A Search for Slow-Moving Objects and the Luminosity Function of the Kuiper Belt

Abstract

We describe the detection of two slow-moving objects in a survey covering 0.7° sq. of the ecliptic to a limiting magnitude m<SUB>R</SUB>=23.S. The objects are probable members of the Kuiper belt. Assuming that they travel in circular orbits and have geometric albedo 0.03, their heliocentric distances are 43.4 and 35.2 AU and their radii are 150 and 125 km, respectively. Existing surveys for slow-moving objects, combined with the plausible assumption that the Kuiper belt is the source of Jupiter-family comets, constrain the Kuiper belt luminosity function N( &lt;H), where H is the absolute magnitude. The slope p ≡ d log<SUB>10</SUB> N/dH is near 0.1 at H<SUB>R</SUB>≃9, which is shallower than for asteroids or comets. There is evidence for a bright-end cutoff near H<SUB>R</SUB>≃7 and the slope also appears to steepen for H<SUB>R</SUB>≳12.