In the SDSS-based taxonomy, Idomeneus is a D-type asteroid.[11][13]Pan-STARRS' survey has also characterized it as a dark D-type, while the Collaborative Asteroid Lightcurve Link (CALL) assumes it to be a C-type.[10] Its V–I color index of 0.91, however, is typical for most larger D-type Jupiter trojans.[12]
The observations also indicated that Idomeneus is a binary asteroid with a minor-planet moon in its orbit. The satellite's orbital period is 19.295±0.005 hours, or alternatively, 32.17±0.02 hours with a brightness variation of 0.14 magnitude. However, the results are tentative and have not been published in any journal as of 2018.[12][a]
Diameter and albedo
According to the surveys carried out by the Japanese Akari satellite, the Infrared Astronomical Satellite IRAS, and the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Idomeneus measures between 52.55 and 61.01 kilometers in diameter and its surface has an albedo between 0.0571 and 0.078.[6][7][8] CALL derives an albedo of 0.0521 and a diameter of 60.95 kilometers based on an absolute magnitude of 9.9.[12]
100+ largest Jupiter trojans
Largest Jupiter Trojans by survey(A) (mean-diameter in kilometers; YoD: Year of Discovery)
Note: missing data was completed with figures from the JPL SBDB (query) and from the LCDB (query form) for the WISE/NEOWISE and SIMPS catalogs, respectively. These figures are given in italics. Also, listing is incomplete above #100.
^ abcLightcurve plot of (2759) Idomeneus, by B. D. Warner at CS3 (U82), with a rotation period 479±5 hours and an amplitude of 0.19±0.02 mag. Quality code of 2+. The orbital period for the secondary of the suspected binary asteroid is 19.295±0.005 hours, or alternatively, 32.17±0.02 hours. Summary figures at the LCDB.
^ abcdUsui, 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)
^ abcTedesco, E. F.; Noah, P. V.; Noah, M.; Price, S. D. (October 2004). "IRAS Minor Planet Survey V6.0". NASA Planetary Data System – IRAS-A-FPA-3-RDR-IMPS-V6.0. 12: IRAS-A-FPA-3-RDR-IMPS-V6.0. Bibcode:2004PDSS...12.....T. Retrieved 16 June 2018.