Phase curve and albedo of asteroid 5535 Annefrank

Seventy‐two images of the S‐class asteroid 5535 Annefrank, acquired on 2 November 2002 at target ranges of 11,415–3078.5 km, were transmitted to Earth as a part of an engineering readiness test of the Stardust mission. Forty‐four of these were used to create a phase curve extending to 134°, the largest angle yet achieved for any S‐class asteroid. Flux fell by more than six magnitudes between the extrapolated 0° and 134°. A maximum illuminated cross section of 16 km2 was seen at a phase angle of 47.2°. Assuming a camera efficiency of 75%, a broadband (470–940 nm) geometric albedo of 0.24 was derived for Annefrank.