(12538) 1998 OH

(12538) 1998 OH is a stony asteroid, classified as near-Earth object and potentially hazardous asteroid of the Apollo group, approximately 1.8 kilometers (1.1 miles) in diameter. It was discovered on 19 July 1998, by astronomers of the Near-Earth Asteroid Tracking program at the Haleakala Observatory in Hawaii, United States.[2] In 2019, the asteroid came within about 73 lunar distances of Earth.

(12538) 1998 OH
Discovery [1]
Discovered byNEAT
Discovery siteHaleakala Obs.
Discovery date19 July 1998
Designations
(12538) 1998 OH
1998 OH
NEO · Apollo · PHA [1][2]
Orbital characteristics [1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc25.96 yr (9,483 days)
Aphelion2.1674 AU
Perihelion0.9155 AU
1.5414 AU
Eccentricity0.4061
1.91 yr (699 days)
58.305°
0° 30m 54s / day
Inclination24.529°
220.75°
321.72°
Earth MOID0.0280 AU · 10.9 LD
Physical characteristics
Dimensions1.663±0.329 km[3][4]
2.06 km (calculated)[5]
2.58±0.001 h[6]
2.582±0.001 h[6]
5.088±0.004 h[7]
5.154 h[5]
5.191±0.002 h[8]
5.833±0.005 h[9]
0.20 (assumed)[5]
0.232±0.116[3][4]
SMASS = S: [1] · S [5]
15.8[1][5] · 16.1[4]

    Numbering and naming

    This minor planet was numbered by the Minor Planet Center on 23 November 1999.[10] As of 2018, it has not been named.[2]

    Orbit and classification

    1998 OH is a member of the Apollo group of asteroids, which are Earth-crossing asteroids. They are the largest group of near-Earth objects with approximately 10 thousand known members.

    It orbits the Sun at a distance of 0.9–2.2 AU in 1 year and 11 months (699 days). Its orbit has an eccentricity of 0.41 and an inclination of 25° with respect to the ecliptic.[1] The body's observation arc begins with a precovery taken at Palomar Observatory in October 1991, more than 7 years prior to its official discovery observation at Haleakala.[2]

    Close approaches

    The asteroid has an Earth minimum orbital intersection distance of 0.0280 AU (4,190,000 km; 2,600,000 mi), which corresponds to 10.9 lunar distances and makes it a potentially hazardous asteroid due to its sufficiently large size.[1] It will pass close to Earth in 2042 and 2132, at a distance of 0.0292 AU and 0.0317 AU, respectively.[1]

    Physical characteristics

    In the SMASS classification, 1998 OH is a common stony S-type asteroid.[1]

    Rotation period

    In 2014, several rotational lightcurves of 1998 OH were obtained from photometric observations by American astronomer Brian Warner at the Palmer Divide Station in California, by the Spanish amateur astronomer group OBAS, and by astronomers of the EURONEAR lightcurve NEO survey. Lightcurve analysis gave a rotation period of 5.154 hours with an alternative period solution of 2.58 hours, or half the period. The asteroid's brightness amplitude is rather low with a maximum between 0.11 and 0.20 magnitude, which is indicative for a spherical rather than elongated shape (U=3/3/2-/3/2/2).[5][6][7][8][9][lower-alpha 1][lower-alpha 2]

    Diameter and albedo

    According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, 1998 OH measures 1.663 kilometers in diameter and its surface has an albedo of 0.232.[3][4] The Collaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20 and calculates a diameter of 2.06 kilometers based on an absolute magnitude of 15.8.[5]

    See also

    Notes
    1. Lightcurve plot of (12538) by Brian Warner (2014) at the Center for Solar System Studies (CS3), with rotation period 5.833±0.005 hours with a brightness amplitude of 0.12±0.02 mag. Quality Code of 2. Summary figures for (12538) at LCDB
    2. Lightcurve plot of (12538) by Brian Warner (2016) at the Center for Solar System Studies (CS3), with rotation period 5.154±0.002 hours with a brightness amplitude of 0.20 mag. Quality Code of 3. Summary figures for (12538) at LCDB

    References
    1. "JPL Small-Body Database Browser: 12538 (1998 OH)" (2017-09-26 last obs.). Jet Propulsion Laboratory. Retrieved 31 October 2017.
    2. "12538 (1998 OH)". Minor Planet Center. Retrieved 31 October 2017.
    3. Mainzer, A.; Grav, T.; Bauer, J.; Masiero, J.; McMillan, R. S.; Cutri, R. M.; et al. (December 2011). "NEOWISE Observations of Near-Earth Objects: Preliminary Results". The Astrophysical Journal. 743 (2): 17. arXiv:1109.6400. Bibcode:2011ApJ...743..156M. doi:10.1088/0004-637X/743/2/156.
    4. Mainzer, A.; Grav, T.; Masiero, J.; Hand, E.; Bauer, J.; Tholen, D.; et al. (November 2011). "NEOWISE Studies of Spectrophotometrically Classified Asteroids: Preliminary Results". The Astrophysical Journal. 741 (2): 25. arXiv:1109.6407. Bibcode:2011ApJ...741...90M. doi:10.1088/0004-637X/741/2/90.
    5. "LCDB Data for (12538)". Asteroid Lightcurve Database (LCDB). Retrieved 31 October 2017.
    6. Vaduvescu, O.; Macias, A. Aznar; Tudor, V.; Predatu, M.; Galád, A.; Gajdos, S.; et al. (August 2017). "The EURONEAR Lightcurve Survey of Near Earth Asteroids". Earth. 120 (2): 41–100. Bibcode:2017EM&P..120...41V. doi:10.1007/s11038-017-9506-9. hdl:10316/80202.
    7. Lozano, Juan; Flores, Angel; Mas, Vicente; Fornas, Gonzalo; Rodrigo, Onofre; Brines, Pedro; et al. (April 2017). "Seven Near-Earth Asteroids at Asteroids Observers (OBAS) - MPPD: 2016 June-November". The Minor Planet Bulletin. 44 (2): 108–111. Bibcode:2017MPBu...44..108L. ISSN 1052-8091.
    8. Warner, Brian D. (April 2017). "Near-Earth Asteroid Lightcurve Analysis at CS3-Palmer Divide Station: 2016 October-December". The Minor Planet Bulletin. 44 (2): 98–107. Bibcode:2017MPBu...44...98W. ISSN 1052-8091.
    9. Warner, Brian D. (April 2015). "Near-Earth Asteroid Lightcurve Analysis at CS3-Palmer Divide Station: 2014 October-December". The Minor Planet Bulletin. 42 (2): 115–127. Bibcode:2015MPBu...42..115W. ISSN 1052-8091.
    10. "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 24 February 2018.
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