According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Azabu measures 10.2 kilometers in diameter and its surface has an albedo between 0.32. The Collaborative Asteroid Lightcurve Link assumes a much lower carbonaceous standard albedo of 0.057 (based on the Masi Foglia Binzel taxonomy) and consequently calculates a much larger diameter of 21.16 kilometers with an absolute magnitude of 12.1.
