科研之友
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摘要
Via joint analysis of a calibrated telescopic survey, which found scattering Kuiper Belt objects, and models of their expected orbital distribution, we explore the scattering-object (SO) size distribution. Although for D %26gt; 100 km the number of objects quickly rise as diameters decrease, we find a relative lack of smaller objects, ruling out a single power law at greater than 99% confidence. After studying traditional %26quot;knees%26quot; in the size distribution, we explore other formulations and find that, surprisingly, our analysis is consistent with a very sudden decrease (a divot) in the number distribution as diameters decrease below 100 km, which then rises again as a power law. Motivated by other dynamically hot populations and the Centaurs, we argue for a divot size distribution where the number of smaller objects rises again as expected via collisional equilibrium. Extrapolation yields enough kilometer-scale SOs to supply the nearby Jupiter-family comets. Our interpretation is that this divot feature is a preserved relic of the size distribution made by planetesimal formation, now %26quot;frozen in%26quot; to portions of the Kuiper Belt sharing a %26quot;hot%26quot; orbital inclination distribution, explaining several puzzles in Kuiper Belt science. Additionally, we show that to match today%26apos;s SO inclination distribution, the supply source that was scattered outward must have already been vertically heated to the of order 10 degrees.
- 出版日期2013-2-10
- 单位西北大学
