The Size Distribution of Kuiper belt objects for D> 10 km

TL;DR

This study surveyed Kuiper belt objects to determine their size distribution, confirming a break in the luminosity function and inferring a size distribution with a steep slope for large objects and a shallower slope for smaller ones.

Contribution

It provides the first detailed measurement of the Kuiper belt size distribution for objects larger than 10 km, including a break point at around 60 km diameter.

Findings

Luminosity function of KBOs shows a break at magnitude ~26.8.

Size distribution slope for large objects is approximately 4.8.

Size distribution slope for smaller objects is approximately 1.9.

Abstract

We have performed a survey of the Kuiper belt covering ~ 1/3 a square degree of the sky using Suprime-cam on the Subaru telescope, to a limiting magnitude of m(R)~ 26.8 (50% threshold) and have found 36 new KBOs. We have confirmed that the luminosity function of the Kuiper belt must break as previously observed (Bernstein et al. 2004; Fuentes & Holman 2008). From the luminosity function, we have inferred the underlying size distribution and find that it is consistent with a large object power-law slope q1~4.8 that breaks to a slope q2~1.9 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.