Vesta, vestoids, and the HED meteorites: Interconnections and differences based on Dawn Framing Camera observations

B. J. Buratti, P. A. Dalba, M. D. Hicks, V. Reddy, M. V. Sykes, T. B. McCord, D. P. O'Brien, C. M. Pieters, T. H. Prettyman, L. A. McFadden, Andreas Nathues, Lucille Le Corre, S. Marchi, Carol Raymond, Chris Russell

Research output: Contribution to journalArticlepeer-review

11 Scopus citations

Abstract

The Framing Camera (FC) on the Dawn spacecraft provided the first view of 4 Vesta at sufficiently high spatial resolution to enable a detailed correlation of the asteroid's spectral properties with geologic features and with the vestoid (V-type) asteroids and the Howardite-Eucrite-Diogenite (HED) class of meteorites, both of which are believed to originate on Vesta. We combine a spectral analysis of the basin with visible and near-IR spectroscopy of vestoids and with archived data over the same spectral range for HED meteorites. The vestoids are only slightly more akin to the Rheasilvia basin than to Vesta as a whole, suggesting that the crustal material ejected is a well-mixed collection of eucritic and diogenitic materials. The basin itself is more diogenitic, implying Vesta is differentiated and the impact that created Rheasilvia uncovered a mineralogically distinct layer. The Rheasilvia basin exhibits a larger range in pyroxene band strengths than Vesta as a whole, further implying that the basin offers a view into a complex, differentiated protoplanet. The discrepancy between the spectral properties of the HED meteorites and Vesta, in particular the meteorites' deeper pyroxene absorption band and the redder color of the vestoids, can be explained by the abundance of smaller particles on Vesta and by the addition of low-albedo exogenous particles to its surface, which in turn are due to its larger gravity and longer exposure time to impact processing. Solar phase effects are slight and do not explain the spectral discrepancies between the HEDs, Vesta, and the vestoids. Key Points Differences in the HEDs, V-types, and Vesta are due mostly to particle size The Rheasilvia basin is the source of most vestoids and HED meteorites The Rheasilvia basin provides a view into a differentiated asteroid

Original languageEnglish (US)
Pages (from-to)1991-2003
Number of pages13
JournalJournal of Geophysical Research: Planets
Volume118
Issue number10
DOIs
StatePublished - Oct 2013
Externally publishedYes

Keywords

  • asteroids
  • HED
  • Vesta
  • vestoids

ASJC Scopus subject areas

  • Geochemistry and Petrology
  • Geophysics
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science

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