(12538) 1998 OH

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(12538) 1998 OH
Discovery [1]
Discovered by NEAT
Discovery site Haleakala Obs.
Discovery date 19 July 1998
MPC designation (12538) 1998 OH
1998 OH
NEO · Apollo · PHA[1][2]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc 25.96 yr (9,483 days)
Aphelion 2.1674 AU
Perihelion 0.9155 AU
1.5414 AU
Eccentricity 0.4061
1.91 yr (699 days)
0° 30m 54s / day
Inclination 24.529°
Earth MOID 0.0280 AU · 10.9 LD
Physical characteristics
Dimensions 1.663±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]
SMASS = S: [1] · S[5]
15.8[1][5] · 16.1[4]

(12538) 1998 OH is a stony asteroid, classified as near-Earth object and potentially hazardous asteroid of the Apollo group, approximately 1.8 kilometers 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]

Orbit and classification[edit]

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[edit]

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[edit]

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

Rotation period[edit]

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][a][b]

Diameter and albedo[edit]

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 albedoof 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]

Numbering and naming[edit]

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


  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


  1. ^ a b c d e f g h i "JPL Small-Body Database Browser: 12538 (1998 OH)" (2017-09-26 last obs.). Jet Propulsion Laboratory. Retrieved 31 October 2017. 
  2. ^ a b c d "12538 (1998 OH)". Minor Planet Center. Retrieved 31 October 2017. 
  3. ^ a b c 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:1109.6400Freely accessible. Bibcode:2011ApJ...743..156M. doi:10.1088/0004-637X/743/2/156. Retrieved 31 October 2017. 
  4. ^ a b c d Mainzer, A.; Grav, T.; Masiero, J.; Hand, E.; Bauer, J.; Tholen, D.; et al. (November 2011). "NEOWISE Studies of Spectrophotometrically Classified Asteroids: Preliminary Results" (PDF). The Astrophysical Journal. 741 (2): 25. arXiv:1109.6407Freely accessible. Bibcode:2011ApJ...741...90M. doi:10.1088/0004-637X/741/2/90. Retrieved 31 October 2017. 
  5. ^ a b c d e f g "LCDB Data for (12538)". Asteroid Lightcurve Database (LCDB). Retrieved 31 October 2017. 
  6. ^ a b c 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. Retrieved 31 October 2017. 
  7. ^ a b 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. Retrieved 31 October 2017. 
  8. ^ a b 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. Retrieved 31 October 2017. 
  9. ^ a b 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. Retrieved 31 October 2017. 
  10. ^ "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 24 February 2018. 

External links[edit]