(52768) 1998 OR2

(52768) 1998 OR2
Discovery [1][2]
Discovered by NEAT
Discovery site Haleakala Obs.
Discovery date 24 July 1998
Designations
MPC designation (52768) 1998 OR2
1998 OR2
Apollo · NEO · PHA [1][2]
Orbital characteristics [1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc 30.32 yr (11,076 days)
Aphelion 3.7428 AU
Perihelion 1.0167 AU
2.3798 AU
Eccentricity 0.5728
3.67 yr (1,341 days)
103.81°
0° 16m 6.6s / day
Inclination 5.8796°
27.064°
174.45°
Earth MOID 0.0157 AU · 6.1 LD
Physical characteristics
Mean diameter
 2.15 km (calculated)[3]
3.198±0.006 h[4]
4.112±0.002h[5]
0.20 (assumed)[3]
L [6] · S (assumed)[3]
15.7[3] · 15.7±0.1[4] · 15.8[2] · 15.9[1] · 16.15±0.10[7]

    (52768) 1998 OR2, provisional designation 1998 OR2, is an asteroid on an eccentric orbit, classified as near-Earth object and potentially hazardous asteroid of the Apollo group, approximately 2 kilometers in diameter. It was discovered on 24 July 1998, by astronomers of the NEAT program at the Haleakala Observatory, Hawaii.[2] It is one of the brightest and therefore largest potentially hazardous asteroids known to exist.[8]

    Orbit and classification

    1998 OR2 is a member of the dynamical Apollo group,[1][2] which are Earth-crossing asteroids. Apollo asteroids are the largest subgroup of near-Earth objects.

    It orbits the Sun at a distance of 1.0–3.7 AU once every 3 years and 8 months (1,341 days; semi-major axis of 2.38 AU). Its orbit has a high eccentricity of 0.57 and an inclination of 6° with respect to the ecliptic. With its sufficiently large aphelion, this asteroid is also classified as a Mars-crosser, crossing the orbit of the Red Planet at 1.66 AU.[1]

    The body's observation arc begins with a precovery published by the Digitized Sky Survey an taken at the Siding Spring Observatory on June 1986, or more than one year prior to its official discovery observation at Haleakala.[2]

    Close approaches

    With an absolute magnitude of approximately 15.8,[2] 1998 OR2 is one of the brightest and presumably largest known potentially hazardous asteroid (see PHA-list).[8] It has an Earth minimum orbital intersection distance of 0.0157 AU (2,350,000 km), which translates into 6.1 lunar distances (LD).[1] On 16 April 2079, this asteroid will make a close near-Earth encounter at a nominal distance of 0.0118 AU (4.6 LD), and pass the Moon at 0.009 AU (3.58 LD).[1]

    Physical characteristics

    According to observations by the NASA IRTF telescope during the ExploreNEOs Warm Spitzer program, 1998 OR2 is a rather rare L-type asteroid.[6]

    Rotation period

    In 2009, rotational lightcurves of 1998 OR2 were obtained from photometric observations by astronomers in Salvador, Brazil, and during the Lowell Observatory Near-Earth Asteroid Photometric Survey (NEAPS). Lightcurve analysis gave a rotation period of 3.198 and 4.112 hours with a brightness amplitude of 0.29 and 0.16 magnitude, respectively (U=2/2+).[4][5]

    Diameter and albedo

    The Collaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20 and calculates a diameter of 2.15 kilometers based on an absolute magnitude of 15.7.[3]

    Naming

    As of 2018, this minor planet has not been named.[2]

    References

    1. 1 2 3 4 5 6 7 8 "JPL Small-Body Database Browser: 52768 (1998 OR2)" (2017-10-26 last obs.). Jet Propulsion Laboratory. Retrieved 24 January 2018.
    2. 1 2 3 4 5 6 7 8 "52768 (1998 OR2)". Minor Planet Center. Retrieved 24 January 2018.
    3. 1 2 3 4 5 "LCDB Data for (52768)". Asteroid Lightcurve Database (LCDB). Retrieved 24 January 2018.
    4. 1 2 3 Betzler, Alberto Silva; Novaes, Alberto Brum (October 2009). "Photometric Observations of 1998 OR2, 1999 AQ10, and 2008 TC3". The Minor Planet Bulletin. 36 (4): 145–147. Bibcode:2009MPBu...36..145B. ISSN 1052-8091. Retrieved 24 January 2018.
    5. 1 2 Koehn, Bruce W.; Bowell, Edward G.; Skiff, Brian A.; Sanborn, Jason J.; McLelland, Kyle P.; Pravec, Petr; et al. (October 2014). "Lowell Observatory Near-Earth Asteroid Photometric Survey (NEAPS) - 2009 January through 2009 June". The Minor Planet Bulletin. 41 (4): 286–300. Bibcode:2014MPBu...41..286K. ISSN 1052-8091. Retrieved 24 January 2018.
    6. 1 2 Thomas, Cristina A.; Emery, Joshua P.; Trilling, David E.; Delbó, Marco; Hora, Joseph L.; Mueller, Michael (January 2014). "Physical characterization of Warm Spitzer-observed near-Earth objects" (PDF). Icarus. 228: 217–246. arXiv:1310.2000. Bibcode:2014Icar..228..217T. doi:10.1016/j.icarus.2013.10.004. Retrieved 24 January 2018.
    7. ↑ Veres, Peter; Jedicke, Robert; Fitzsimmons, Alan; Denneau, Larry; Granvik, Mikael; Bolin, Bryce; et al. (November 2015). "Absolute magnitudes and slope parameters for 250,000 asteroids observed by Pan-STARRS PS1 - Preliminary results". Icarus. 261: 34–47. arXiv:1506.00762. Bibcode:2015Icar..261...34V. doi:10.1016/j.icarus.2015.08.007. Retrieved 24 January 2018.
    8. 1 2 "List of the Potentially Hazardous Asteroids (PHAs)". Minor Planet Center. Retrieved 24 January 2018.
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