Discovered by B. Jekhovsky MPC designation 988 Appella Discovered 10 November 1922 Discovery site Algiers Observatory | Discovery date 10 November 1922 Alternative names 1922 MT · 1955 QJ1 Observation arc 76.56 yr (27,964 days) Orbits Sun | |
Named after Paul Émile Appell (mathematician) Similar 193 Ambrosia, 516 Amherstia, 276 Adelheid, 441 Bathilde, 958 Asplinda | ||
988 Appella, provisional designation 1922 MT, is a dark Themistian asteroid and slow rotator from the outer region of the asteroid belt, about 26 kilometers in diameter. It was discovered on 10 November 1922, by Russian–French astronomer Benjamin Jekhowsky at Algiers Observatory in Algeria, North Africa.
The asteroid is a member of the Themis family, a dynamical family of outer-belt asteroids with nearly coplanar ecliptical orbits. It orbits the Sun at a distance of 2.4–3.9 AU once every 5 years and 7 months (2,035 days). Its orbit has an eccentricity of 0.24 and an inclination of 2° with respect to the ecliptic. In 2012, a photometric light-curve analysis at the U.S. Santana Observatory in California (646) gave a long rotation period of 120 hours with a brightness amplitude of 0.4 in magnitude, rendering a tentative 2006-observation by Italian astronomers Roberto Crippa and Federico Manzini obsolete.
According to the surveys carried out by the Infrared Astronomical Satellite, IRAS, the Japanese Akari satellite, and the U.S. Wide-field Infrared Survey Explorer with its NEOWISE mission, the asteroid's surface has an albedo in the range of 0.07 to 0.14. Although the Collaborative Asteroid Lightcurve Link (CALL) derives a low albedo in accordance with the space-based surveys, CALL classifies the dark Themistian body as a stony S-type rather than a carbonaceous C-type asteroid.
The minor planet was named in honor of French mathematician Paul Émile Appel (1855–1930), president of the Academy of Sciences and of the Société Astronomique de France, and the author of Traité de Mécanique Rationelle published in 1893. Naming citation was first published by Paul Herget in The Names of the Minor Planets in 1955 (H 94).