Asteroid (101955) 1999 RQ36: Spectroscopy from 0.4 to 2.5 microns and Meteorite Analogs
Abstract
We present reflectance spectra from 0.4 to 2.5 microns of asteroid (101955) 1999 RQ36, the target of the proposed OSIRIS-REx spacecraft mission. The visible spectral data were obtained at the McDonald Observatory 2.1-m telescope with the ES2 spectrograph. The infrared spectral data were obtained at the NASA Infrared Telescope Facility using the SpeX instrument. The average visible spectrum is combined with the average near-infrared wavelength spectrum to form a composite spectrum. We use three methods to constrain the compositional information in the composite spectrum of asteroid (101955) 1999 RQ36 (hereafter RQ36). First, we perform a least-squares search for meteorite spectral analogs using 15,000 spectra from the RELAB database. Three most likely meteorite analogs are proposed based on the least-squares search. Next, six spectral parameters are measured for RQ36 and their values are compared with the ranges in parameter values established by sets of RELAB spectra representing relevant spectrally measured meteorite classes. A most likely meteorite analog group is proposed based on the depth of overlap in parameter values. The results of the least-squares search and the parametric comparisons point to CIs and/or CMs as the most likely meteorite analogs for RQ36, and CKs and ureilites as the least likely. We speculate that RQ36 is composed of a CM1-like material. Finally, RQ36 is compared to other B-type asteroids measured by Clark et al. (2010 JGR 15) and is found to be most consistent with the Themis Group B-types. This is particularly interesting because asteroid 24 Themis was recently discovered to have H2O ice on the surface (Rivkin and Emery 2010, Nature 464; Campins et al. 2010, Nature 464).
- Publication:
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AAS/Division for Planetary Sciences Meeting Abstracts #42
- Pub Date:
- October 2010
- Bibcode:
- 2010DPS....42.6006C