ExploreNEOs. III. Physical characterization of 65 potential spacecraft target asteroids

Mueller, Michael and Delbo', M. and Hora, J. L. and Trilling, D. E. and Bhattacharya, B. and Bottke, W. F. and Chesley, S. and Emery, J. P. and Fazio, G. and Harris, A. W. and Mainzer, A. and Mommert, M. and Penprase, B. and Smith, H. A. and Spahr, T. B. and Stansberry, J. A. and Thomas, C. A. (2011) ExploreNEOs. III. Physical characterization of 65 potential spacecraft target asteroids. Astronomical Journal, 141 (4). ISSN 1538-3881

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Abstract

Space missions to near-Earth objects (NEOs) are being planned at all major space agencies, and recently a manned mission to an NEO was announced as a NASA goal. Efforts to find and select suitable targets (plus backup targets) are severely hampered by our lack of knowledge of the physical properties of dynamically favorable NEOs. In particular, current mission scenarios tend to favor primitive low-albedo objects. For the vast majority of NEOs, the albedo is unknown. Here we report new constraints on the size and albedo of 65 NEOs with rendezvous Delta nu < 7 km s(-1). Our results are based on thermal-IR flux data obtained in the framework of our ongoing (2009-2011) ExploreNEOs survey using NASA's "Warm-Spitzer" space telescope. As of 2010 July 14, we have results for 293 objects in hand (including the 65 low-Delta nu NEOs presented here); before the end of 2011, we expect to have measured the size and albedo of similar to 700 NEOs (including probably similar to 160 low-Delta nu NEOs). While there are reasons to believe that primitive volatile-rich materials are universally low in albedo, the converse need not be true: the orbital evolution of some dark objects likely has caused them to lose their volatiles by coming too close to the Sun. For all our targets, we give the closest perihelion distance they are likely to have reached (using orbital integrations from Marchi et al. 2009) and corresponding upper limits on the past surface temperature. Low-Delta nu objects for which both albedo and thermal history may suggest a primitive composition include (162998) 2001 SK162, (68372) 2001 PM9, and (100085) 1992 UY4.

Item Type:	Article
Publisher’s Statement:	© 2011 The American Astronomical Society. Published by IOP Publishing.
ID number or DOI:	10.1088/0004-6256/141/4/109
Keywords:	10302 1989 ml; albedos; diameters; infrared: planetary systems; magnitude; minor planets, asteroids: general; mission; near-Earth asteroids; object survey; Photometry; radiation mechanisms: thermal; space vehicles; spectral properties; Surveys; telescope
Subjects:	Q Science > QB Astronomy
NAU Depositing Author Academic Status:	Faculty/Staff
Department/Unit:	College of Engineering, Forestry, and Natural Science > Physics and Astronomy
Date Deposited:	30 Sep 2015 16:43
URI:	http://openknowledge.nau.edu/id/eprint/375

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