Discovered by C. W. Juels MPC designation 24101 Cassini Discovered 9 November 1999 Orbits Sun Asteroid group Asteroid belt | Discovery date 9 November 1999 Minor planet category main-belt · (middle) Absolute magnitude 12.9 Discoverer Charles W. Juels | |
Named after Giovanni Cassini
(astronomer) Alternative names 1999 VA9 · 1926 XH
1926 YB · 1986 RS16
1986 TM15 Discovery site Fountain Hills Observatory Similar Sun, Solar System, Iapetus, Rhea, Tethys | ||
24101 Cassini, provisional designation 1999 VA9, is an eccentric, stony asteroid from the middle region of the asteroid belt, approximately 7 kilometers in diameter. It was discovered on 9 November 1999, by American amateur astronomer Charles Juels at the U.S. Fountain Hills Observatory (), Arizona.
The S-type asteroid orbits the Sun at a distance of 1.8–3.5 AU once every 4 years and 4 months (1,571 days). Its orbit has an eccentricity of 0.31 and an inclination of 15° with respect to the ecliptic. Cassini was first identified as 1926 XH at Heidelberg Observatory in 1926. The first used observation was a precovery obtained at ESO's La Silla Observatory in 1992, which extends Cassini's observation arc by 7 years prior to its official discovery observation.
In February 2009, two rotational light-curves were obtained from photometric observations made at the private U.S. Shed of Science Observatory (H39), Minnesota, and by Italian astronomer Silvano Casulli, respectively. The light-curves rendered a well-defined rotation period of 7000398600000000000♠3.986±0.001 hours with a brightness variation of 0.12 magnitude (U=3/-3). According to observations carried out by the NEOWISE mission of NASA's space-based Wide-field Infrared Survey Explorer, the asteroid measures 7.1 kilometer in diameter and its surface has an albedo of 0.25. However, the Collaborative Asteroid Lightcurve Link (CALL) assumes an untypically low albedo of only 0.10 and correspondingly, calculates a diameter of 11.1 kilometers, as the lower the body's albedo (reflectivity), the larger its diameter at a constant absolute magnitude (brightness).
The minor planet was named in honor of Italian-born French astronomer Giovanni Cassini (1625–1712), who was the first director of the Paris Observatory from 1671 until his death. He discovered the four moons of Saturn – Iapetus, Rhea, Tethys and Dione – the major gap in its rings, known as Cassini Division, and was the first to write down observations of the zodiacal light. The Cassini–Huygens spacecraft is named after him and Christiaan Huygens. The lunar and Martian craters Cassini are also named in his honor. Naming citation was published on 21 September 2002 (M.P.C. 46684).