Rotation period A rotational
lightcurve of
Ankara was obtained from photometric observations by French amateur astronomer
René Roy in September 2004. Lightcurve analysis gave a
rotation period of 31.8 hours with a brightness variation of 0.21
magnitude (). While not being a
slow rotator,
Ankaras spin rate is slower than that of most asteroids, which typically rotate within 20 hours once around their axis.
Diameter and albedo According to the surveys carried out by the Japanese
Akari satellite, and NASA's
Wide-field Infrared Survey Explorer with its subsequent
NEOWISE mission,
Ankara measures between 17.834 and 19.82 kilometers in diameter and its surface has an
albedo between 0.258 and 0.320. The
Collaborative Asteroid Lightcurve Link (CALL) assumes a lower albedo of 0.10—a compromise value that lies between the albedos for
stony (0.20) and
carbonaceous (0.057) asteroids, chosen by CALL for all non-family asteroids with a
semi-major axis between 2.6 and 2.7 AU—and consequently calculates a larger diameter of 29.08 kilometers with an
absolute magnitude of 10.8, as a body's diameter and albedo are inversely related to each other. == Naming ==