| Discovery[1] | |
|---|---|
| Discovered by | C. Jackson |
| Discovery site | Johannesburg Obs. |
| Discovery date | 23 July 1932 |
| Designations | |
| (1246) Chaka | |
Named after | Shaka(King of the Zulus)[2] |
| 1932 OA | |
| main-belt[1][3] · (middle) background[4][5] | |
| Orbital characteristics[3] | |
| Epoch 27 April 2019 (JD 2458600.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 86.29yr (31,519 d) |
| Aphelion | 3.4329AU |
| Perihelion | 1.8068 AU |
| 2.6198 AU | |
| Eccentricity | 0.3103 |
| 4.24 yr (1,549 d) | |
| 128.91° | |
| 0° 13m 56.64s / day | |
| Inclination | 16.004° |
| 290.52° | |
| 54.847° | |
| Physical characteristics | |
| 17.634±0.498 km[6][7] 17.73±3.89 km[8] 18.11±0.9 km[9] 19.596±0.035 km[10] 20.84±1.39 km[11] | |
| 25.462±0.001 h[a] | |
| 0.195[11] 0.2045[10] 0.2351[9] 0.26[8] 0.310[6] | |
| A(S3OS2-TH)[12] Sl(S3OS2-BB)[12] | |
| 10.8[8][11] 10.9[1][3][6][9][10] | |
1246 Chaka, provisional designation1932 OA, is a backgroundasteroid from the central regions of theasteroid belt, approximately 18 kilometers (11 miles) in diameter. It was discovered on 23 July 1932, by South African astronomerCyril Jackson at theUnion Observatory in Johannesburg.[1] The uncommonA/Sl-type asteroid has a longer than averagerotation period of 25.5 hours.[13] It was named for the Zulu KingShaka.[2]
Chaka is a non-family asteroid from the main belt'sbackground population.[4][5] It orbits the Sun in thecentral asteroid belt at a distance of 1.8–3.4 AU once every 4 years and 3 months (1,549 days;semi-major axis of 2.62 AU). Its orbit has aneccentricity of 0.31 and aninclination of 16° with respect to theecliptic.[3] The body'sobservation arc begins with its first observation at Johannesburg on 4 July 1932, three weeks prior to its official discovery observation.[1]
Thisminor planet was named afterShaka (c.1787–1828), also Chaka or Tchaka, founder and one of the most influential monarchs of theZulu Kingdom. The officialnaming citation was mentioned inThe Names of the Minor Planets byPaul Herget in 1955 (H 115).[2]
Chaka'sspectral type has been determined during theSmall Solar System Objects Spectroscopic Survey (S3OS2). In the Tholen-like taxonomic variant of the survey, the asteroid is a rareA-type, while in the SMASS-like variant it is a Sl-subtype, that transitions between the commonS- and uncommonL-type asteroids.[4][12]
In October 2013, a rotationallightcurve ofChaka was obtained fromphotometric observations by Joe Garlitz at his Elgin Observatory. Lightcurve analysis gave a well-definedrotation period of25.462±0.001 hours with a brightness amplitude of 0.18magnitude (U=3).[a] Other period determinations were made by European astronomers (20 h; Δ0.2) atOHP andLa Silla in October 1996 (U=2),[14] and by Andrea Ferrero (25.44 h; Δ0.25) at the Italian Bigmuskie Observatory (B88) in November 2013 (U=2).[15]
According to the surveys carried out by the Infrared Astronomical SatelliteIRAS and theNEOWISE mission of NASA'sWide-field Infrared Survey Explorer,Chaka measures between 17.63 and 20.84 kilometers in diameter and its surface has analbedo between 0.195 and 0.310.[6][7][8][9][10][11] TheCollaborative Asteroid Lightcurve Link adopts the results obtained by IRAS, that is, an albedo of 0.2351 and a diameter of 18.11 kilometers based on anabsolute magnitude of 10.9.[13]
