Abstract
We present observations of thermal emission from fifteen transneptunian objects (TNOs) made using the Spitzer-Space Telescope. Thirteen of the targets are members of the Classical Population: six dynamically hot Classicals, five dynamically cold Classicals, and two dynamically cold inner Classical Kuiper belt objects (KBOs). We fit out observations using thermal models to determine the sizes and albedos Of Our targets finding that the cold Classical KBOs have distinctly higher Visual albedos than the hot Classicals and other TNO dynamical classes. The cold Classicals Ire known to be distinct from other TNOs in terms of their Color distribution, size distribution, and binarity fraction. The Classical objects in our sample all have Fed colors yet they show a diversity of albedos which suggests that there is not a simple relationship between albedo and color. As a consequence of high albedos, the mass estimate of the cold Classical Kuiper belt is reduced from approximately 0.01 M-circle plus to approximately 0.001 M-circle plus. Our results also increase significantly the sample of small Classical KBOs with known albedos and sizes from 21 to 32 Such objects. (c) 2009 Elsevier Inc. All rights reserved,