Modelled shape of Prisma from its lightcurve | |
| 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 | 2.9762 AU |
| Perihelion | 1.7561 AU |
| 2.3661 AU | |
| Eccentricity | 0.2578 |
| 3.64 yr (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] 6.558 h [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 designation 1931 FE, is an elongated Phocaea asteroid from the inner regions of the asteroid belt, approximately 7 kilometers in diameter. It was discovered by German astronomer Friedrich Schwassmann at the Bergedorf Observatory in Hamburg on 17 March 1931. [12] The asteroid was named after the Bergedorf Spectral Catalogue, an astronomical catalog. [2]
Prisma is a member of the Phocaea family ( 701 ), a prominent family of S-type asteroids with their largest members being 25 Phocaea and 587 Hypsipyle. There are many Mars-crossers among this family of relatively eccentric inner 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 an eccentricity of 0.26 and an inclination of 24° with respect to the ecliptic. [1] The body's observation arc begins at Bergedorf, one week after its official discovery observation. [12]
Photometric observations of Prisma gave a well defined rotational lightcurve with a period between 6.546 and 6.558 hours and a high brightness variation of 0.85–1.16 magnitude, 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 a spin axis of (133.0°, −78.0°) in ecliptic coordinates (λ, β) ( Q=n.a. ). [9] [10]
According to the surveys carried out by the Japanese Akari satellite, and NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Prisma measures between 7.38 and 9.27 kilometers in diameter and its surface has an albedo between 0.144 and 0.220. [5] [6] The Collaborative Asteroid Lightcurve Link assumes a standard albedo of 0.23 and calculates a diameter of 7.22 kilometers based on an absolute magnitude of 12.92. [3]
This minor planet was named "Prisma" (prism) in honour of the Bergedorf Spectral Catalogue (German : Bergedorfer Spektralkatalog), as prisms are one method of obtaining spectra. [2] The official naming citation was also published in Paul Herget's The Names of the Minor Planets in 1955 ( H 111 ). [2]