| Discovery[1] | |
|---|---|
| Discovered by | E. Bowell |
| Discovery site | Anderson Mesa Stn. |
| Discovery date | 15 September 1982 |
| Designations | |
| (2815) Soma | |
| Pronunciation | /ˈsoʊmə/[2] |
Named after | Soma cube (mechanical puzzle)[3] |
| 1982 RL · 1955 MH 1970 AC · 1974 DL 1979 XB1 | |
| main-belt · Flora[4] | |
| Orbital characteristics[1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 61.77 yr (22,562 days) |
| Aphelion | 2.6107AU |
| Perihelion | 1.8552 AU |
| 2.2329 AU | |
| Eccentricity | 0.1692 |
| 3.34yr (1,219 days) | |
| 168.50° | |
| 0° 17m 43.44s / day | |
| Inclination | 5.7042° |
| 119.87° | |
| 237.53° | |
| Knownsatellites | 1[4][5][6] (Ds/Dp:0.25±0.02) (orbital period: 17.915 h) |
| Physical characteristics | |
| Dimensions | 6.641±0.105 km[7] 7.067 km[8] 7.07 km(taken)[4] 7.158±0.088 km[9] |
| 2.7327±0.0008h[a] 2.73325±0.00007 h[5] | |
| 0.2273[8] 0.3207±0.0411[9] 0.365±0.083[7] | |
| S[4] | |
| 12.49±0.06(R)[a] · 12.53±0.02(R)[5] · 12.6[9] · 12.7[1] · 12.92±0.16[10] · 12.98±0.078[4][8] | |
2815 Soma, provisional designation1982 RL, is abinary Florianasteroid from the inner regions of theasteroid belt, approximately 7 kilometers in diameter. It was discovered on 15 September 1982, by American astronomerEdward Bowell at Lowell'sAnderson Mesa Station in Flagstaff, Arizona, in the United States .[11] It is named for the mechanical puzzleSoma cube.[3]
Soma is a member of theFlora family, a large family ofstony asteroids. It orbits the Sun in theinner main-belt at a distance of 1.9–2.6 AU once every 3 years and 4 months (1,219 days). Its orbit has aneccentricity of 0.17 and aninclination of 6° with respect to theecliptic.[1] It was first identified as1955 MH atGoethe Link Observatory in 1955. The body'sobservation arc begins with1970 AC atCrimea-Nauchnij, 12 years prior to its official discovery at Anderson Mesa.[11]
According to the survey carried out by NASA'sWide-field Infrared Survey Explorer (WISE) with its subsequentNEOWISE mission,Soma measures 6.641 and 7.158 kilometers in diameter and its surface has analbedo of 0.365 and 0.3207, respectively.[7][9] TheCollaborative Asteroid Lightcurve Link adopts Peter Pravec's revised WISE-data, that is, an albedo of 0.2273 and a diameter of 7.067 kilometers with anabsolute magnitude of 12.98.[4][8]
In November 2009, a rotationallightcurve ofSoma was obtained from photometric observations by astronomersPetr Pravec,Donald Pray andPeter Kušnirák at Carbuncle Hill Observatory, Rhode Island, andOndřejov Observatory, in the Czech Republic, respectively. Lightcurve analysis gave arotation period of 2.7327 hours with a brightness variation of 0.08magnitude, indicating that the body has a nearly spheroidal shape (U=3-).[a] The body's spin rate is within the 2.2-to-20 hours range found for most asteroids, about half an hour longer than the so-calledfast rotators.
In March 2011, photometric observations revealed thatSoma is a synchronousbinary asteroid with aminor-planet moon orbiting it every 17.915 hours. The system has a secondary-to-primary mean-diameter ratio of 0.25, which means that satellite's diameter measures approximately 25% of that ofSoma (the primary), and translate into a diameter of 1.75 kilometers.[5] The observations also gave a refined rotation period forSoma of 2.73325 hours and an amplitude of 0.07 magnitude (U=n.a.). The system has an absolute magnitude of 12.53, and aphase slope parameter (G) of 0.27.[5]
Thisminor planet was named for theSoma cube, following a proposal by Belgian astronomerJean Meeus(also see2213 Meeus). The Soma cube a dissection puzzle with seven pieces, invented by the Danish mathematicianPiet Hein and popularized by American writerMartin Gardner(also see2587 Gardner).[3] The approved naming citation was published by theMinor Planet Center on 10 September 1984 (M.P.C. 9080).[12]
