| Discovery[1] | |
|---|---|
| Discovered by | C. Kowal |
| Discovery site | Palomar Obs. |
| Discovery date | 17 October 1974 |
| Designations | |
| (1939) Loretta | |
Named after | Loretta Kowal (daughter of discoverer)[2] |
| 1974 UC · 1934 JE 1934 LQ · 1939 EH 1939 GP · 1950 DT 1950 ES · 1951 MF 1955 CA · 1969 TE5 1975 TZ5 · 1975 XW | |
| main-belt · Themistian[3] | |
| Orbital characteristics[1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 67.21 yr (24,547 days) |
| Aphelion | 3.5154AU |
| Perihelion | 2.7291 AU |
| 3.1222 AU | |
| Eccentricity | 0.1259 |
| 5.52yr (2,015 days) | |
| 24.968° | |
| 0° 10m 43.32s / day | |
| Inclination | 0.9058° |
| 40.473° | |
| 189.36° | |
| Physical characteristics | |
| Dimensions | 26.34±0.46 km[4] 29.08±0.51 km[5] 29.83 km(derived)[3] 30.243±0.335 km[6] 30.365±0.351[7] |
| 25h[8] | |
| 0.0721(derived)[3] 0.092±0.013[7] 0.0927±0.0089[6] 0.101±0.020[4] 0.103±0.004[5] | |
| C[3] | |
| 10.8[5][6] · 11.0[4] · 11.1[1][3] | |
1939 Loretta, provisional designation1974 UC, is a carbonaceous Themistianasteroid from the outer region of theasteroid belt, approximately 30 kilometers in diameter. It was discovered on 17 October 1974, by American astronomerCharles Kowal atPalomar Observatory in California, who named it after his daughter, Loretta Kowal.[2][9] The discovery of the asteroid took place during Kowal's follow-up observations ofJupiter's moonLeda, which he had discovered one month prior.[10]
Loretta is a member of theThemis family, a dynamical family of main-belt asteroids with nearly coplanarecliptical orbits.[3] It orbits the Sun in theouter main-belt at a distance of 2.7–3.5 AU once every 5 years and 6 months (2,015 days). Its orbit has aneccentricity of 0.13 and aninclination of 1° with respect to the ecliptic.[1]
First identified as1934 JE at the South AfricanJohannesburg Observatory,Loretta's first used observation was made at the FinnishTurku Observatory in 1939, extending the body'sobservation arc by 35 years prior to its discovery.[9]
Loretta has been characterized as a carbonaceousC-type asteroid.[1]
According to the surveys carried out by the JapaneseAkari satellite and NASA'sWide-field Infrared Survey Explorer with its subsequentNEOWISE mission,Loretta measures between 26.3 and 30.4 kilometers in diameter, and its surface has analbedo between 0.092 and 0.101.[4][5][6][7] TheCollaborative Asteroid Lightcurve Link derives an albedo of 0.072 and a diameter of 29.8 kilometers with anabsolute magnitude of 11.1.[3]
A fragmentary rotationallightcurve ofLoretta was obtained from photometric observations made by French amateur astronomerPierre Antonini in March 2011. It gave an approximaterotation period of 25 hours with a brightness variation of 0.12 magnitude (U=1).[8]
Thisminor planet was named by the discoverer after his daughter, Loretta Kowal.[2] The officialnaming citation was published by theMinor Planet Center on 1 June 1975 (M.P.C. 3828).[11]
