NOAO >   Observing Info >   Approved Programs >   2008A-0469

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Proposal Information for 2008A-0469


PI: Andrew Rivkin, Johns Hopkins University/Applied Physics Laboratory, andy.rivkin@jhuapl.edu
Address: 11100 Johns Hopkins Rd., Laurel, MD 20723, USA

CoI: David Trilling, University of Arizona
CoI: Peter Allen, Penn State University

Title: Small Koronis-Family Asteroids as a Probe of Space Weathering

Abstract: Spectra of the most common meteorites are not good matches to the most common asteroids found in the meteorite source regions of the main asteroid belt. This mismatch has been (controversially) attributed to alteration of asteroid regolith by micrometeorites and solar wind, through processes dubbed \it space weathering. Recent evidence supports the models of space weathering on asteroid surfaces, and suggests that the 1-5 km diameter range is a critical transition size. However, this recent work has focused on near-Earth asteroids of the S spectral class, a sample which may not be homogeneous in composition and is potentially in a space environment quite different from the main belt. In order to make an apples-to-apples comparison, we propose to measure the visible colors of roughly 100 Koronis-family members to spectrally characterize objects of this transition size. Revealing fresh surfaces on main-belt asteroids would solve a decades-long mystery by demonstrating a direct link between the most common meteorites (80% of all meteorites measured in the laboratory display the characteristics of fresh surfaces) and the main asteroid belt.


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