| Discovery[1] | |
|---|---|
| Discovered by | Y. Väisälä |
| Discovery site | Turku Obs. |
| Discovery date | 19 January 1939 |
| Designations | |
| (1646) Rosseland | |
Named after | Svein Rosseland (astrophysicist)[2] |
| 1939 BG · 1937 QH 1948 QR · 1955 NB 1977 FK · 1980 ME | |
| main-belt · (inner)[3] | |
| Orbital characteristics[1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 79.69 yr (29,105 days) |
| Aphelion | 2.6435AU |
| Perihelion | 2.0771 AU |
| 2.3603 AU | |
| Eccentricity | 0.1200 |
| 3.63yr (1,324 days) | |
| 320.86° | |
| 0° 16m 18.48s / day | |
| Inclination | 8.3787° |
| 119.98° | |
| 279.82° | |
| Physical characteristics | |
| Dimensions | 11.48±3.28 km[4] 11.50±2.88 km[5] 12.130±0.007 km[6] 12.801±0.231 km[7] 12.85 km(calculated)[3] 13.49±0.27 km[8] |
| 68.9h[9] 69.2 h[10] | |
| 0.18±0.10[5] 0.186±0.008[8] 0.19±0.07[4] 0.20(assumed)[3] 0.202±0.030[7] 0.2253±0.0341[6] | |
| S[3] | |
| 11.82[1][3][4][6][7][8] · 11.97±0.11[11] · 12.06[5] | |
1646 Rosseland, provisional designation1939 BG, is a stonyasteroid from the inner regions of theasteroid belt, approximately 12 kilometers in diameter. It was discovered on 19 January 1939, by Finnish astronomerYrjö Väisälä atTurku Observatory in Southwest Finland.[12] It was later named after Norwegian astrophysicistSvein Rosseland.[2]
TheS-type asteroid orbits the Sun in theinner main-belt at a distance of 2.1–2.6 AU once every 3 years and 8 months (1,324 days). Its orbit has aneccentricity of 0.12 and aninclination of 8° with respect to theecliptic.[1]Rosseland was first observed atJohannesburg Observatory as1937 QH, extending the body'sobservation arc by 2 years prior to its official discovery observation in 1939.[12]
American astronomerRichard Binzel obtained the first rotationallightcurve ofRosseland in the early 1980s. It gave arotation period of 69.2 hours with a brightness variation of 0.13magnitude (U=2).[10] During a survey of presumedslow rotators, photometric observations by Brazilian Cláudia Angeli and colleges gave a period of 69.2 hours and an amplitude of 0.45 magnitude (U=1).[9]
According to the surveys carried out by the JapaneseAkari satellite and NASA'sWide-field Infrared Survey Explorer with its subsequentNEOWISE mission,Rosseland measures between 11.48 and 13.49 kilometers in diameter and its surface has analbedo between 0.18 and 0.2253.[4][5][6][7][8] TheCollaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20 and calculates a diameter of 12.85 kilometers with anabsolute magnitude of 11.82.[3]
Thisminor planet was named in honor of renowned Norwegian astrophysicistSvein Rosseland (1894–1985), founder and first director of theInstitute for TheoreticalAstrophysics in Oslo. His work on the theory of stellar interiors included studies of stellar rotation and stability and the derivation of theRosseland mean opacity.[2] The lunar craterRosseland is also named after him. The officialnaming citation was published by theMinor Planet Center on 20 February 1976 (M.P.C. 3932).[13]
