Colors of Vesta from Dawn Survey Orbit: Surface mineralogical perspecitve

Kurzfassung

4 Vesta is the largest differentiated asteroid that is still mostly intact today and is considered to be a model for the initial stages of planetary differentiation. NASA’s Dawn mission entered orbit around Vesta in July 2011 for a yearlong global characterization. The Framing Cameras (FC) onboard the Dawn spacecraft will image the asteroid in one clear and seven narrow band filters covering the wavelength range between 0.4-1.0 μm and the Visual and Infrared Mapping Spectrometer (VIR) will map the spectroscopic properties from the visible to 5 µm. The Framing Cameras have been developed and built under the leadership of the Max Planck Institute for Solar System Research, Germany, with significant contributions by DLR Institute of Planetary Research, Berlin, and in coordination with IDA, Braunschweig. We present the first results largely from the Dawn FC color observations of 4 Vesta obtained during the Approach and Survey phases, which will be completed by August 2011. Our aim is to address some basic questions related to Vesta’s surface compositional diversity and the processes acting on it, in the context of its geology, for example, a) Are large-scale albedo variations on Vesta related to color/compositional units; is the hemispherical dichotomy confirmed? b) What are the distinct color units on Vesta and how do these color variations relate to geologic features of the surface? c) Can known HED meteorites serve as a ground truth for some identified color units? d) What new or different lithologies not present in the terrestrial meteorite collections might occur on Vesta and what is their geologic context? Acknowledgement: The authors acknowledge the support of the Dawn Science, Instrument and Operations Teams