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http://hdl.handle.net/20.500.12386/25953
Title: | Global variations in regolith properties on asteroid Vesta from Dawn's low-altitude mapping orbit | Authors: | Denevi, Brett W. Beck, Andrew W. Coman, Ecaterina I. Thomson, Bradley J. AMMANNITO, ELEONORA Blewett, David T. Sunshine, Jessica M. DE SANCTIS, MARIA CRISTINA Li, Jian-Yang Marchi, Simone Mittlefehldt, David W. Petro, Noah E. Raymond, Carol A. Russell, Christopher T. |
Issue Date: | 2016 | Journal: | METEORITICS & PLANETARY SCIENCE | Number: | 51 | Issue: | 12 | First Page: | 2366 | Abstract: | We investigate the depth, variability, and history of regolith on asteroid Vesta using data from the Dawn spacecraft. High-resolution (15-20 m pixel<SUP>-1</SUP>) Framing Camera images are used to assess the presence of morphologic indicators of a shallow regolith, including the presence of blocks in crater ejecta, spur-and-gully-type features in crater walls, and the retention of small (<300 m) impact craters. Such features reveal that the broad, regional heterogeneities observed on Vesta in terms of albedo and surface composition extend to the physical properties of the upper 1 km of the surface. Regions of thin regolith are found within the Rheasilvia basin and at equatorial latitudes from 0-90°E and 260-360°E. Craters in these areas that appear to excavate material from beneath the regolith have more diogenitic (Rheasilvia, 0-90°E) and cumulate eucrite (260-360°E) compositions. A region of especially thick regolith, where depths generally exceed 1 km, is found from 100-240°E and corresponds to heavily cratered, low-albedo surface with a basaltic eucrite composition enriched in carbonaceous chondrite material. The presence of a thick regolith in this area supports the idea that this is an ancient terrain that has accumulated a larger component of exogenic debris. We find evidence for the gardening of crater ejecta toward more howarditic compositions, consistent with regolith mixing being the dominant form of "weathering" on Vesta. | URI: | http://hdl.handle.net/20.500.12386/25953 | URL: | https://onlinelibrary.wiley.com/doi/full/10.1111/maps.12729 | ISSN: | 1086-9379 | DOI: | 10.1111/maps.12729 | Bibcode ADS: | 2016M&PS...51.2366D | Fulltext: | reserved |
Appears in Collections: | 1.01 Articoli in rivista |
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