(392741) 2012 SQ31

(392741) 2012 SQ31, provisional designation 2012 SQ31, is a sub-kilometer Florian asteroid from the inner regions of the asteroid belt, approximately 700 meters (2,300 feet) in diameter. It was originally considered a trans-Neptunian object and lost minor planet during 2004–2012. The date of the official discovery was later set to 27 December 2009, and credited to astronomers of the Spacewatch program conducted at the Kitt Peak National Observatory near Tucson, Arizona, in the United States.[1]

(392741) 2012 SQ31
Discovery[1][2]
Discovered bySpacewatch
Discovery siteKitt Peak National Obs.
Discovery date11 August 2004 / 27 December 2009
Designations
(392741) 2012 SQ31
2012 SQ31 · 2004 PR107
2009 YS20
main-belt · (inner)
Flora[3]
Orbital characteristics[4]
Epoch 23 March 2018 (JD 2458200.5)
Uncertainty parameter 0
Observation arc14.22 yr (5,193 d)
Aphelion2.5806 AU
Perihelion1.9412 AU
2.2609 AU
Eccentricity0.1414
3.40 yr (1,242 d)
208.16°
0° 17m 23.64s / day
Inclination3.8552°
77.991°
317.17°
Physical characteristics
Mean diameter
0.69 km (est. at 0.24)[5]
0.24 (assumed)[3]
18.0[4]

    Orbit and classification

    2012 SQ31 a member of the Flora family (402),[3] a giant asteroid family and the largest family of stony asteroids in the main-belt.[6]: 23  It orbits the Sun in the inner asteroid belt at a distance of 1.9–2.6 AU once every 3 years and 5 months (1,242 days; semi-major axis of 2.26 AU). Its orbit has an eccentricity of 0.14 and an inclination of 4° with respect to the ecliptic.[4] The body's observation arc begins with a precovery taken at Haleakala-AMOS, Hawaii, in December 2005, four years prior to its official discovery observation.[1]

    Trans-Neptunian object

    On 11 August 2004, the asteroid was already observed as 2004 PR107 by astronomers at the Cerro Tololo Inter-American Observatory in Chile,[2] but became a lost minor planet until 2012 due to a lack of follow-up observations. During this time, and with only two observations taken on the same day, it was thought to be a trans-Neptunian object with a semi-major axis of 46 AU.[2][7] Michael Brown listed it as a likely a dwarf planet on his website with an estimated diameter of 555 kilometers based on an absolute magnitude of 4.6 and an assumed albedo of 0.09.[8]

    In 2009, the lost asteroid was observed again as 2009 YS20, but was not identified at the time as being related to 2004 PR107. In 2012, it was finally rediscovered under its principal designation, reclassified as a small main-belt asteroid, and numbered two years later (see below).[1]

    Physical characteristics

    2012 SQ31 has been characterized as a member of the Flora family,[3] which are stony S-type asteroids with albedo typically around 0.24, corresponding to that of the family's parent body, 8 Flora.[6]: 23  Based on a generic magnitude-to-diameter conversion, 2012 SQ31 measures 690 meters for an absolute magnitude of 18.0 and an assumed albedo of 0.24.[5] As of 2018, no rotational lightcurve has been obtained from photometric observations. The asteroid's rotation period, poles and shape remain unknown.[4]

    Numbering and naming

    This minor planet was numbered by the Minor Planet Center on 15 April 2014 (M.P.C. 87941).[9] As of 2018, it has not been named.[1]

    See also

    References
    1. "392741 (2012 SQ31)". Minor Planet Center. Retrieved 3 March 2018.
    2. "MPEC 2004-R15 : 2003 QF113, 2004 OJ14, 2004 PR107, 2004 PS107, 2004 PT107". IAU Minor Planet Center. 4 September 2004. Retrieved 3 March 2018. (K04PA7R)
    3. "Asteroid (392741) 2012 SQ31 – Nesvorny HCM Asteroid Families V3.0". Small Bodies Data Ferret. Retrieved 27 October 2019.
    4. "JPL Small-Body Database Browser: 392741 (2012 SQ31)" (2017-02-22 last obs.). Jet Propulsion Laboratory. Retrieved 3 March 2018.
    5. "Asteroid Size Estimator". CNEOS NASA/JPL. Retrieved 12 November 2017.
    6. Nesvorný, D.; Broz, M.; Carruba, V. (December 2014). "Identification and Dynamical Properties of Asteroid Families". Asteroids IV. pp. 297–321. arXiv:1502.01628. Bibcode:2015aste.book..297N. doi:10.2458/azu_uapress_9780816532131-ch016. ISBN 9780816532131. S2CID 119280014.
    7. "392741 (2012 SQ31 = 2004 PR107)". JPL Small-Body Database Browser. Archived from the original on 13 December 2012. Retrieved 22 June 2012.
    8. Brown, Mike. "How many dwarf planets are there in the outer solar system?". California Institute of Technology. Archived from the original on 18 October 2011. Retrieved 22 June 2012.
    9. "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 3 March 2018.
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