The albedo, size, and density of binary kuiper belt object (47171) 1999 TC36

摘要: We measured the system-integrated thermal emission of binary Kuiper Belt object (47171 ) 1999 TC36, at wavelengths near 24 and 70 μm using Spitzer Space Telescope. fit these data visual magnitude both standard model thermophysical models. find that effective diameter is 405 km, with a range 350-470 visible geometric albedo for system 0.079, 0.055-0.11. The orbit, contrast between components, mass have been determined from HSTdata studied by Margot et al. Our diameter, combined mass, indicates an average density objects 0.5 g cm-3, 0.3-0.8 cm -3. This low compared to materials expected be abundant in solid bodies trans-Neptunian region, requiring 50%-75% interior TC36 taken up void space. conclusion not greatly affected if (47171)1999 differentiated (in sense having either rocky or just nonporous core). If primary itself binary, (hypothetical) triple would 0.4-1.l -3, porosity 15%-70%. © 2006. American Astronomical Society. All rights reserved.