| Discovery[1] | |
|---|---|
| Discovered by | C. Jackson |
| Discovery site | Johannesburg Obs. |
| Discovery date | 25 May 1936 |
| Designations | |
| (1393) Sofala | |
Named after | Sofala (Province in Mozambique)[2] |
| 1936 KD · 1928 FB 1951 GL · 1956 TE 1958 CA · 1971 SJ 1975 UB | |
| main-belt · (inner) Vestian[3] · background[4] | |
| Orbital characteristics[1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 89.54 yr (32,703 days) |
| Aphelion | 2.6997AU |
| Perihelion | 2.1685 AU |
| 2.4341 AU | |
| Eccentricity | 0.1091 |
| 3.80yr (1,387 days) | |
| 146.78° | |
| 0° 15m 34.2s / day | |
| Inclination | 5.8476° |
| 56.701° | |
| 183.46° | |
| Physical characteristics | |
| Dimensions | 11.214±0.495 km[5] 11.30 km(calculated)[3] |
| 7.8h(poor)[6] 16.5931±0.0005 h[7] 108.259±0.7031 h[8] | |
| 0.20(assumed)[3] 0.223±0.046[5] | |
| S(assumed)[3] | |
| 11.835±0.002(R)[8] · 12.00[5] · 12.1[1][3] · 12.42±0.78[9] | |
1393 Sofala, provisional designation1936 KD, is a Vestianasteroid from the inner regions of theasteroid belt, approximately 11 kilometers in diameter. It was discovered on 25 May 1936, by South African astronomerCyril Jackson at theUnion Observatory in Johannesburg.[10] The asteroid was named after the province ofSofala in Mozambique.[2]
Sofala is a member of theVesta family (401),[3] the second-largest asteroid family of the main-belt by number of members. However, it is also considered to be a non-family asteroid of the main belt'sbackground population when applying theHierarchical Clustering Method to itsproper orbital elements.[4] It orbits the Sun in theinner asteroid belt at a distance of 2.2–2.7 AU once every 3 years and 10 months (1,387 days). Its orbit has aneccentricity of 0.11 and aninclination of 6° with respect to theecliptic.[1]
The asteroid was first identified as1928 FB atHeidelberg Observatory in March 1928. The body'sobservation arc begins with its official discovery observation at Johannesburg in 1936.[10]
Sofala is an assumed stonyS-type asteroid.[3]
The asteroid has an ambiguouslightcurve. While a lightcurve, obtained at thePalomar Transient Factory in September 2013, gave arotation period of 108.259 hours with a brightness amplitude of 0.48magnitude (U=2),[8] another lightcurve modeled from combined dense and sparse photometry gave a sidereal period of 16.5931 hours.(U=2).[7] If the first result were correct,Sofala would be one of few hundred knownslow rotators with a period above 100 hours. The Lightcurve Data Base, however, adopts the shorter period from the modeled lightcurve.[3] A third lightcurve with a period of 7.8 hours byRené Roy from 2008 has received a poor rating.[6]
According to the survey carried out by theNEOWISE mission of NASA'sWide-field Infrared Survey Explorer,Sofala measures between 11.21 kilometers in diameter and its surface has analbedo of 0.223.[5]
TheCollaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20 and calculates a diameter of 11.30 kilometers based on anabsolute magnitude of 12.1.[3]
Thisminor planet was named afterSofala Province in central-eastern Mozambique. It is the country's largest province.[2] Its capital city isBeira after which the Mars-crosser1474 Beira, another discovery by Cyril Jackson, is named. The officialnaming citation was published by theMinor Planet Center in April 1953 (M.P.C. 909).[11]
