Infrared Colors of Small Serendipitously-Found Asteroids in the UKIRT Hemisphere Survey

TL;DR

This study utilizes the UKIRT Hemisphere Survey to analyze infrared colors of small asteroids, revealing size-related surface color variations and demonstrating a new pipeline for asteroid detection in survey data.

Contribution

A novel pipeline for recovering and analyzing small asteroids in infrared survey data, extending detection depth beyond previous surveys like 2MASS.

Findings

Small inner main belt asteroids are less red than larger ones.

Small middle and outer belt asteroids are redder than larger counterparts.

Survey extends about two magnitudes deeper than 2MASS.

Abstract

The UKIRT Hemisphere Survey covers the northern sky in the infrared from 0-60 degrees declination. Current data releases include both J and K bands, with H-band data forthcoming. Here we present a novel pipeline to recover asteroids from this survey data. We recover 26,138 reliable observations, corresponding to 23,399 unique asteroids, from these public data. We measure J-K colors for 601 asteroids. Our survey extends about two magnitudes deeper than 2MASS. We find that our small inner main belt objects are less red than larger inner belt objects, perhaps because smaller asteroids are collisionally younger, with surfaces that have been less affected by space weathering. In the middle and outer main belt, we find our small asteroids to be redder than larger objects in their same orbits, possibly due to observational bias or a disproportionate population of very red objects among these smaller asteroids. Future work on this project includes extracting moving object measurements from H and Y band data when it becomes available.