Impact Craters on Pluto and Charon Indicate a Deficit of Small Kuiper Belt Objects

TL;DR

The study uses high-resolution images from the New Horizons flyby to analyze impact craters on Pluto and Charon, revealing a significant deficit of small Kuiper Belt Objects, which informs our understanding of the early Solar System's small body population.

Contribution

This paper presents evidence of a deficit of small Kuiper Belt Objects based on crater analysis, providing new insights into the size distribution of KBOs in the early Solar System.

Findings

Fewer small craters than expected suggest a scarcity of small KBOs.

Some surface areas are over 4 billion years old, preserving ancient crater records.

The crater size distribution indicates a different population of small bodies than previously assumed.

Abstract

The flyby of Pluto and Charon by the New Horizons spacecraft provided high-resolution images of cratered surfaces embedded in the Kuiper belt, an extensive region of bodies orbiting beyond Neptune. Impact craters on Pluto and Charon were formed by collisions with other Kuiper belt objects (KBOs) with diameters from ~40 kilometers to ~300 meters, smaller than most KBOs observed directly by telescopes. We find a relative paucity of small craters less than approximately 13 kilometers in diameter, which cannot be explained solely by geological resurfacing. This implies a deficit of small KBOs (less than 1 to 2 kilometers in diameter). Some surfaces on Pluto and Charon are likely greater than 4 billion years old, thus their crater records provide information on the size-frequency distribution of KBOs in the early Solar System.