| 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 | 1.9363AU |
| Perihelion | 1.7707 AU |
| 1.8535 AU | |
| Eccentricity | 0.0447 |
| 2.52yr (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±0.0003h[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 designation1935 HE, is a Hungariaasteroid and a suspectedcontact-binary from the innermost regions of theasteroid belt, approximately 5 kilometers in diameter. It was discovered on 30 April 1935, by English-born, South African astronomerCyril Jackson at theJohannesburg Observatory in South Africa.[3] The asteroid is named forMagoeba, a tribal chief in the South AfricanTransvaal Province.[2]
Magoeba is a member of theHungaria family, which forms the innermost dense concentration of asteroids in theSolar System. It orbits the Sun in theinner main-belt at a distance of 1.8–1.9 AU once every 2 years and 6 months (922 days). Its orbit has aneccentricity of 0.04 and aninclination of 23° with respect to theecliptic.[1] The firstprecovery was taken atNice Observatory just 3 day prior to its official discovery. The body'sobservation arc begins at Johannesburg the night after its discovery observation.[3]
Between 2006 and 2014, several rotationallightcurves ofMagoeba were obtained by American astronomerBrian Warner at the CS3–Palmer Divide Station (U82) in California. Lightcurve analysis of the photometric observations taken during the asteroid's 2014-apparition gave arotation period of 2.971 hours with a brightness variation of 0.09magnitude (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 anasteroid moon that orbitsMagoeba with a period of 15.05 hours.[7]
According to the survey carried out by NASA'sWide-field Infrared Survey Explorer with its subsequentNEOWISE mission,Magoeba measures 4.276 and 4.828 kilometers in diameter, and its surface has analbedo of 0.582 and 0.466, respectively,[5][6] while apolarimetric 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 anabsolute magnitude of 13.05.[4]
In theTholen taxonomy,Magoeba is anX-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 inferredmineralogies.[13] It has both been classified as anE-type asteroid by the WISE/NEOWISE mission, and as aM-type asteroid by a dedicated spectroscopic survey at the ArgentinianLencito Complex, respectively.[6][13]
Thisminor planet was named for Magoeba, anative chief of theNorth Transvaal in South Africa.[2] The officialnaming citation was published by theMinor Planet Center in April 1953 (M.P.C. 908).[15]
