9175 Graun

9175 Graun
Discovery [1]
Discovered by H. E. Holt
Discovery site Palomar Obs.
Discovery date 29 July 1990
Designations
MPC designation 9175 Graun
Named after
 Ken Graun
(author, astronomy)[2]
1990 OO2 · 1975 CL
1980 BB1 · 1986 WS4
1991 XL2
main-belt
Eunomia [3] · Maria [4]
Orbital characteristics [1]
Epoch 16 February 2017 (JD 2457800.5)
Uncertainty parameter 0
Observation arc 41.75 yr (15,251 days)
Aphelion 2.9668 AU
Perihelion 2.2339 AU
2.6003 AU
Eccentricity 0.1409
4.19 yr (1,532 days)
112.46°
0° 14m 6.36s / day
Inclination 15.068°
330.03°
353.31°
Physical characteristics
Dimensions 7.929±0.142 km[5][6]
10.35±0.71 km[7]
10.53 km (calculated)[3]
20 h[4]
25.8±0.5 h[8]
0.183±0.027[7]
0.21 (assumed)[3]
0.308±0.042[5][6]
S [3]
12.2[1][3] · 12.25±0.38[9] · 12.4[7][5]

    9175 Graun, provisional designation 1990 OO2, is an asteroid from the middle region of the asteroid belt, approximately 10 kilometers in diameter. It was discovered by American astronomer Henry E. Holt at the U.S. Palomar Observatory in California, on 29 July 1990.[10]

    The Collaborative Asteroid Lightcurve Link (CALL) classifies the asteroid as a member of the Eunomia family, a large group of S-type asteroids and the most prominent family in the intermediate main-belt, while, based on its concurring orbital elements, Alvarez-Candal from the Universidad Nacional de Córdoba and others, group the asteroid into the Maria family, which is named after its namesake, the asteroid 170 Maria.[4] It is an old-type asteroid family, about (3±1)×109 years old, located near the area of a 3:1 resonances with Jupiter that supplies near-Earth asteroids to the inner Solar System (also see Kirkwood gap). It is estimated that every 100 million years, about 37 to 75 Maria asteroids larger than 1 kilometer become near-Earth objects.[8]

    The stony asteroid orbits the Sun at a distance of 2.2–3.0 AU once every 4 years and 2 months (1,532 days). Its orbit has an eccentricity of 0.14 and an inclination of 15° with respect to the ecliptic.[1] The first observation was made at the Karl Schwarzschild Observatory in 1975, extending the asteroid's observation arc by 15 years prior to its discovery.[10]

    In January 2013, a rotational light-curve for this asteroid was obtained from photometric observations taken at Korean and other observatories. It rendered a rotation period of 25.8±0.5 hours with a brightness variation of 0.16 in magnitude (U=2+).[8] The measurement supersedes a previous observation from South America that gave a shorter period of 20 hours and an amplitude of 0.2 in magnitude (U=1).[4]

    According to the surveys carried out by the Japanese Akari satellite and NASA's Wide-field Infrared Survey Explorer (WISE) with its subsequent NEOWISE mission, the asteroid measures 10.4 and 7.9 kilometers, respectively. The discrepancy in the determined diameters is due to a divergent measurement of the asteroid's albedo, as the higher a body's reflectivity (albedo) the lower its diameter, for a given absolute brightness (magnitude). While WISE finds a very high albedo of 0.31, results from the Akari satellite gave a relatively low albedo of 0.18.[7][5][6] Moreover, CALL assumes an intermediate albedo of 0.21, a typical value for stony asteroids, and calculates a diameter of 10.5 kilometers.[3]

    The minor planet was named in honor of American amateur astronomer and publisher, Ken Graun (b. 1955), author of two books on astronomy, owner of "Ken Press" and the website What's Out tonight?, bringing astronomy to the broader public including children.[2][11] Naming citation was published on 9 March 2001 (M.P.C. 42358).[12]

    References

    1. 1 2 3 4 "JPL Small-Body Database Browser: 9175 Graun (1990 OO2)" (2016-11-10 last obs.). Jet Propulsion Laboratory. Retrieved 4 December 2016.
    2. 1 2 Schmadel, Lutz D. (2007). Dictionary of Minor Planet Names – (9175) Graun. Springer Berlin Heidelberg. p. 682. ISBN 978-3-540-00238-3. Retrieved 24 July 2016.
    3. 1 2 3 4 5 6 "LCDB Data for (9175) Graun". Asteroid Lightcurve Database (LCDB). Retrieved 24 July 2016.
    4. 1 2 3 4 Alvarez-Candal, Alvaro; Duffard, René; Angeli, Cláudia A.; Lazzaro, Daniela; Fernández, Silvia (December 2004). "Rotational lightcurves of asteroids belonging to families". Icarus. 172 (2): 388–401. Bibcode:2004Icar..172..388A. doi:10.1016/j.icarus.2004.06.008. Retrieved 1 January 2016.
    5. 1 2 3 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:1109.6407Freely accessible. Bibcode:2011ApJ...741...90M. doi:10.1088/0004-637X/741/2/90. Retrieved 24 July 2016.
    6. 1 2 3 Masiero, Joseph R.; Mainzer, A. K.; Grav, T.; Bauer, J. M.; Cutri, R. M.; Dailey, J.; et al. (November 2011). "Main Belt Asteroids with WISE/NEOWISE. I. Preliminary Albedos and Diameters". The Astrophysical Journal. 741 (2): 20. arXiv:1109.4096Freely accessible. Bibcode:2011ApJ...741...68M. doi:10.1088/0004-637X/741/2/68. Retrieved 4 December 2016.
    7. 1 2 3 4 Usui, Fumihiko; Kuroda, Daisuke; Müller, Thomas G.; Hasegawa, Sunao; Ishiguro, Masateru; Ootsubo, Takafumi; et al. (October 2011). "Asteroid Catalog Using Akari: AKARI/IRC Mid-Infrared Asteroid Survey". Publications of the Astronomical Society of Japan. 63 (5): 1117–1138. Bibcode:2011PASJ...63.1117U. doi:10.1093/pasj/63.5.1117. Retrieved 24 July 2016.
    8. 1 2 3 Kim, M.-J.; Choi, Y.-J.; Moon, H.-K.; Byun, Y.-I.; Brosch, N.; Kaplan, M.; et al. (March 2014). "Rotational Properties of the Maria Asteroid Family" (PDF). The Astronomical Journal. 147 (3): 15. arXiv:1311.5318Freely accessible. Bibcode:2014AJ....147...56K. doi:10.1088/0004-6256/147/3/56. Retrieved 24 January 2016.
    9. ↑ 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:1506.00762Freely accessible. Bibcode:2015Icar..261...34V. doi:10.1016/j.icarus.2015.08.007. Retrieved 24 July 2016.
    10. 1 2 "9175 Graun (1990 OO2)". Minor Planet Center. Retrieved 24 July 2016.
    11. ↑ "What's out tonight?". Ken Press. January 2016. Retrieved 1 January 2016.
    12. ↑ "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 24 July 2016.

    External links

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