like debris trail that has remained nearly a decade since impact.[5] This was the first time a small-body collision had been observed; since then, minor planet 596 Scheila has also been seen to undergo a collision, in late 2010. The tail is created by millimeter-sized particles being pushed back by solar radiation pressure.[7][8]

    Overview

    Orbit of P/2010 A2 at the time of its discovery

    P/2010 A2 was discovered on 6 January 2010 by Lincoln Near-Earth Asteroid Research (LINEAR) using a 1-meter (36") reflecting telescope with a CCD camera.[1] It was LINEAR's 193rd comet discovery.[9][10] It has been observed over a 112-day arc of the 3.5 year orbit.[3] It appears to have come to perihelion (closest approach to the Sun) around the start of December 2009,[3] about a month before it was discovered.

    With an aphelion (furthest distance from the Sun) of only 2.6 AU,[3] P/2010 A2 spends all of its time inside of the frostline at 2.7 AU.[11] Beyond the frostline volatile ices are generally more common. Early observations did not detect water vapor or other gases.[12] Within less than a month of its discovery it was doubtful that the tail of P/2010 A2 was generated via active outgassing from sublimation of ices hidden beneath the crust.[13] Early modeling indicated that the asteroid became active in late March 2009, reached maximum activity in early June 2009, and eased activity in early December 2009.[14]

    354P/LINEAR as seen an 8 min photo with a 24" telescope

    Observations with the Hubble Space Telescope[15] and the narrow angle camera on board the Rosetta spacecraft[16] indicate that the dust trail seen was probably created by the impact of a small meter size object on the larger asteroid in February or March 2009, although it cannot be ruled out that the asteroid's rotation increased from solar radiation resulting in a loss of mass that formed a comet-like tail.[17]

    P/2010 A2 is likely about 150 meters (460 feet) in diameter.[12] Even when it was discovered it was suspected of being less than 500 meters in diameter.[18]

    The orbit of P/2010 A2 is consistent with membership in the Flora asteroid family, produced by collisional shattering more than 100 million years ago.[12] The Flora family of asteroids may be the source of the Chicxulub (Cretaceous–Paleogene) impactor, the likely culprit in the extinction of the dinosaurs.[12]

    Debris field

    P/2010 A2 is likely the debris left over from a recent collision between two very small asteroids.
    Surviving fragment

    Surviving fragment seen to the lower left of debris field

    See also

    References

    1. 1 2 3 Marsden, Brian G. (7 January 2010). "MPEC 2010-A32 : COMET P/2010 A2 (LINEAR)". IAU Minor Planet Center. Harvard-Smithsonian Center for Astrophysics. Retrieved 14 January 2010.
    2. ↑ "When is a comet not a comet? Rosetta finds out". ESA News. 13 October 2010. Retrieved 15 October 2010.
    3. 1 2 3 4 "JPL Small-Body Database Browser: P/2010 A2 (LINEAR)" (last observation: 2012-10-14; arc: 2.83 years). Retrieved 3 February 2010.
    4. ↑ JPL Horizons Observer Location: @sun (Perihelion occurs when deldot changes from negative to positive.)
    5. 1 2 3 Kim, Yoonyoung; Ishiguro, Masateru; Lee, Myung Gyoon (June 2017). "New Observational Evidence of Active Asteroid P/2010 A2: Slow Rotation of the Largest Fragment". The Astrophysical Journal Letters. 842 (2): 5. arXiv:1706.03924. Bibcode:2017ApJ...842L..23K. doi:10.3847/2041-8213/aa7944. L23.
    6. ↑ This absolute asteroidal V magnitude has been calculated using comet/asteroid magnitude analysis software "Comet for Windows" from value of R = 23.0±0.5 taken from IAU Circular No. 9109. The mean V-R color index for asteroids is +0.4±0.1.
    7. ↑ HST Sees Evidence of Colliding Asteroids, Astronomy Today, Feb.2, 2010
    8. ↑ Jewitt, David C. "P/2010 A2 (LINEAR): Possible Asteroid Smash". UCLA (Department of Earth and Space Sciences). Retrieved 3 February 2010.
    9. ↑ Hergenrother, Carl W.; The Curious Case of Comet LINEAR, The Transient Sky, 10 January 2010 (1.8-m telescope on Kitt Peak)
    10. ↑ Catalogue of Comet Discoveries, Comethunter.de
    11. ↑ "Glossary of Astronomical Terms (Ice line)". Glossary of Astronomical Terms. Archived from the original on 14 February 2010. Retrieved 20 January 2010.
    12. 1 2 3 4 Harrington, J. D.; Villard, Ray (2 February 2010). "Suspected Asteroid Collision Leaves Trailing Debris". NASA Release : 10-029. Retrieved 3 February 2010.
    13. ↑ Jewitt, David C. "P/2010 A2 (LINEAR): The 5th Main-Belt Comet". UCLA (Department of Earth and Space Sciences). Retrieved 20 January 2010.
    14. ↑ Méndez, Javier (23 July 2010). "Comet P/2010 A2, an Activated Asteroid from the Main Asteroid Belt". Isaac Newton Group of Telescopes (ING). Retrieved 27 July 2010.
    15. ↑ Jewitt, David C.; Weaver, Harold; Agarwal, Jessica; Mutchler, Max; et al. (2010). "A recent disruption of the main-belt asteroid P/2010?A2". Nature. 467 (7317): 817–9. Bibcode:2010Natur.467..817J. doi:10.1038/nature09456. PMID 20944743. S2CID 205222567.
    16. ↑ Snodgrass, Colin; Tubiana, Cecilia; Vincent, Jean-Baptiste; Sierks, Holger; Hviid, Stubbe; Moissl, Richard; Boehnhardt, Hermann; Barbieri, Cesare; et al. (2010). "A collision in 2009 as the origin of the debris trail of asteroid P/2010?A2". Nature. 467 (7317): 814–6. arXiv:1010.2883. Bibcode:2010Natur.467..814S. doi:10.1038/nature09453. PMID 20944742. S2CID 4330570.
    17. ↑ Harrington, J. D.; Weaver, Donna; Jewitt, David C. (13 October 2010). "Hubble Finds that a Bizarre X-Shaped Intruder Is Linked to an Unseen Asteroid Collision". Hubblesite newscenter STScI-2010-34. Retrieved 15 October 2010.
    18. ↑ Shanklin, Jonathan (18 January 2010). "BAA Comet Section : Comets discovered in 2010". Institute of Astronomy (British Astronomical Association). Retrieved 21 January 2010.
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