(457175) 2008 GO98

(457175) 2008 GO98, provisional designation 2008 GO98 with cometary number 362P, is a Hildian asteroid and rare main-belt comet from the outermost regions of the asteroid belt, approximately 15 kilometers (9 miles) in diameter. It was discovered on 8 April 2008, by astronomers of the Spacewatch program at Kitt Peak National Observatory near Tucson, Arizona, in the United States.[1] The presumably carbonaceous body has a rotation period of 10.7 hours.[5]

(457175) 2008 GO98
Discovery [1]
Discovered bySpacewatch
Discovery siteKitt Peak National Obs.
Discovery date8 April 2008
Designations
(457175) 2008 GO98
2008 GO98 · 362P
main-belt · (outer) [2]
main-belt comet [3][4]
Hilda [1][5]
Orbital characteristics [2]
Epoch 4 December 2015 (JD 2457360.5)
Uncertainty parameter 0
Observation arc16.05 yr (5,862 d)
Aphelion5.0787 AU
Perihelion2.8506 AU
3.9646 AU
Eccentricity0.2810
7.89 yr (2,883 d)
327.18°
0° 7m 29.64s / day
Inclination15.569°
192.61°
53.287°
Jupiter MOID0.3592 AU
TJupiter2.9260
Physical characteristics
Mean diameter
5.5–24.7 km (est.)[6]
14.64 h (calculated)[5]
10.74±0.01 h[5][lower-alpha 1]
0.057 (assumed)[5]
C (assumed)[5]
12.9[1][2][5]
15.1[4]

    Orbit and classification

    2008 GO98 is classified as a member of the dynamical Hilda group,[5] as well as a main-belt comet that shows clear cometary activity,[3][6] which has also been described as a "quasi Hilda comet".[4] Orbital backward integration suggests that it might have been a centaur or trans-Neptunian object that ended its dynamical evolution as a quasi Hilda comet.[4]

    It orbits the Sun in the outer asteroid belt at a distance of 2.9–5.1 AU once every 7 years and 11 months (2,883 days; semi-major axis of 3.96 AU). Its orbit has an eccentricity of 0.28 and an inclination of 16° with respect to the ecliptic.[2] The body's observation arc begins with a precovery taken by the Sloan Digital Sky Survey in October 2001, more than 5 years prior to its official discovery observation by Spacewatch.[1]

    2008 GO98 has a Jupiter Tisserand's parameter (TJ) of 2.926,[2] just below Jewitt's threshold of 3, which serves as a distinction between the main-belt asteroids (TJ larger than 3) and the Jupiter-family comets (TJ between 2 and 3).[7]

    Numbering and naming

    This minor planet was numbered by the Minor Planet Center on 16 February 2016 (M.P.C. 98587).[8] As of 2020, it has not been named.[1]

    Physical characteristics

    2008 GO98 is an assumed C-type asteroid.[5]

    Rotation period

    In August 2017, a rotational lightcurve of 2008 GO98 was obtained from photometric observations by American astronomer Brian Warner at the Palmer Divide Station (U82) in California. Lightcurve analysis gave a rotation period of 10.74±0.01 hours with a small brightness amplitude of 0.12 magnitude (U=2).[5][lower-alpha 1]

    Diameter and albedo

    The Collaborative Asteroid Lightcurve Link assumes a standard albedo for a carbonaceous body of 0.057 and calculates a diameter of 14.64 kilometers based on an absolute magnitude of 12.9.[5] Other estimates, taking into account several published magnitude measurements and a large range of albedo assumptions, estimate a diameter range of 5.5 to 24.7 kilometers.[6]

    Notes
    1. Lightcurve plot of (457175) 2008 GO98, by B. D Warner, at CS3 (2017). Rotation period 10.74±0.01 hours with a brightness amplitude of 0.12±0.02 mag. Quality Code is 2. Summary figures at the LCDB.

    References
    1. "457175 (2008 GO98)". Minor Planet Center. Retrieved 12 December 2020.
    2. "JPL Small-Body Database Browser: 457175 (2008 GO98)" (2017-11-02 last obs.). Jet Propulsion Laboratory. Retrieved 15 September 2018.
    3. "MPEC 2017-N50 : COMETARY ACTIVITY IN (457175) 2008 GO98". Minor Planet Center. Retrieved 14 February 2018.
    4. Gil-Hutton, R.; García-Migani, E. (May 2016). "Comet candidates among quasi-Hilda objects" (PDF). Astronomy and Astrophysics. 590: 5. Bibcode:2016A&A...590A.111G. doi:10.1051/0004-6361/201628184. Retrieved 14 February 2018.
    5. "LCDB Data for (457175)". Asteroid Lightcurve Database (LCDB). Retrieved 14 February 2018.
    6. "362P/2008 GO98". Asteroid-Analytics. 21 July 2017. Retrieved 14 February 2018.
    7. David Jewitt. "The Tisserand Parameter". Retrieved 15 September 2018.
    8. "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 14 February 2018.

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