Geologic mapping of the AV-15 Rheasiliva quadrangle of asteroid 4 Vesta

• Main Authors: White, Oliver L., Yingst, R. Aileen, Berman, D., Frigen, A., Jaumann, R., Le Corre, L., Mest, S., Pieters, C., Preusker, Frank, Raymond, C.A., Reddy, V., Roatsch, Thomas, Russell, C.T., Schenk, P. M., Schmedemann, Nico, DAWN, Science Team
• Format: Conference Object
• Language: English
• Published: 2012
• Subjects: Planetengeologie; South pole
• Online Access: https://elib.dlr.de/76085/; https://elib.dlr.de/76085/1/1264.pdf

NASA’s Dawn spacecraft entered orbit of the inner main belt asteroid 4 Vesta on July 16, 2011, and is spending one year in orbit to characterize the geology, elemental and mineralogical composition, topography, shape, and internal structure of Vesta be-fore departing to asteroid 1 Ceres in late 2012. As part of the Dawn data analysis the Science Team is con-ducting geologic mapping of the surface, in the form of 15 quadrangle maps. This abstract reports results from the mapping of quadrangle Av-15, named Rheasilvia. Data: The base for mapping this quadrangle is a monochrome Framing Camera (FC) mosaic produced from the High Altitude Mapping Orbit (HAMO) data with a spatial resolution of ~70 m/pixel. This base is supplemented by a Digital Terrain Model (DTM) de-rived from Survey orbit data (Figure 1). Also used to support the mapping are FC color ratio images from the Survey orbit with a spatial resolution of ~250 m/pixel, slope and contour maps derived from the DTM, and Visible and InfraRed (VIR) hyperspectral images from the Survey and HAMO orbits with spatial resolutions of 700 and 200 m/pixel, respectively. Geologic Setting: Av-15 Rheasilvia Quadrangle covers the southern pole of Vesta and stretches north to 21°S. This quadrangle is dominated by the central mound complex of the Rheasilvia impact basin. The quad is heterogeneous spectrally, and in terms of color and albedo [1-4]; these heterogeneities were originally interpreted to stem from extrusive volcanic activity and impact. Imaging by the Hubble Space Telescope (HST) in 1994 and 1996 revealed a crater at the south pole that excavated ~1% of the asteroid's volume; the presence of a 1-μm absorption feature was interpreted as coarse-grained plutonic pyroxene or pos-sibly olivine in a differentiated upper mantle [5].