Discovery [1] | |
---|---|
Discovered by | C. Jackson |
Discovery site | Johannesburg Obs. |
Discovery date | 30 April 1935 |
Designations | |
(1355) Magoeba | |
Named after | Magoeba (South African chief) [2] |
1935 HE | |
main-belt · Hungaria [3] [4] | |
Orbital characteristics [1] | |
Epoch 4 September 2017 ( JD 2458000.5) | |
Uncertainty parameter 0 | |
Observation arc | 81.71 yr (29,843 days) |
Aphelion | 1.9363 AU |
Perihelion | 1.7707 AU |
1.8535 AU | |
Eccentricity | 0.0447 |
2.52 yr (922 days) | |
245.86 ° | |
0° 23m 26.16s / day | |
Inclination | 22.827° |
225.25° | |
340.40° | |
Physical characteristics | |
Dimensions | 4.276±0.170 km
[5] 4.828±0.094 km [6] 5.96 km (calculated) [4] |
2.9712±0.0003
h
[7] 2.972±0.002 h [8] 2.975±0.002 h [8] 5.946±0.005 h [9] 5.99±0.05 h [10] [a] 31.65±0.05 h [9] 32.9±0.1 h [11] | |
0.267±0.095
[12] 0.3 (assumed) [4] 0.4663±0.0824 [6] 0.582±0.049 [5] | |
Tholen =
X
[1] ·
M
[13] ·
E
[6] ·
X
[4] B–V = 0.713 [1] U–B = 0.255 [1] | |
13.02±0.22 [14] · 13.05 [1] [4] [6] | |
1355 Magoeba, provisional designation 1935 HE, is a Hungaria asteroid and a suspected contact-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 the Johannesburg Observatory in South Africa. [3] The asteroid is named for Magoeba, a tribal chief in the South African Transvaal Province. [2]
Magoeba is a member of the Hungaria family, which forms the innermost dense concentration of asteroids in the Solar System. It orbits the Sun in the inner main-belt 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. [1] 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. [3]
Between 2006 and 2014, several rotational lightcurves of Magoeba were obtained by American astronomer Brian Warner at the CS3–Palmer Divide Station ( U82) in California. Lightcurve 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). [7] [b]
Previously derived periods varied strongly (5.99 and 31.65 hours) with alternative period solutions ( U=2-/2/2). [9] [10] [11] [a] The Observation were taken at the Palmer Divide Observatory ( 716) in Colorado (see video in § External links). 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. [7]
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, [5] [6] while a polarimetric study of Hungaria asteroids found a lower albedo of 0.267. [12] 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 with an absolute magnitude of 13.05. [4]
In the Tholen taxonomy, Magoeba is an 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. [13] 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. [6] [13]
This minor planet was named for Magoeba, a native chief of the North Transvaal in South Africa. [2] The official naming citation was published by the Minor Planet Center in April 1953 ( M.P.C. 908). [15]