Correlating Arecibo Radar and IRTF Near-Infrared Spectral Observations of 105 Artemis
Abstract
We have coordinated radar observations with spectral observations of 105 Artemis, a low-albedo main-belt asteroid. Previous spectra indicate that 105 Artemis is a C-type asteroid with hydrated minerals on the surface at some rotational phases but not at others. Serendipitous radar observations showed radar albedo changes which seem to suggest that the hydrated areas have higher radar albedo than anhydrous areas. The near-infrared spectra from 0.8--4.1 microns obtained at the IRTF on 6 March 2006 indicate a combined water/OH absorption band with average depth of 89 +/0.03 percent due to hydrated silicates on the surface.The radar images of 105 Artemis are remarkably complex, showing bright glints and irregular features that may be linked to the reflectivity of the surface, and therefore the composition instead of the shape of the asteroid. In order to link the observations together, the amateur astronomy community has helped observe the lightcurve. The rotation period of 105 Artemis is 37.18 +/0.02 hours, substantially longer than the previous estimate of 16.8 hours. Using this rotation period, we link the spectra and radar observations together, which were made 6 weeks apart. The viewing geometry can be determined for the radar images using the rotation period and observed frequency bandwidth. A simple elliptical model has been developed to describe the areas of 105 Artemis that have been observed. Results of these combined observations will be presented.
- Publication:
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American Astronomical Society Meeting Abstracts
- Pub Date:
- December 2006
- Bibcode:
- 2006AAS...209.2504H