4 Vesta in Color: Lithologic heterogeneity from Dawn Framing Camera Images
Abstract
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 on July 16, 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. We present results from the Dawn FC color observations of 4 Vesta obtained during Survey and HAMO orbit. Our aim is to describe and explain the surface compositional diversity of 4 Vesta and the processes acting on it, in the context of its geology and at high spatial resolution. Mineral characterization will come from an integration of FC data with VIR spectroscopy. Issues to be addressed include: a) what are the distinct color units on Vesta and how do these color variations relate to large-scale geologic features of the surface? b) can known HED meteorites serve as a ground truth for some identified color units? c) what new or different lithologies not present in the terrestrial meteorite collections might occur on Vesta and what is their geologic context? d) do color differences on local scale exist and are these ones correlated with geologic features? In order to extract the maximum information we will apply a variety of analysis tools to the initial Dawn multicolor data. These include standard imaging processing procedures (PCA, mixing analyses, etc.) as well as evaluation and manipulation of color ratios and spectral parameters that are linked to mineralogy (HED components, etc.) and/or surface processes (space weathering, texture, etc.). We intend to also evaluate software tools such as "DawnKey", an automated lithology identification software that allows us to identify spectrally distinct units by using a HED and non-HED spectral library, and an Automated Spectral System Analyzer, a terrain mapping system based on pyroxene mineral chemistry, developed at MPS, to refine mapping approaches and integrate them with mineralogical analyses from Dawn VIR spectroscopic data.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2011
- Bibcode:
- 2011AGUFM.U22A..01N
- Keywords:
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- 6045 PLANETARY SCIENCES: COMETS AND SMALL BODIES / Physics and chemistry of materials;
- 6055 PLANETARY SCIENCES: COMETS AND SMALL BODIES / Surfaces;
- 6205 PLANETARY SCIENCES: SOLAR SYSTEM OBJECTS / Asteroids