Discovered by C. Jackson Discovery date 30 April 1935 Alternative names 1935 HE | Discovery site Johannesburg Obs. MPC designation 1355 Magoeba | |
Named after Magoeba
(South African chief) | ||
1355 Magoeba, provisional designation 1935 HE, is a Hungaria asteroid and a suspected binary from the innermost regions of the asteroid belt, approximately 5 kilometers in diameter. It was discovered on 30 April 1935, by English-born, South African astronomer Cyril Jackson at Johannesburg Observatory in South Africa. It is named for Magoeba, a tribal chief in the South African Transvaal Province.
Description
Magoeba is a member of the Hungaria family, which forms the innermost dense concentration of asteroids in the Solar System. It orbits the Sun at a distance of 1.8–1.9 AU once every 2 years and 6 months (922 days). Its orbit has an eccentricity of 0.04 and an inclination of 23° with respect to the ecliptic. The first precovery was taken at Nice Observatory just 3 day prior to its official discovery. The body's observation arc begins at Johannesburg the night after its discovery observation.
Between 2006 and 2014, several rotational light-curves of Magoeba were obtained by American astronomer Brian Warner at the CS3–Palmer Divide Observatory (see video in § External links). Light-curve analysis of the photometric observations taken during the asteroid's 2014-apparition gave a rotation period of 2.971 hours with a brightness variation of 0.09 magnitude (U=3). Previously derived periods varied strongly (5.99 and 31.65 hours) with alternative period solutions (U=2-/2/2). It is now suspected that this discrepancy might be caused by the presence of an asteroid moon that orbits Magoeba with a period of 15.05 hours.
According to the survey carried out by NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Magoeba measures 4.276 and 4.828 kilometers in diameter, and its surface has an albedo of 0.582 and 0.466, respectively, while a polarimetric study of Hungaria asteroids found a lower albedo of 0.267. The Collaborative Asteroid Lightcurve Link assumes an albedo of 0.30 – a compromise value between 0.4 and 0.2, corresponding to the Hungaria asteroids both as family and orbital group – and calculates a diameter of 5.96 kilometers, based on an absolute magnitude of 13.05.
In the Tholen taxonomy, Magoeba is a X-type asteroid, which can be further divided into the bright E, the metallic M and the carbonaceous P classes, with similar spectra but very different inferred mineralogies. It has both been classified as an E-type asteroid by the WISE/NEOWISE mission, and as a M-type asteroid by a dedicated spectroscopic survey at the Argentinian Lencito Complex, respectively.
The minor planet was named for Magoeba, a native chief of the North Transvaal in South Africa. Naming citation was published before November 1977 (M.P.C. 908).