Distribution of olivine and pyroxene in S-type asteroids throughout the inner main belt
| Autor: | Storm, Shaye Perry |
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| Jazyk: | angličtina |
| Rok vydání: | 2008 |
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| Druh dokumentu: | Diplomová práce |
| Popis: | Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2008. Cataloged from PDF version of thesis. "May 5, 2008." "This thesis was submitted to the Institute Archives without all the required signatures"--Disclaimer Notice page. Includes bibliographical references (page 33). The mineralogical composition of asteroids can be constrained using visible and near-infrared (VNIR) spectroscopy. The most prominent spectral features observed over this wavelength range are due to olivine and pyroxene, the two most abundant minerals in both chondritic and achondritic meteorites. The observed ratio of these two minerals is highly dependent on the amount of heating that an asteroid has undergone. The 1-micron band center wavelength and the band area ratio (BAR) between the 2- and 1-micron bands reveal relative abundances of olivine and/or pyroxene on an asteroid surface (Gaffey, 1993). A large sample of S-, A-, V-, and R-type asteroid spectra was collected over the visible and near-IR wavelengths during the second phase of the Small Main-belt Asteroid Spectroscopic Survey (Bus and Binzel, 2002) and using the low-resolution SpeX spectrograph (Rayner, 2003) at NASA's Infrared Telescope Facility (IRTF). Here we present a methodology for calculating the location of the 1-micron band center wavelength and BAR with appropriate 1- sigma uncertainties. This method was used to characterize 188 S-type asteroids throughout the inner main belt. We will also present the distribution of olivine / pyroxene throughout the main belt by measuring how the S-type mineralogy varies with heliocentric distance. This will provide a better understanding of both the thermal processing across the main belt and subsequent mixing of asteroids through collisional and dynamical processes. by Shaye Perry Storm. S.B. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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