_Prisma.png) Modelled shape ofPrisma from itslightcurve | |
| Discovery[1] | |
|---|---|
| Discovered by | A. Schwassmann |
| Discovery site | Bergedorf Obs. |
| Discovery date | 17 March 1931 |
| Designations | |
| (1192) Prisma | |
Named after | Bergedorf Spectral Catalogue (astronomical catalog)[2] |
| 1931 FE | |
| main-belt · (inner) Phocaea[3][4] | |
| Orbital characteristics[1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 85.77 yr (31,328 days) |
| Aphelion | 2.9762AU |
| Perihelion | 1.7561 AU |
| 2.3661 AU | |
| Eccentricity | 0.2578 |
| 3.64yr (1,329 days) | |
| 297.62° | |
| 0° 16m 14.88s / day | |
| Inclination | 23.902° |
| 1.3517° | |
| 131.44° | |
| Physical characteristics | |
| Dimensions | 7.22 km(calculated)[3] 7.377±0.193 km[5] 9.27±0.25 km[6] |
| 6.546±0.0170 h[7] 6.558h[8] 6.55836±0.00005 h[9][10] | |
| 0.144±0.009[6] 0.220±0.022[5] 0.23(assumed)[3] | |
| S[3] | |
| 12.497±0.008(R)[7] · 12.87±0.47[11] · 12.92[1][3][5][6] | |
1192 Prisma, provisional designation1931 FE, is an elongatedPhocaea asteroid from the inner regions of theasteroid belt, approximately 7 kilometers in diameter. It was discovered by German astronomerFriedrich Schwassmann at theBergedorf Observatory in Hamburg on 17 March 1931.[12] The asteroid was named after theBergedorf Spectral Catalogue, anastronomical catalog.[2]
Prisma is a member of thePhocaea family (701), a prominent family ofS-type asteroids with their largest members being25 Phocaea and587 Hypsipyle. There are manyMars-crossers among this family of relatively eccentricinner main-belt asteroids .[13]
The asteroid orbits the Sun at a distance of 1.8–3.0 AU once every 3 years and 8 months (1,329 days). Its orbit has aneccentricity of 0.26 and aninclination of 24° with respect to theecliptic.[1] The body'sobservation arc begins at Bergedorf, one week after its official discovery observation.[12]
Photometric observations ofPrisma gave a well defined rotationallightcurve with aperiod between 6.546 and 6.558 hours and a high brightness variation of 0.85–1.16magnitude, which strongly indicates that the body has an elongated, non-spheroidal shape (U=3/3).[7][8]
A modeled lightcurve based on optical data from a large collaboration network also found aspin axis of (133.0°, −78.0°) inecliptic coordinates (λ, β) (Q=n.a.).[9][10]
According to the surveys carried out by the JapaneseAkari satellite, and NASA'sWide-field Infrared Survey Explorer with its subsequentNEOWISE mission,Prisma measures between 7.38 and 9.27 kilometers in diameter and its surface has analbedo between 0.144 and 0.220.[5][6] TheCollaborative Asteroid Lightcurve Link assumes a standard albedo of 0.23 and calculates a diameter of 7.22 kilometers based on anabsolute magnitude of 12.92.[3]
Thisminor planet was named "Prisma" (prism) in honour of theBergedorf Spectral Catalogue (German:Bergedorfer Spektralkatalog), as prisms are one method of obtaining spectra.[2] The official naming citation was also published inPaul Herget'sThe Names of the Minor Planets in 1955 (H 111).[2]
