Discovered by C. Shoemaker Alternative names 1988 BY1 · 1985 US2 Orbits Sun MPC designation 5028 | Discovery date 23 January 1988 Discovered 23 January 1988 Discoverer Carolyn S. Shoemaker | |
Pronunciation həˈliːsəs(hə-lee'-səs) Similar Jupiter trojan, Sun, Solar System, 5381 Sekhmet, 3554 Amun | ||
5028 Halaesus (hə-lee'-səs), provisional designation 1988 BY1, is a Jupiter trojan from the Greek camp, approximately 51 kilometers in diameter. It was discovered by American astronomer Carolyn Shoemaker at the U.S. Palomar Observatory, California, on 23 January 1988.
The asteroid is orbiting in the leading Greek camp at Jupiter's L4 Lagrangian point, 60° ahead of its orbit (see Trojans in astronomy). The carbonaceous C-type body has also been rated as a rare D-type asteroid by a large-scale survey performed by Pan-STARRS. It orbits the Sun at a distance of 4.6–5.9 AU once every 12 years and 1 month (4,410 days) with an eccentricity of 0.13 and an inclination of 21° in respect of the ecliptic.
In September 1996, the body was observed by Stefano Mottola using the now decommissioned Bochum 0.61-metre Telescope at ESO's La Silla Observatory in Chile. The resulting rotational light-curve showed a well-defined period of 7001249370000000000♠24.937±0.015 hours with a brightness variation of 6999290000000000000♠0.29±0.01 in magnitude (U=3). According to the surveys carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, the asteroid measures 55.8 kilometers in diameter and its surface has a typically low albedo of 0.057.
The minor planet was named from Greek mythology after Halaesus, a son of king Agamemnon, after whom the asteroid 911 Agamemnon is named.