1193 Africa

1193 Africa, provisional designation 1931 HB, is a stony Eunomian asteroid from the central region of the asteroid belt, approximately 12 kilometers in diameter. It was discovered by South African astronomer Cyril Jackson at Johannesburg Observatory on 24 April 1931.[6] The asteroid was named for the African continent.[2]

1193 Africa
Discovery [1]
Discovered byC. Jackson
Discovery siteJohannesburg Obs.
Discovery date24 April 1931
Designations
(1193) Africa
Named after
Africa (continent)[2]
1931 HB
main-belt [1] · (middle)
Eunomia [3][4]
Orbital characteristics [1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc86.20 yr (31,484 days)
Aphelion2.9728 AU
Perihelion2.3198 AU
2.6463 AU
Eccentricity0.1234
4.30 yr (1,572 days)
9.0113°
0° 13m 44.4s / day
Inclination14.141°
49.538°
183.92°
Physical characteristics
Dimensions12.220±0.102 km[5]
13 km (est. at 0.21)
0.21 (derived)
0.247±0.038[5]
S (derived)
11.8[1]

    Orbit and classification

    Africa is a member of the Eunomia family (502), a large group of typically S-type asteroids and the most prominent family in the intermediate main-belt.[3][4] It orbits the Sun at a distance of 2.3–3.0 AU once every 4 years and 4 months (1,572 days). Its orbit has an eccentricity of 0.12 and an inclination of 14° with respect to the ecliptic.[1] The body's observation arc begins with its official discovery observation at Johannesburg.[6]

    Physical characteristics

    Diameter and albedo

    According to the survey carried out by NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Africa measures 12.22 kilometers in diameter and its surface has an albedo of 0.247.[5] Based on a generic magnitude-to-diameter conversion, Africa measures 13 kilometers in diameter, using an absolute magnitude of 11.8 and a standard albedo for Eunomian asteroids of 0.21, derived from 15 Eunomia, the family's largest member and namesake.[7]

    Photometry

    As of 2017, no rotational lightcurve of Africa has been obtained from photometric observations. The body's rotation period, poles and shape still remain unknown.[1][8]

    Naming

    This minor planet was named for Africa, the large continent on which Johannesburg is located.[2] The official naming citation was also mentioned in Paul Herget's The Names of the Minor Planets in 1955 (H 111).[2]

    References
    1. "JPL Small-Body Database Browser: 1193 Africa (1931 HB)" (2017-07-05 last obs.). Jet Propulsion Laboratory. Retrieved 15 August 2017.
    2. Schmadel, Lutz D. (2007). "(1193) Africa". Dictionary of Minor Planet Names – (1193) Africa. Springer Berlin Heidelberg. p. 100. doi:10.1007/978-3-540-29925-7_1194. ISBN 978-3-540-00238-3.
    3. 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.
    4. "Asteroid 1193 Africa – Nesvorny HCM Asteroid Families V3.0". Small Bodies Data Ferret. Retrieved 26 October 2019.
    5. 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 15 August 2017.
    6. "1193 Africa (1931 HB)". Minor Planet Center. Retrieved 15 August 2017.
    7. "Asteroid Size Estimator". CNEOS/JPL. Retrieved 2 August 2017.
    8. "LCDB Data for (1193) Africa". Asteroid Lightcurve Database (LCDB). Retrieved 15 August 2017.

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