 Photometric observations of this asteroid during 1997 were used to build a lightcurve showing a rotation period of hours with a brightness variation of magnitude.A 2009 study yielded a period of hours, in reasonable agreement with the previous result.According to the 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, "Agamemnon" measures between 131.04 and 185.30 kilometers in diameter, based on a common absolute magnitude of 7.89 and a surface albedo between 0.037 and 0.072.