Taxonomic Classification of Asteroids via Broadband Near-Infrared Photometry

For faint asteroids, it is not practical to obtain near-infrared spectra. However, it may be possible to use broadband photometry to infer spectral classifications and study composition. As a test of this, we processed SpeX near-infrared asteroid spectral data to simulate colors that would be obtained through photometry. We have found that certain color combinations (for example, z-J and H-K) can prove diagnostic in asteroid spectral classification. To this end, we have defined certain color-color regions that make it possible to define an asteroid as being a likely candidate for a certain spectral type. The regions identified define V and D type asteroids, the S-Q group, and the C-X group. Knowledge and use of these regions will significantly increase the usefulness of NIR broadband photometry in the study of near earth objects and allow characterization of asteroids that are too faint to be observed spectroscopically. Work on this project is made possible through the NSF REU program at Northern Arizona University and by funding from the Spitzer Space Telescope/JPL/Caltech.