| Discovery[1] | |
|---|---|
| Discovered by | Y. Väisälä |
| Discovery site | Turku Obs. |
| Discovery date | 26 January 1938 |
| Designations | |
| (1447) Utra | |
Named after | Utra(Finnish town)[2] |
| 1938 BB · 1936 SB 1951 KO · A918 FA | |
| main-belt · (middle)[3] | |
| Orbital characteristics[1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 98.67 yr (36,038 days) |
| Aphelion | 2.6404AU |
| Perihelion | 2.4299 AU |
| 2.5352 AU | |
| Eccentricity | 0.0415 |
| 4.04yr (1,474 days) | |
| 285.64° | |
| 0° 14m 39.12s / day | |
| Inclination | 4.7865° |
| 35.528° | |
| 64.085° | |
| Physical characteristics | |
| Dimensions | 11.83±0.86 km[4] 11.834±0.122 km[5] 12.634±0.103 km[6] 13.26±0.53 km[7] 13.58 km(calculated)[3] |
| 257±30h[a] | |
| 0.20(assumed)[3] 0.303±0.038[7] 0.3381±0.0591[6] 0.381±0.058[4] | |
| S[3] | |
| 11.30[4][6][7] · 11.60±0.44[8] · 11.7[1][3] | |
1447 Utra, provisional designation1938 BB, is a stonyasteroid,slow rotator and suspected tumbler from the central region of theasteroid belt, approximately 12 kilometers in diameter. It was discovered on 26 January 1938, by Finnish astronomerYrjö Väisälä atTurku Observatory in Southwest Finland.[9] The asteroid was named for the Finnish town ofUtra (now a part ofJoensuu).[2]
Utra is aS-type asteroid. It orbits the Sun in thecentral main-belt at a distance of 2.4–2.6 AU once every 4.04 years (1,474 days). Its orbit has aneccentricity of 0.04 and aninclination of 5° with respect to theecliptic.[1]Utra was first identified asA918 FA atHeidelberg Observatory in 1918. The body'sobservation arc begins with its official discovery observation at Turku in 1938.[9]
In March 2011, a rotationallightcurve ofUtra was obtained from photometric observations by astronomer Luis E. Martinez. Lightcurve analysis gave a longrotation period of 257 hours with a brightness variation of 0.63magnitude (U=2). Thisslow rotator is also a suspected tumbler (T0).[a]
According to the surveys carried out by the JapaneseAkari satellite and NASA'sWide-field Infrared Survey Explorer with its subsequentNEOWISE mission,Utra measures between 11.83 and 13.26 kilometers in diameter, and its surface has analbedo between 0.303 and 0.381.[4][5][6][7] TheCollaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20 and calculates a diameter of 13.58 kilometers with anabsolute magnitude of 11.7.[3]
Thisminor planet was named for Utra, a northeastern Finnish town and birthplace of the discoverer.[2] The officialnaming citation was published by theMinor Planet Center on 30 January 1964 (M.P.C. 2277).[10]
