Discovered by M. Wolf MPC designation 1661 Granule Discovered 31 March 1916 Asteroid group Asteroid belt | Discovery date 31 March 1916 Orbits Sun | |
Named after Edward Gall (pathologist) Alternative names A916 FA · 1936 PM1949 QG1 · 1949 SJ1961 DB Discovery site Landessternwarte Heidelberg-Königstuhl Similar 528 Rezia, 509 Iolanda, 417 Suevia, 540 Rosamunde, 484 Pittsburghia | ||
1661 Granule, also designated A916 FA, is a stony Florian asteroid from the inner regions of the asteroid belt, approximately 7 kilometers in diameter. It was discovered on 31 March 1916, by German astronomer Max Wolf at Heidelberg Observatiry in southern Germany.
The S-type asteroid is a member of the Flora family, a large collisional population of stony asteroids in the main-belt. It orbits the Sun at a distance of 2.0–2.4 AU once every 3 years and 3 months (1,178 days). Its orbit has an eccentricity of 0.09 and an inclination of 3° with respect to the ecliptic. Granule's observation arc begins with its observation at Bergedorf Observatory, one month after its official discovery observation. (It is unclear whether "HD 17", Message from Heidelberg Observatory #17, is the official discovery observation due to a different time stamp).
In January 2006, the first rotational light-curve of Granule was obtained from photometric observations by French amateur astronomer René Roy. It gave a longer-than average rotation period of 24 hours with a brightness variation of 0.15 magnitude (U=2). No other light-curves have been obtained yet.
Granule has neither been observed by the Infrared Astronomical Satellite IRAS, nor the Japanese Akari satellite, nor NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission. The Collaborative Asteroid Lightcurve Link assumes an albedo of 0.24 – derived from the family's principal body and namesake, the asteroid 8 Flora – and calculates a diameter of 7.14 kilometers using an absolute magnitude of 12.9.
This minor planet was named in honor of Edward Gall, an internationally renowned American pathologist, former director of the University of Cincinnati Academic Health Center and president of USCAP. It was named on the occasion of his retirement to commemorate his career and his discovery of the Gall's granule, a feature of lymphocytes. Naming citation was published before November 1977 (M.P.C. 3757).