Thermophysical Characteristics of OSIRIS-REx Target Asteroid (101955) Bennu

Abstract

In this work, we investigate the thermophysical properties, including thermal inertia, roughness fraction and surface grain size of OSIRIS-REx target asteroid (101955) Bennu by using a thermophysical model with the recently updated 3D radar-derived shape model (\cite[Nolan et al., 2013]{Nolan2013}) and mid-infrared observations (\cite[M$\ddot{u}$ller et al, 2012]{Muller2012}, \cite[Emery et al., 2014]{Emery2014}). We find that the asteroid bears an effective diameter of $510_{-40}^{+6}$ m, a geometric albedo of $0.047_{-0.0011}^{+0.0083}$, a roughness fraction of $0.04_{-0.04}^{+0.26}$, and thermal inertia of $240_{-60}^{+440}\mathrm{J}{\mathrm{m}}^{-2}{\mathrm{s}}^{-0.5}{\mathrm{K}}^{-1}$ for our best-fit solution. The best-estimate thermal inertia suggests that fine-grained regolith may cover a large portion of Bennu's surface, where a grain size may vary from $1.3$ to $31$~mm. Our outcome suggests that Bennu is suitable for the OSIRIS-REx mission to return samples to Earth.

3 pages, 1 figures, accepted to IAU Symposium 318: Asteroids: New Observations, New Models

References in corpus (4)

• Orbit and Bulk Density of the OSIRIS-REx Target Asteroid (101955) Bennu
• Long-term impact risk for (101955) 1999 RQ36
• Shape, Thermal and Surface Properties determination of a Candidate Spacecraft Target Asteroid (175706) 1996 FG3
• Surface Thermophysical Properties determination of OSIRIS-REx target asteroid (101955) Bennu