Like Mathilde, its density appears to be unusually low, indicating that it may be a loosely packed rubble pile, not a monolithic object.

[16] Lightcurve analysis indicates that Eugenia's pole most likely points towards ecliptic coordinates (β, λ) = (−30°, 124°) with a 10° uncertainty,[6] which gives it an axial tilt of 117°.

In November 1998, astronomers at the Canada–France–Hawaii Telescope on Mauna Kea, Hawaii, discovered a small moon orbiting Eugenia.

[17] A second, smaller (estimated diameter of 6 km) satellite that orbits closer to Eugenia than Petit-Prince has since been discovered and provisionally named S/2004 (45) 1.

[18] It was discovered by analyses of three images acquired in February 2004 from the 8.2 m VLT "Yepun" at the European Southern Observatory (ESO) Cerro Paranal, in Chile.