Prothoon is an assumed
C-type asteroid.
Rotation period In August 2011, a rotational
lightcurve of
Prothoon was obtained from
photometric observations by
Robert Stephens at the Goat Mountain Astronomical Research Station in California. Lightcurve analysis gave a
rotation period of 15.82 hours with a brightness amplitude of 0.20
magnitude ().
Diameter and albedo According to the surveys carried out by the Japanese
Akari satellite, the
NEOWISE mission of NASA's
Wide-field Infrared Survey Explorer, and the Infrared Astronomical Satellite
IRAS,
Prothoon measures between 62.41 and 64.31 kilometers in diameter and its surface has an
albedo between 0.039 and 0.052. The
Collaborative Asteroid Lightcurve Link derives an albedo of 0.0467 and a diameter of 64.41 kilometers based on an
absolute magnitude of 9.9. == Naming ==