Discovered by K. Korlević
M. Jurić MPC designation 22899 Alconrad Minor planet category main-belt · Koronis Aphelion 3.08 m Asteroid family Koronis family Asteroid group Asteroid belt | Discovery date 11 October 1999 Alternative names 1999 TO14 · 1998 ML48 Discovered 11 October 1999 Inclination 2.882° Discovery site Višnjan Observatory | |
Named after Albert R. Conrad
(astronomer, AO-expert) Discoverers Mario Jurić, Korado Korlević | ||
22899 Alconrad, provisional designation 1999 TO14, is a binary Koronian asteroid from the outer region of the asteroid belt, approximately 5 kilometers in diameter. It was discovered on 11 October 1999, by Croatian astronomers Korado Korlević and Mario Jurić at the Višnjan Observatory, Croatia. When the asteroid moon S/2003 (22899) 1 was discovered in 2003, it was the smallest known binary system in the main-belt.
Description
The stony S-type asteroid belongs to the Koronis family, a collisional group consisting of a few hundred known bodies with nearly ecliptical orbits. It orbits the Sun at a distance of 2.6–3.1 AU once every 4 years and 10 months (1,752 days). Its orbit has an eccentricity of 0.08 and an inclination of 3° with respect to the ecliptic. A precovery was taken by Steward Observatory's Spacewatch program in 1994, extending Alconrad's observation arc by 5 years prior to its discovery observation.
In December 2009, a rotational light-curve was obtained from photometric observations at the ground-based Wise Observatory in Mitzpe Ramon, Israel. The light-curve gave it a rotation period of 7000403000000000000♠4.03±0.03 hours with a brightness variation of 6999190000000000000♠0.19±0.03 in magnitude (U=2). In October 2013, another observation in the R-band at the U.S Palomar Transient Factory derived a longer period of 7000502060000000000♠5.0206±0.0029 with an ampliutude of 6999140000000000000♠0.14 in magnitude (U=2).
According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Alconrad measures 5.7 kilometers in diameter and its surface has an albedo of 0.18, while he Collaborative Asteroid Lightcurve Link assumes a standard albedo for members of the Koronis family of 0.24 and calculates a diameter of 4.9 kilometers. In October 2003, when the asteroid moon S/2003 (22899) 1 was discovered by the researchers at Southwest Research Institute using the Hubble Space Telescope, they calculated a diameter of 4.5 kilometers for the primary, based on an assumed albedo of 0.21. The researchers also measured a large angular separation of 0".14 between Alconrad and its moon. This is equivalent to a distance of 170 kilometers, or 182 kilometers, when using a/Rp ratio of 81. Based on a difference in magnitude of 2.5, the satellite measures 1 to 1.5 kilometers in diameter.
The minor planet was named in honor of American astronomer Albert R. Conrad (b. 1953) who worked at various observatories in the United States. Expert in and developer of adaptive optics, he has studied the natural satellites of the Solar System for their shape and topography, and co-discovered many asteroid moons in the process. Naming citation was published on 20 June 2016 (M.P.C. 100606).