Discovered by LINEAR MPC designation 19741 Callahan Minor planet category main-belt · (inner) Absolute magnitude 14.89 Discovery site Experimental Test Site | Discovery date 5 January 2000 Alternative names 2000 AN141 · 1978 RQ8 Discovered 5 January 2000 Orbits Sun Asteroid group Asteroid belt | |
Named after Diane Callahan(mentor at DCYSC) Discoverer Lincoln Near-Earth Asteroid Research | ||
19741 Callahan, provisional designation 2000 AN141, is a stony asteroid from the inner regions of the asteroid belt, approximately 3.5 kilometers in diameter. It was discovered on 5 January 2000, by the Lincoln Near-Earth Asteroid Research, LINEAR, at the Lincoln Laboratory's Experimental Test Site, Socorro, New Mexico.
The S-type asteroid orbits the Sun at a distance of 2.0–2.5 AU once every 3 years and 4 months (1,231 days). Its orbit has an eccentricity of 0.13 and an inclination of 8° with respect to the ecliptic. Callahan was first identified as 1978 RQ8 at ESO's La Silla Observatory in 1978, which extends the asteroid's observation arc by 22 years prior to its official discovery observation.
In December 2009, a rotational light-curve for this asteroid was obtained from photometric observations at the U.S. Palomar Transient Factory, California. It gave a rotation period of 7000726840000000000♠7.2684±0.0015 hours with a relatively high brightness variation of 0.81 in magnitude (U=2), indicative of a non-spherical shape. According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Callahan measures 3.9 kilometers in diameter and its surface has an albedo of 0.22. The Collaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20 and calculates a diameter of 3.1 kilometers, based on an absolute magnitude of 14.89.
The minor planet was named after Diane Callahan, teacher at U.S. Fairfield Middle School, Ohio, who mentored a finalist in the 2003 Discovery Channel Youth Science Challenge (DCYSC), a middle school science competition. Naming citation was published on 10 October 2003 (M.P.C. 49772).