1768 Appenzella

1768 Appenzella, provisional designation 1965 SA, is a rare-type Nysa asteroid from the inner regions of the asteroid belt, approximately 20 kilometers in diameter. It was discovered on 23 September 1965, by Swiss astronomer Paul Wild at Zimmerwald Observatory near Bern, Switzerland.

The dark carbonaceous asteroid is a member of the Polanian subgroup of the Nysa family. On the Tholen taxonomic scheme, it belongs to the small group of 28 bodies known to have a F-type spectrum. It orbits the Sun at a distance of 2.0–2.9 AU once every 3 years and 10 months (1,402 days). Its orbit has an eccentricity of 0.18 and an inclination of 3° with respect to the ecliptic. The first used observation was made at the Finnish Turku Obervatory in 1942, extending the asteroid's observation arc by 23 years prior to its discovery.

In November 2011, a rotational light-curve obtained by French astronomer René Roy at the Blauvac Observatory (627) in southeastern France gave a well-defined a rotation period of 7000518390000000000♠5.1839±0.0001 hours with a brightness variation of 0.53 in magnitude (U=3). In 2016, remodeled photometric data from the Lowell database resulted in a very similar period of 5.18335 hours.

Based on the surveys carried out by NASA's Wide-field Infrared Survey Explorer and its subsequent NEOWISE mission, the asteroid measures between 19.0 and 21 kilometers in diameter and its surface has a low albedo between 0.03 and 0.04. The Collaborative 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, based on an absolute magnitude of 12.7.

In 1971, Appenzella was named by the discoverer in honor of the rural Swiss Canton of Appenzell, during the treat of the 150th anniversary of the public middle school "Kantonsschule Trogen", Appenzell Ausserrhoden, founded in 1821. Naming citation was published before November 1977 (M.P.C. 3297).