Orus is planned to be visited by the Lucy spacecraft which was launched in 2021. The flyby is scheduled for 20 November 2028, and will approach the asteroid to a distance of 1,000 km (620 mi) at a relative velocity of 7.1 km/s (16,000 mph).[9]
Orus is characterized as a D-type and C-type asteroid by the Lucy mission team and by Pan-STARRS photometric survey, respectively.[9][8] It has a V–I color index of 0.95, seem among most larger D-type Jupiter trojans.[7]
The first photometric observations of Orus have been made in October 2009, by astronomer Stefano Mottola in a photometric lightcurve survey of 80 Jupiter trojans, using the 1.2-meter telescope at Calar Alto Observatory. The obtained rotational lightcurve rendered a periodof13.45±0.08 hours with a brightness variation of 0.18 magnitude (U=2).[7][10]
In 2016, Mottola published a revised rotation period of 13.48617±0.00007h, from ground-based observations taken over five apparitions in support of the Lucy mission. He finds that Orus is a retrograde rotator. The lightcurve suggests the presence of a large crater in the proximity of its north pole.[11]
According to the surveys carried out by the Japanese Akari satellite and the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, the body has an albedo of 0.083 and 0.075, with a diameter of 53.87 and 50.81 kilometers, respectively.[12][13] The Collaborative Asteroid Lightcurve Link assumes a standard albedo for carbonaceous C-type asteroids of 0.057 and calculates a diameter of 55.67 kilometers with an absolute magnitude of 10.0.[7]
Orus has a candidate satellite, detected while searching through Hubble images taken on 7–8 August 2018.[16] Further observations are needed to determine physical characteristics of the satellite, which can help measure the mass of the primary.
^Mottola, Stefano; Marchi, Simone; Buie, Marc W.; Hellmich, Stephan; Di Martino, Mario; Proffe, Gerrit; Levison, Harold F.; Zangari, Amanda Marie (2016). "Ground-based characterization of Eurybates and Orus, two fly-by targets of the Lucy Discovery mission". AAS/Division for Planetary Sciences Meeting Abstracts #48. 48. DPS meeting #48: 208.04. Bibcode:2016DPS....4820804M.
^Usui, Fumihiko; Kuroda, Daisuke; Müller, Thomas G.; Hasegawa, Sunao; Ishiguro, Masateru; Ootsubo, Takafumi; et al. (October 2011). "Asteroid Catalog Using Akari: AKARI/IRC Mid-Infrared Asteroid Survey". Publications of the Astronomical Society of Japan. 63 (5): 1117–1138. Bibcode:2011PASJ...63.1117U. doi:10.1093/pasj/63.5.1117. (online, AcuA catalog p. 153)