| Discovery[1] | |
|---|---|
| Discovered by | C. Jackson |
| Discovery site | Johannesburg Obs. |
| Discovery date | 13 May 1931 |
| Designations | |
| (1194) Aletta | |
Named after | Aletta Jackson (discoverer's wife)[2] |
| 1931 JG · 1946 KC 1962 SB | |
| main-belt · (outer)[3] | |
| Orbital characteristics[1] | |
| Epoch 16 February 2017 (JD 2457800.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 85.07 yr (31,072 days) |
| Aphelion | 3.1812AU |
| Perihelion | 2.6452 AU |
| 2.9132 AU | |
| Eccentricity | 0.0920 |
| 4.97yr (1,816 days) | |
| 138.73° | |
| 0° 11m 53.52s / day | |
| Inclination | 10.870° |
| 291.32° | |
| 243.18° | |
| Physical characteristics | |
| Dimensions | 41.358±0.191 km[4] 42.67±0.77 km[5] 46.371±1.188 km[6] 55.22±20.92 km[7] 55.23 km(derived)[3] 55.39±1.4 km[8] |
| 19.7±0.1h[9] 20.39±0.01 h[10] 20.3903±0.2170 h[11] | |
| 0.03±0.03[7] 0.0333(derived)[3] 0.0375±0.0065[6] 0.0479±0.003[8] 0.085±0.004[5] 0.087±0.011[4] | |
| C[3] | |
| 10.2[5][6][8] · 10.5[12] · 10.6[1][3][7] · 10.644±0.001(R)[11] | |
1194 Aletta, provisional designation1931 JG, is a carbonaceousasteroid from the outer region of theasteroid belt, approximately 55 kilometers in diameter. It was discovered on 13 May 1931, by South African astronomerCyril Jackson atJohannesburg Observatory in South Africa.[13] It was later named after the discoverer's wife Aletta Jackson.[2]
Aletta is a darkC-type asteroid and orbits the Sun at a distance of 2.6–3.2 AU once every 4 years and 12 months (1,816 days). Its orbit has aneccentricity of 0.09 and aninclination of 11° with respect to theecliptic.[1] The body'sobservation arc begins at Johannesburg, one week after its official discovery observation. Noprecoveries were taken and no prior identifications were made.[13]
According to the surveys carried out by the Infrared Astronomical SatelliteIRAS, the JapaneseAkari satellite, and NASA'sWide-field Infrared Survey Explorer with its subsequentNEOWISE mission,Aletta measures between 41.358 and 55.39 kilometers in diameter, and its surface has analbedo between 0.03 and 0.87.[4][5][6][7][8] TheCollaborative Asteroid Lightcurve Link derives an albedo of 0.0333 and a diameter of 55.23 kilometers based on anabsolute magnitude of 10.6.[3]
In November 2007, American astronomer James W. Brinsfield obtained the first everlightcurve ofAletta with period of 19.7 hours and a brightness variation of 0.32magnitude at Via Capote Observatory (U=2).[9] Two morelightcurves were obtained by Australian astronomer Julian Oey at Leura/Kingsgrove Observatory in March 2010, and by the Survey conducted at thePalomar Transient Factory, California, in October 2012. Lightcurve analysis gave a concurringrotation period of 20.39 and 20.3903 hours with an amplitude of 0.28 and 0.27 magnitude, respectively (U=2+/2).[10][11]
The discoverer named thisminor planet for his wife, Aletta Jackson (née Maria Aletta Lessing).[2] Naming citation was first mentioned inThe Names of the Minor Planets byPaul Herget in 1955 (H 111).[2]
