_Appenzella.png) Shape model ofAppenzella from itslightcurve | |
| Discovery[1] | |
|---|---|
| Discovered by | P. Wild |
| Discovery site | Zimmerwald Obs. |
| Discovery date | 23 September 1965 |
| Designations | |
| (1768) Appenzella | |
Named after | Appenzell(canton)[2] |
| 1965 SA · 1934 PM 1942 TH | |
| main-belt · Nysa[3] | |
| Orbital characteristics[1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 74.56 yr (27,232 days) |
| Aphelion | 2.8899AU |
| Perihelion | 2.0141 AU |
| 2.4520 AU | |
| Eccentricity | 0.1786 |
| 3.84yr (1,402 days) | |
| 175.69° | |
| 0° 15m 24.12s / day | |
| Inclination | 3.2582° |
| 12.423° | |
| 19.718° | |
| Physical characteristics | |
| Dimensions | 19.0±1.9 km[4] 19.30±0.17 km[5] 20.221±0.129 km[6][7] 20.86±2.3 km(IRAS:2)[8] 21±2 km[9] |
| 5.18335±0.00001h[10] 5.1839±0.0001 h[11] | |
| 0.03±0.01[9] 0.032±0.007[6][7] 0.0338±0.009(IRAS:2)[8] 0.039±0.008[5] 0.04±0.01[4] | |
| F(Tholen)[1] C(SMASS)[1] B–V = 0.615[1] U–B = 0.230[1] | |
| 12.70[1][3][4][5][6][9] | |
1768 Appenzella (prov. designation:1965 SA) is a rare-typeNysian asteroid from the inner regions of theasteroid belt, approximately 20 kilometers in diameter. It was discovered on 23 September 1965, by Swiss astronomerPaul Wild atZimmerwald Observatory near Bern, Switzerland.[12] It was later named after the Swiss canton ofAppenzell.[2]
Appenzella is a darkcarbonaceous asteroid and a member of the Polanian subgroup of theNysa family. On theTholen taxonomic scheme, it belongs to the small group of 28 bodies known to have aF-type spectrum.[13]
It orbits the Sun in theinner main-belt at a distance of 2.0–2.9 AU once every 3 years and 10 months (1,402 days). Its orbit has aneccentricity of 0.18 and aninclination of 3° with respect to theecliptic.[1] The first used[clarification needed] observation was made at the FinnishTurku Observatory in 1942, extending the asteroid'sobservation arc by 23 years prior to its discovery.[12]
In November 2011, a rotationallightcurve ofAppenzella was obtained by French astronomerRené Roy at his Blauvac Observatory (627) in southeastern France. Lightcurve analysis gave a well-definedrotation period of5.1839 hours with a brightness variation of 0.53magnitude (U=3).[11] In 2016, remodeled photometric data from the Lowell database gave in a very similar period of 5.18335 hours.[10]
Based on the surveys carried out by NASA'sWide-field Infrared Survey Explorer and its subsequentNEOWISE mission, the asteroid measures between 19.0 and 21 kilometers in diameter and its surface has a lowalbedo between 0.03 and 0.04.[4][5][6][7][8][9] TheCollaborative Asteroid Lightcurve Link agrees with the results obtained by the Infrared Astronomical Satellite,IRAS, which found an albedo of 0.034 and a mean diameter of 20.9 kilometers, with anabsolute magnitude of 12.7.[1][3]
In 1971,Appenzella was named by the discoverer in honor of the ruralSwiss canton ofAppenzell, during the celebration of the 150th anniversary of the public middle school "Kantonsschule Trogen",Appenzell Ausserrhoden, founded in 1821.[2][14] The officialnaming citation was published by theMinor Planet Center on 1 July 1972 (M.P.C. 3297).[15]
