T239 Dawn at Vesta: Initial Results from the Survey Orbit

Wednesday, 12 October 2011
8:00 AM - 12:00 PM
Room L100H-J

4 VESTA MINERALOGY: SUGGESTIONS FROM VIR OBSERVATIONS

Paper number: T239-5
Program: Technical Sessions
Time: 9:15 AM – 9:30 AM

Authors

Abstract

We present a preliminary analysis of data acquired by the Visual and InfraRed Spectrometer (VIR) to map Vesta’s mineralogy. VIR is the Dawn’s instrument devoted to the study of the mineralogical composition and thermophysical properties of Vesta. The instrument performs imaging spectroscopy in the overall range from the near-UV through the near IR (0.25-5 microns) and has moderate to high spectral resolution combined with imaging capabilities. Surface composition can be addressed by visual and infrared spectral features. Moreover, the ability to map the existence and intensity of such features will enable discrimination of compositional classes across the surface.

One of the main goals of Dawn is to determine the mineral composition of the surface and to place it in a geologic context. Several diagnostic absorption bands of key minerals occur in the visible and near-infrared regions. VIS and Near-IR spectroscopy contribute to asteroid studies by delineating absorption features that are not resolved with broad-band filters and by refining the evaluation of differences in terms of spectral shape and band depth and width. Maps of the current surface mineralogy will ultimately lead to the understanding of the surface evolution and determination of the processes affecting it.

Our present understanding of Vesta is based on telescopic remote sensing and the analysis of the HED meteorites, which are thought to be representative of Vesta as a whole. VIR data of materials exposed on the asteroid’s surface provide new insights into the processes that produced the solar system’s largest differentiated asteroid.