In order to complement the ExploreNEOs program, we are characterizing surface compositions of near-Earth objects (NEOs) with near-infrared (NIR) spectroscopy (0.7 to 2.5 microns). The core ExploreNEOs program is an ambitious exploration of the history of near-Earth space using NASA's Spitzer space telescope. Currently in the middle of its two-year timeline, that ongoing project will ultimately observe 700 NEOs using the Infrared Array Camera (IRAC) in two photometric bands (3.6 and 4.5 microns). The proposed goals of the ExploreNEOs survey are to measure the size distribution of NEO population; to measure the fraction of NEOs likely to be dead comet nuclei, with implications for the flux of organic material onto the Earth; to measure the albedo distribution of NEOs; and to study properties of individual NEOs, including their thermal properties and densities, and detailed properties of a subset of "ground-truth" objects. Whereas the Spitzer photometry will provide accurate estimates of size and albedo for most targets, albedo is only a general indicator of potential composition. NIR spectroscopy complements the Spitzer results by enabling direct determination of surface compositions. The NIR measurements thereby contribute to the overall goals of the ExploreNEOs program by allowing the team to assess the mix of mineralogies among NEOs and to infer the contributions from dead comets to the NEO population. NASA's Infrared Telescope Facility (IRTF) is the main observatory used for the NIR spectral measurements. Of the ˜700 Spitzer targets, 127 are viewable and bright enough for spectroscopy with the IRTF. Thus far, we have obtained NIR spectra of 42 of the ExploreNEO targets. We will present these data along with compositional analysis.
|Journal||Bulletin of the American Astronomical Society|
|Publication status||Published - 1-Oct-2010|
|Event||42nd DPS meeting of the American Astronomical Society, 2010 - Pasadena, California, United States|
Duration: 4-Oct-2010 → 7-Oct-2010