astro.wikisort.org - Asteroid

(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 by	NEAT
Discovery site	Haleakala Obs.
Discovery date	19 July 1998
Designations
MPC designation	(12538) 1998 OH
Alternative designations	1998 OH
Minor planet category	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
Semi-major axis	1.5414 AU
Eccentricity	0.4061
Orbital period (sidereal)	1.91 yr (699 days)
Mean anomaly	58.305°
Mean motion	0° 30m 54s / day
Inclination	24.529°
Longitude of ascending node	220.75°
Argument of perihelion	321.72°
Earth MOID	0.0280 AU · 10.9 LD
Physical characteristics
Dimensions	1.663±0.329 km[3][4] 2.06 km (calculated)[5]
Synodic rotation period	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]
Geometric albedo	0.20 (assumed)[5] 0.232±0.116[3][4]
Spectral type	SMASS = S:[1] · S[5]
Absolute magnitude (H)	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

• List of asteroid close approaches to Earth in 2019

Notes

References

External links

• (12538) 1998 OH at the EARN Near-Earth Asteroids Data Base
• Asteroid Lightcurve Database (LCDB), query form (info Archived 16 December 2017 at the Wayback Machine)
• Dictionary of Minor Planet Names, Google books
• Asteroids and comets rotation curves, CdR – Observatoire de Genève, Raoul Behrend
• (12538) 1998 OH at NeoDyS-2, Near Earth Objects—Dynamic Site
  • Ephemeris · Obs prediction · Orbital info · MOID · Proper elements · Obs info · Close · Physical info · NEOCC
• (12538) 1998 OH at ESA–space situational awareness
  • Ephemerides · Observations · Orbit · Physical Properties · Summary
• (12538) 1998 OH at the JPL Small-Body Database
  • Close approach · Discovery · Ephemeris · Orbit diagram · Orbital elements · Physical parameters

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