| Discovery[1] | |
|---|---|
| Discovered by | K. Reinmuth |
| Discovery site | Heidelberg Obs. |
| Discovery date | 5 January 1930 |
| Designations | |
| (1162) Larissa | |
| Pronunciation | /ləˈrɪsə/[2] |
Named after | Larissa(Greek city)[3] |
| 1930 AC · 1948 KJ | |
| main-belt · (outer)[1] Hilda[4][5] | |
| Orbital characteristics[1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 87.50 yr (31,958 days) |
| Aphelion | 4.3705AU |
| Perihelion | 3.5082 AU |
| 3.9393 AU | |
| Eccentricity | 0.1095 |
| 7.82yr (2,856 days) | |
| 315.27° | |
| 0° 7m 33.96s / day | |
| Inclination | 1.8856° |
| 39.808° | |
| 209.55° | |
| Jupiter MOID | 0.6683 AU |
| Physical characteristics | |
| Dimensions | 41.3±0.9 km[6] 42.243±0.111 km[6] 44.32 km(derived)[4] 48.59±1.50 km[7] |
| 6.514±0.003 h[8][a] 6.516±0.002 h[9] 6.520±0.0021 h[10] 13.0h(dated)[11] | |
| 0.1153(derived)[4] 0.127±0.009[7] 0.169±0.012[6] 0.18±0.03[6] | |
| Tholen = P[1][4] · M[6] B–V = 0.761[1] U–B = 0.226[1] | |
| 9.314±0.001(R)[10] · 9.40[6] · 9.42±0.43[12] · 9.44[1][7] · 9.73[4][13] | |
1162 Larissa, provisional designation1930 AC, is a metallic Hildianasteroid from the outermost regions of theasteroid belt, approximately 43 kilometers in diameter. It was discovered on 5 January 1930, by German astronomerKarl Reinmuth atHeidelberg Observatory in southwest Germany.[14] The asteroid was named after the Greek city ofLarissa.[3]
Larissa belongs to theHilda group locatedoutermost part of the main-belt.[4] Asteroids in this dynamical group have semi-major axis between 3.7 and 4.2 AU and stay in a 3:2resonance with the gas giant Jupiter.Larissa, however, is abackground asteroid and not a member of the (collisional)Hilda family (101).[5]
The asteroid orbits the Sun at a distance of 3.5–4.4 AU once every 7 years and 10 months (2,856 days). Its orbit has aneccentricity of 0.11 and aninclination of 2° with respect to theecliptic.[1] The body'sobservation arc begins 15 days after its official discovery observation at Heidelberg.[14]
Larissa has been characterized as a metallicM-type asteroid by theWide-field Infrared Survey Explorer (WISE).[6] In theTholen classification, the asteroid a primitiveP-type asteroid, which typically have lower albedos than those measured by WISE and Akari(see below).[1]
In April 2017, a rotationallightcurve ofLarissa was obtained from photometric observations by American astronomersBrian Warner andRobert Stephens at the Center for Solar System Studies (U81/U82) in California. Lightcurve analysis gave a well-definedrotation period of 6.514 hours with a brightness variation of 0.12magnitude (U=3).[8][a]
In May 2010, a lightcurve form the Oakley Southern Sky Observatory (E09) in Australia, gave a concurring period of 6.516 hours with an amplitude of 0.20 magnitude (U=3).[9] Another period of 6.520 hours (Δ0.12 mag) was measured at thePalomar Transient Factory in October 2012 (U=2).[10] The first photometric observation ofLarissa, which gave a period of 13.0 hours, is now considered incorrect (U=1).[11]
According to the surveys carried out by the JapaneseAkari satellite and theNEOWISE mission of NASA's WISE telescope,Larissa measures between 41.3 and 48.59 kilometers in diameter and its surface has analbedo between 0.127 and 0.18.[6][7] TheCollaborative Asteroid Lightcurve Link derives an albedo of 0.1153 and a diameter of 44.32 kilometers based on anabsolute magnitude of 9.73.[4]
Thisminor planet was named for the city ofLarissa, capital of theThessaly region in Greece, after which the asteroid1161 Thessalia was named. The name was also given toLarissa (Neptune VII), one of themoons of Neptune. The official naming citation was mentioned inThe Names of the Minor Planets byPaul Herget in 1955 (H 108).[3]
