The Alinement of Asteroid Rotation

Abstract

Data have been accumulating since the beginning of this century that indicate that most, if not all, large asteroids have periodic lightcurves. The variations that are seen have periods of the order of several hours and can be understood as being caused by bodily rotation, accompanied by changes in shape and/or surface properties. Because corresponding color changes are usually absent, the former explanation of a variation in cross section is probably the correct one.