1197 Rhodesia

1197 Rhodesia, provisional designation 1931 LD, is a dark background asteroid from the outer regions of the asteroid belt, approximately 48 kilometers (30 miles) in diameter. It was discovered on 9 June 1931, by South African astronomer Cyril Jackson at the Union Observatory in Johannesburg.[1] The likely C-type asteroid has a rotation period of 16.1 hours.[10] It was named for Rhodesia, a former British colony and unrecognised state, which is now Zimbabwe.[13]

1197 Rhodesia
Shape model of Rhodesia from its lightcurve
Discovery[1]
Discovered byC. Jackson
Discovery siteJohannesburg Obs.
Discovery date9 June 1931
Designations
(1197) Rhodesia
Named after
Rhodesia
(former state in southern Africa)
1931 LD · 1925 AC
1970 HL
main-belt[1][2] · (outer)
background[3][4]
Orbital characteristics[2]
Epoch 23 March 2018 (JD 2458200.5)
Uncertainty parameter 0
Observation arc93.36 yr (34,098 d)
Aphelion3.5511 AU
Perihelion2.2215 AU
2.8863 AU
Eccentricity0.2303
4.90 yr (1,791 d)
323.09°
0° 12m 3.6s / day
Inclination12.985°
255.74°
277.16°
Physical characteristics
Dimensions48.0 km × 48.0 km[3]
Mean diameter
47.50±3.4 km[5]
47.741±0.163 km[6][7]
48.92±0.98 km[8]
16.060±0.006 h[9]
0.070[6]
0.075[8]
0.0783[5]
B–V = 0.740±030[2][3]
C (assumed)[10]
10.00[5][8]
10.18[6][10][11][12]
10.2[1][2]

    Orbit and classification

    Rhodesia is a non-family asteroid from the main belt's background population.[3][4] It orbits the Sun in the outer asteroid belt at a distance of 2.2–3.6 AU once every 4 years and 11 months (1,791 days; semi-major axis of 2.89 AU). Its orbit has an eccentricity of 0.23 and an inclination of 13° with respect to the ecliptic.[2] The asteroid was first observed at Heidelberg Observatory in January 1925. The body's observation arc also begins at Heidelberg in August 1942, more than 11 years after its official discovery observation at Johannesburg.[1]

    Naming

    This minor planet was named for the former British colony and unrecognized state of Rhodesia (1965–1979) in southern Africa, what is now Zimbabwe. The official naming citation was mentioned in The Names of the Minor Planets by Paul Herget in 1955 (H 111).[13]

    Physical characteristics

    Rhodesia is an assumed C-type asteroid which agrees with its albedo and its location in the main belt.[10] It has a B–V color index of 0.740.[2][3]

    Rotation period

    In December 2017, a rotational lightcurve of Rhodesia was obtained from photometric observations by Tom Polakis at the Command Module Observatory (V02) in Tempe, Arizona. Lightcurve analysis gave a rotation period of 16.060±0.006 hours with a brightness variation of 0.27 magnitude (U=3-).[9] This result refines previous period determinations of 15.89 and 16.062 hours by Richard Binzel (1984) and Laurent Bernasconi (2005), respectively (U=2/2).[12][14]

    Diameter and albedo

    According to the surveys carried out by the Infrared Astronomical Satellite IRAS, the Japanese Akari satellite and the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Rhodesia measures between 46.43 and 52.276 kilometers in diameter and its surface has an albedo between 0.0548 and 0.0783.[5][6][7][8][11][15][16] The Collaborative Asteroid Lightcurve Link derives an albedo of 0.0666 and a diameter of 47.40 kilometers based on an absolute magnitude of 10.18.[10] In August 2015, an occultation by Rhodesia determined a cross-section of 48.0 × 48.0 kilometers (no fit).[3]

    References
    1. "1197 Rhodesia (1931 LD)". Minor Planet Center. Retrieved 31 July 2018.
    2. "JPL Small-Body Database Browser: 1197 Rhodesia (1931 LD)" (2018-05-24 last obs.). Jet Propulsion Laboratory. Retrieved 31 July 2018.
    3. "Asteroid 1197 Rhodesia". Small Bodies Data Ferret. Retrieved 31 July 2018.
    4. "Asteroid (1197) Rhodesia – Proper elements". AstDyS-2, Asteroids – Dynamic Site. Retrieved 25 May 2018.
    5. Tedesco, E. F.; Noah, P. V.; Noah, M.; Price, S. D. (October 2004). "IRAS Minor Planet Survey V6.0". NASA Planetary Data System – IRAS-A-FPA-3-RDR-IMPS-V6.0: IRAS-A-FPA-3-RDR-IMPS-V6.0. Bibcode:2004PDSS...12.....T. Retrieved 31 July 2018.
    6. Mainzer, A. K.; Bauer, J. M.; Cutri, R. M.; Grav, T.; Kramer, E. A.; Masiero, J. R.; et al. (June 2016). "NEOWISE Diameters and Albedos V1.0". NASA Planetary Data System: EAR-A-COMPIL-5-NEOWISEDIAM-V1.0. Bibcode:2016PDSS..247.....M. Retrieved 31 July 2018.
    7. Masiero, Joseph R.; Grav, T.; Mainzer, A. K.; Nugent, C. R.; Bauer, J. M.; Stevenson, R.; et al. (August 2014). "Main-belt Asteroids with WISE/NEOWISE: Near-infrared Albedos". The Astrophysical Journal. 791 (2): 11. arXiv:1406.6645. Bibcode:2014ApJ...791..121M. doi:10.1088/0004-637X/791/2/121. S2CID 119293330.
    8. 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. (online, AcuA catalog p. 153)
    9. Polakis, Tom (April 2018). "Lightcurve Analysis for Eleven Main-belt Asteroids". The Minor Planet Bulletin. 45 (2): 199–203. Bibcode:2018MPBu...45..199P. ISSN 1052-8091.
    10. "LCDB Data for (1197) Rhodesia". Asteroid Lightcurve Database (LCDB). Retrieved 31 July 2018.
    11. 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. S2CID 35447010. (catalog)
    12. Binzel, R. P. (October 1987). "A photoelectric survey of 130 asteroids". Icarus. 72 (1): 135–208. Bibcode:1987Icar...72..135B. doi:10.1016/0019-1035(87)90125-4. ISSN 0019-1035.
    13. Schmadel, Lutz D. (2007). "(1197) Rhodesia". Dictionary of Minor Planet Names. Springer Berlin Heidelberg. p. 100. doi:10.1007/978-3-540-29925-7_1198. ISBN 978-3-540-00238-3.
    14. Behrend, Raoul. "Asteroids and comets rotation curves – (1197) Rhodesia". Geneva Observatory. Retrieved 31 July 2018.
    15. 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. S2CID 9341381.
    16. 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. S2CID 46350317.

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