 In November 2004, a rotational lightcurve of "Aethusa" was obtained from photometric observations by French amateur astronomer René Roy at Blauvac Observatory ().Lightcurve analysis gave a rotation period of 12.916 hours with a brightness variation of 0.12 magnitude (), while in March 2006, astronomer Brian Warner at his Palmer Divide observatory in Colorado, United States, obtained a shorter period of 8.621 hours and an amplitude of 0.18 magnitude ().According to the surveys carried out by the Infrared Astronomical Satellite IRAS, the Japanese Akari satellite, the MIPS photometer on the Spitzer Space Telescope, and the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, "Aethusa" measures between 17.42 and 25.361 kilometers in diameter and its surface has an albedo between 0.160 and 0.3202.