9298 Geake

9298 Geake, provisional designation 1985 JM, is a Mitidika asteroid from the central regions of the asteroid belt, approximately 12 kilometers in diameter. It was discovered on 15 May 1985, by American astronomer Edward Bowell at Lowell Observatory's Anderson Mesa Station near Flagstaff, Arizona, United States.[13] The asteroid was named for British astronomer John E. Geake.[2]

9298 Geake
Discovery [1]
Discovered byE. Bowell
Discovery siteAnderson Mesa Stn.
Discovery date15 May 1985
Designations
(9298) Geake
Named after
John E. Geake
(British astronomer)[2]
1985 JM · 1994 VN2
main-belt · (middle) [3]
Mitidika [4]
Orbital characteristics [1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc60.89 yr (22,241 days)
Aphelion3.3406 AU
Perihelion1.8041 AU
2.5724 AU
Eccentricity0.2987
4.13 yr (1,507 days)
240.52°
0° 14m 20.04s / day
Inclination12.113°
211.83°
120.10°
Physical characteristics
Dimensions6.50 km (calculated)[3]
11.54±0.27 km[5]
11.73±3.10 km[6]
12.40±4.66 km[7]
12.68±4.23 km[8]
14.040±0.983 km[9][10]
38.29±0.02 h[11][lower-alpha 1]
0.033±0.008[9][10]
0.049±0.002[5]
0.05±0.02[6]
0.050±0.026[8]
0.05±0.06[7]
0.20 (assumed)[3]
S (assumed)[3]
13.20[6] · 13.3[1][3] · 13.36[8] · 13.42[7] · 13.59±1.39[12] · 13.6[5][9]

    Orbit and classification

    Geake has been identified as a member of the Mitidika family, a dispersed asteroid family of carbonaceous C-type asteroids. The family is named after 2262 Mitidika (diameter of 9 km) and consists of 653 known members, the largest ones being 404 Arsinoë (95 km) and 5079 Brubeck (17 km).[4][14]:23[lower-alpha 2]

    The asteroid orbits the Sun in the central main-belt at a distance of 1.8–3.3 AU once every 4 years and 2 months (1,507 days). Its orbit has an eccentricity of 0.30 and an inclination of 12° with respect to the ecliptic.[1] It was first observed on a precovery taken at Palomar Observatory in May 1956, extending the body's observation arc by 29 years prior to its official discovery observation at Anderson Mesa.[13]

    Physical characteristics

    Lightcurves

    In August 2006, a rotational lightcurve of Geake was obtained from photometric observations by American astronomer Brian Warner at his Palmer Divide Observatory (716) in Colorado. Lightcurve analysis gave a rotation period of 38.29 hours with a brightness variation of 0.78 magnitude (U=2).[11][lower-alpha 1] While not being a slow rotator, it has a longer than average rotation, which lies normally between 2 and 20 hours. The body's high brightness amplitude of 0.78 magnitude also indicates that it has a non-spheroidal shape.

    Diameter and albedo

    According to the surveys carried out by the Japanese Akari satellite and NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Geake measures between 11.54 and 14.040 kilometers in diameter and its surface has a low albedo between 0.033 and 0.05.[5][6][7][8][9][10]

    Contrary to the results obtained by the space-based observatories, the Collaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20, derived from the family's namesake,[lower-alpha 2] and consequently calculates a much shorter diameter of 6.50 kilometers based on an absolute magnitude of 13.3, as the higher a body's reflectivity the smaller its diameter for a given brightness.[3]

    Naming

    This minor planet was named after British astronomer John E. Geake (1925–1998), who invented the direct-reading linear refractometer, which was used by the Cassini–Huygens space probe.[2] The official naming citation was published by the Minor Planet Center on 26 July 2000 (M.P.C. 41029).[15]

    Notes
    1. Lightcurve plot of 9298 Geake with a rotation period 38.29±0.02 hours with a brightness amplitude of 0.78±0.03 by B. D. Warner at the Palmer Divide Observatory (2006). Summary figures at LCDB
    2. While the members of the Mitidika family have been characterized by Nesvorný (2014) as carbonaceous C-type asteroids with low albedos around 0.06, the family's namesake, 2262 Mitidika, is a much more reflective body with a measured albedo of 0.208, typically associated with stony S-type asteroids.

    References
    1. "JPL Small-Body Database Browser: 9298 Geake (1985 JM)" (2017-03-30 last obs.). Jet Propulsion Laboratory. Retrieved 22 July 2017.
    2. Schmadel, Lutz D. (2007). "(9298) Geake". Dictionary of Minor Planet Names – (9298) Geake. Springer Berlin Heidelberg. p. 687. doi:10.1007/978-3-540-29925-7_7452. ISBN 978-3-540-00238-3.
    3. "LCDB Data for (9298) Geake". Asteroid Lightcurve Database (LCDB). Retrieved 22 July 2017.
    4. "Asteroid 9298 Geake – Nesvorny HCM Asteroid Families V3.0". Small Bodies Data Ferret. Retrieved 27 October 2019.
    5. 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 17 October 2019. (online, AcuA catalog p. 153)
    6. Nugent, C. R.; Mainzer, A.; Masiero, J.; Bauer, J.; Cutri, R. M.; Grav, T.; et al. (December 2015). "NEOWISE Reactivation Mission Year One: Preliminary Asteroid Diameters and Albedos". The Astrophysical Journal. 814 (2): 13. arXiv:1509.02522. Bibcode:2015ApJ...814..117N. doi:10.1088/0004-637X/814/2/117. Retrieved 22 July 2017.
    7. Nugent, C. R.; Mainzer, A.; Bauer, J.; Cutri, R. M.; Kramer, E. A.; Grav, T.; et al. (September 2016). "NEOWISE Reactivation Mission Year Two: Asteroid Diameters and Albedos". The Astronomical Journal. 152 (3): 12. arXiv:1606.08923. Bibcode:2016AJ....152...63N. doi:10.3847/0004-6256/152/3/63. Retrieved 22 July 2017.
    8. Masiero, Joseph R.; Mainzer, A. K.; Grav, T.; Bauer, J. M.; Cutri, R. M.; Nugent, C.; et al. (November 2012). "Preliminary Analysis of WISE/NEOWISE 3-Band Cryogenic and Post-cryogenic Observations of Main Belt Asteroids". The Astrophysical Journal Letters. 759 (1): 5. arXiv:1209.5794. Bibcode:2012ApJ...759L...8M. doi:10.1088/2041-8205/759/1/L8. Retrieved 22 July 2017.
    9. 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.
    10. 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:1109.4096. Bibcode:2011ApJ...741...68M. doi:10.1088/0004-637X/741/2/68. Retrieved 22 July 2017.
    11. Warner, Brian D. (March 2007). "Asteroid Lightcurve Analysis at the Palmer Divide Observatory - June-September 2006". The Minor Planet Bulletin. 34 (1): 8–10. Bibcode:2007MPBu...34....8W. ISSN 1052-8091. Retrieved 22 July 2017.
    12. 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 22 July 2017.
    13. "9298 Geake (1985 JM)". Minor Planet Center. Retrieved 22 July 2017.
    14. Nesvorný, D.; Broz, M.; Carruba, V. (December 2014). Identification and Dynamical Properties of Asteroid Families. Asteroids IV. pp. 297–321. arXiv:1502.01628. Bibcode:2015aste.book..297N. doi:10.2458/azu_uapress_9780816532131-ch016. ISBN 9780816532131.
    15. "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 22 July 2017.

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