THE SIZE DISTRIBUTION OF KUIPER BELT OBJECTS FORD≳ 10 km

Abstract
We have performed a survey of the Kuiper belt covering ~1/3 deg2 of the sky using Suprime-cam on the Subaru telescope, to a limiting magnitude of m 50(R) ~ 26.8 and have found 36 new Kuiper belt objects (KBOs). We have confirmed that the luminosity function (LF) of the Kuiper belt must break as previously observed. From the LF, we have inferred the underlying size distribution and find that it is consistent with a large object power-law slope q 1 ~ 4.8 that breaks to a slope q 2 ~ 1.9 at object diameter Db ~ 60 km assuming 6% albedos. We have found no conclusive evidence that the size distribution of KBOs with inclinations i < 5 is different than that of those with i > 5. We discuss implications of this measurement for early accretion in the outer solar system and Neptune migration scenarios.