|Discovered by H. Debehogne|
MPC designation (6090) 1989 DJ
Discovered 27 February 1989
Discovery site La Silla Observatory
|Discovery date 27 February 1989|
Observation arc 62.18 yr (22,713 days)
Absolute magnitude 9.4
Discoverer Henri Debehogne
Asteroid group Jupiter trojan
|Alternative names 1989 DJ · 1977 EH2
1983 OH · 1990 FO1|
Minor planet category Jupiter trojan (Trojan camp)
(6090) 1989 DJ is a carbonaceous Jupiter trojan from the Greek camp, approximately 70 kilometers in diameter. It was discovered on 27 February 1989, by Belgian astronomer Henri Debehogne at ESO's La Silla Observatory in northern Chile.
The dark C-type asteroid is orbiting in the leading Greek camp at Jupiter's L4 Lagrangian point, 60° ahead of its orbit (see Trojans in astronomy). It orbits the Sun at a distance of 5.0–5.6 AU once every 12 years and 3 months (4,471 days). Its orbit has an eccentricity of 0.06 and an inclination of 20° with respect to the ecliptic. The first precovery was taken at Palomar Observatory in 1954, extending the body's observation arc by 35 years prior to its discovery.
Italian astronomer Stefano Mottola obtained two concurring rotational light-curves for this asteroid from photometric observations. In June 1994, together with astronomer Anders Erikson, he constructed a light-curve from observations made with the 0.9-meter Dutch telescope at La Silla, showing a rotation period of 7001186000000000000♠18.60±0.05 hours and a brightness variation of 6998900000000000000♠0.09±0.01 magnitude (U=2+). In September 2009, he used the 1.2-meter reflector at Calar Alto Observatory, Spain, to obtain a period of 7001184760000000000♠18.476±0.007 hours with an amplitude of 6999160000000000000♠0.16±0.01 in magnitude (U=2+), confirming his previous result.
According to the space-based surveys carried out by the Infrared Astronomical Satellite IRAS, the Japanese Akari satellite, and the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, the asteroid measures between 59 and 82 kilometers in diameter and its surface has an albedo between 0.046 and 0.087. The Collaborative Asteroid Lightcurve Link agrees with the results from IRAS, that is an albedo of 0.0553 and a diameter of 74.5 kilometers, based on an absolute magnitude of 9.4, while Stefano Mottola estimated a diameter of 78 kilometers.