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Spitzer IRS (8-30 micron) Spectra of Basaltic Asteroids 1459 Magnya and 956 Elisa: Mineralogy and Thermal PropertiesWe report preliminary results from Spitzer IRS (Infrared Spectrograph) spectroscopy of 956 Elisa, 1459 Magnya, and other small basaltic asteroids with the Spitzer IRS. Program targets include members of the dynamical family of the unique large differentiated asteroid 4 Vesta ("Vestoids"), several outer-main-belt basaltic asteroids whose orbits exclude them from originating on 4 Vesta, and the basaltic near-Earth asteroid 4055 Magellan. The preliminary thermal model (STM) fit to the 5--35 micron spectrum of 956 Elisa gives a radius of 5.4 +/- 0.3 km and a subsolar- point temperature of 282.2 +/- 0.5 K. This temperature corresponds to eta approximately equals 1.06 +/- 0.02, which is substantially higher than the eta approximately equals 0.756 characteristic of large main-belt asteroids. Unlike 4 Vesta and other large asteroids, therefore, 956 Elisa has significant thermal inertia in its surface layer. The wavelength of the Christiansen feature (emissivity maximum near 9 micron), the positions and shapes of the narrow maxima (10 micron, 11 micron) within the broad 9--14 micron silicate band, and the 19--20 micron minimum are consistent with features found in the laboratory spectra of diogenites and of low-Ca pyroxenes of similar composition (Wo<5, En50-En75).
Document ID
20090038181
Document Type
Conference Paper
Authors
Lim, Lucy F. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Emery, J. P. (Tennessee Univ. TN, United States)
Moskovitz, N. A. (Hawaii Univ. HI, United States)
Date Acquired
August 24, 2013
Publication Date
October 4, 2009
Subject Category
Lunar and Planetary Science and Exploration
Meeting Information
11226-10-ST 41st annual meeting of the Division for Planetary Sciences (DPS) of the American Astronomical Society(Fajardo)
Distribution Limits
Public
Copyright
Other