| Discovery[1] | |
|---|---|
| Discovered by | L. Volta |
| Discovery site | Pino Torinese Obs. |
| Discovery date | 11 February 1931 |
| Designations | |
| (1191) Alfaterna | |
| Pronunciation | /ælfəˈtɜːrnə/[2] |
Named after | Nuceria Alfaterna (ancient Roman town)[3] |
| 1931 CA · 1965 AA | |
| main-belt · (outer)[4] | |
| Orbital characteristics[1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 85.79 yr (31,335 days) |
| Aphelion | 3.0286AU |
| Perihelion | 2.7567 AU |
| 2.8927 AU | |
| Eccentricity | 0.0470 |
| 4.92yr (1,797 days) | |
| 178.01° | |
| 0° 12m 1.08s / day | |
| Inclination | 18.491° |
| 134.73° | |
| 53.411° | |
| Physical characteristics | |
| Dimensions | 38.92±13.94 km[5] 42.01 km(derived)[4] 42.09±3.0 km[6] 43.38±14.16 km[7] 46.11±0.63 km[8] 46.375±0.836 km[9] 47.397±0.175 km[10] |
| 3.664h(removed)[4][a] 33.12±1.92(tentative)[11] | |
| 0.0297±0.0053[9] 0.04±0.02[7] 0.04±0.05[5] 0.045±0.008[10] 0.0479(derived)[4] 0.050±0.002[8] 0.0574±0.009[6] | |
| C[4] | |
| 10.60[6][8][9] · 10.77[7] · 10.8[1][4][5] · 10.89±0.21[12] | |
1191 Alfaterna, provisional designation1931 CA, is a carbonaceousasteroid from the outer region of theasteroid belt, approximately 43 kilometers in diameter. It was discovered on 11 February 1931, by Italian astronomerLuigi Volta at theObservatory of Turin in northwestern Italy.[13] The asteroid was named for the ancient Roman town ofNuceria Alfaterna.[3]
Alfaterna orbits the Sun in theouter main-belt at a distance of 2.8–3.0 AU once every 4 years and 11 months (1,797 days). Its orbit has aneccentricity of 0.05 and aninclination of 18° with respect to theecliptic.[1]
The first unused observation was taken atHeidelberg two nights prior to its discovery. The body'sobservation arc begins at Pino Torinese one week after its official discovery observation.[13]
Alfaterna has been characterized as a carbonaceousC-type asteroid.[4]
From 2005 to 2015, several astronomers such asDonald Pray, Henk de Groot andRaoul Behrend, Federico Manzini, as well asLaurent Bernasconi unsuccessfully tried to obtain a well-definedlightcurve ofAlfaterna. While Pray derived a period of 3.664 hours with an amplitude of 0.05 magnitude (U=1),[a] the European astronomers published a tentative period of 33.12 hours (U=n.a.).[11] As of 2017, the body's spin rate effectively remains unknown.[4]
According to the surveys carried out by the Infrared Astronomical SatelliteIRAS, the JapaneseAkari satellite, and NASA'sWide-field Infrared Survey Explorer with its subsequentNEOWISE mission,Alfaterna measures between 38.92 and 47.397 kilometers in diameter and its surface has analbedo between 0.04 and 0.0574 (without preliminary results).[5][6][7][8][9][10] TheCollaborative Asteroid Lightcurve Link derives an albedo of 0.0479 and a diameter of 42.01 kilometers using anabsolute magnitude of 10.8.[4]
Thisminor planet is named for the ancient Roman town of "Nuceria Alfaterna", where now the townNocera Inferiore/Superiore is located. The ancient city was founded between Pompeii and Salerno in 10th century BC. In 1957, the name was suggested by astronomer Alfonso Fresa at Turin Observatory.[3] The officialnaming citation was published by theMinor Planet Center on 15 July 1968 (M.P.C. 2882).[14]
