Its images show the asteroid to be 6.6 × 5.0 × 3.4 km, twice as big as previously thought, and its main body shaped like a triangular prism with several visible impact craters.

[8] Preliminary analysis of the Stardust imagery suggests that Annefrank may be a contact binary, although other possible explanations exist for its observed shape.

[3][5] In January 2014, photometric observations at the Palomar Transient Factory gave a rotation period of 15.156 and 21.33 hours with an amplitude of 0.17 and 0.20 magnitude, respectively (U=2/2).

[6][7] The lightcurve data suggests that Annefrank is not Lambertian, meaning that surface features, such as shadows from boulders and craters, play a role in the object's perceived brightness and not just the asteroid's relative size when seen from that orientation.

[8] This minor planet was named after Anne Frank, the German-Dutch-Jewish diarist who died in a Nazi concentration camp during the Second World War.