Constraining the physical properties of near-Earth object 2009 Bd

Mommert, M. and Hora, J. L. and Farnocchia, D. and Chesley, S. R. and Vokrouhlický, D. and Trilling, D. E. and Mueller, M. and Harris, A. W. and Smith, H. A. and Fazio, G. G. (2014) Constraining the physical properties of near-Earth object 2009 Bd. Astrophysical Journal, 786 (2). pp. 148-156. ISSN 1538-4357

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Abstract

We report on Spitzer Space Telescope Infrared Array Camera observations of near-Earth object 2009 BD that were carried out in support of the NASA Asteroid Robotic Retrieval Mission concept. We did not detect 2009 BD in 25 hr of integration at 4.5 μm. Based on an upper-limit flux density determination from our data, we present a probabilistic derivation of the physical properties of this object. The analysis is based on the combination of a thermophysical model with an orbital model accounting for the non-gravitational forces acting upon the body. We find two physically possible solutions. The first solution shows 2009 BD as a 2.9 ± 0.3 m diameter rocky body (ρ = 2.9 ± 0.5 g cm–3) with an extremely high albedo of that is covered with regolith-like material, causing it to exhibit a low thermal inertia ( SI units). The second solution suggests 2009 BD to be a 4 ± 1 m diameter asteroid with that consists of a collection of individual bare rock slabs (Γ = 2000 ± 1000 SI units, g cm–3). We are unable to rule out either solution based on physical reasoning. 2009 BD is the smallest asteroid for which physical properties have been constrained, in this case using an indirect method and based on a detection limit, providing unique information on the physical properties of objects in the size range smaller than 10 m.

Item Type:	Article
Publisher’s Statement:	© 2014 The American Astronomical Society. Published by IOP Publishing.
ID number or DOI:	10.1088/0004-637X/786/2/148
Keywords:	asteroidal fragments; Asteroids; Astrophysics; hayabusa; infrared: planetary systems; minor planets, asteroids: individual (2009 BD); mission; near-Earth objects; population; probability theory; radar; radiation pressure; spitzer-space-telescope; SPITZER Space Telescope (Spacecraft); target; thermal-infrared observations; The Solar System; yarkovsky
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 17:37
URI:	http://openknowledge.nau.edu/id/eprint/412

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