MID-INFRARED PHOTOMETRIC ANALYSIS OF MAIN BELT ASTEROIDS: A TECHNIQUE FOR COLOR-COLOR DIFFERENTIATION FROM BACKGROUND ASTROPHYSICAL SOURCES
- NASA Herschel Science Center, California Institute of Technology, MC 100-22, Pasadena, CA 91125 (United States)
- Spitzer Science Center, California Institute of Technology, Pasadena, CA 91125 (United States)
- Department of Physics and Astronomy, Pomona College, Claremont, CA 91711 (United States)
- Department of Astronomy, University of Washington, Seattle, WA 98195 (United States)
- Department of Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States)
- Service d'Astrophysique, CEA/Saclay, Gif-sur-Yvette (France)
- NRAO, NRAO, Green Bank, WV 24944 (United States)
- Institute for Astronomy, University of Hawaii, Honolulu, HI 96822 (United States)
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States)
- Department of Physics, Harvey Mudd College, Claremont, CA 91711 (United States)
- Stratospheric Observatory for Infrared Astronomy, Universities Space Research Association, NASA Ames Research Center, Mail Stop 211-3, Moffett Field, CA 94035 (United States)
The Spitzer Space Telescope routinely detects asteroids in astrophysical observations near the ecliptic plane. For the galactic or extragalactic astronomer, these solar system bodies can introduce appreciable uncertainty into the source identification process. We discuss an infrared color discrimination tool that may be used to distinguish between solar system objects and extrasolar sources. We employ four Spitzer Legacy data sets, the First Look Survey-Ecliptic Plane Component (FLS-EPC), SCOSMOS, SWIRE, and GOODS. We use the Standard Thermal Model to derive FLS-EPC main belt asteroid (MBA) diameters of 1-4 km for the numbered asteroids in our sample and note that several of our solar system sources may have fainter absolute magnitude values than previously thought. A number of the MBAs are detected at flux densities as low as a few tens of {mu}Jy at 3.6 {mu}m. As the FLS-EPC provides the only 3.6-24.0 {mu}m observations of individual asteroids to date, we are able to use this data set to carry out a detailed study of asteroid color in comparison to astrophysical sources observed by SCOSMOS, SWIRE, and GOODS. Both SCOSMOS and SWIRE have identified a significant number of asteroids in their data, and we investigate the effectiveness of using relative color to distinguish between asteroids and background objects. We find a notable difference in color in the IRAC 3.6-8.0 mm and MIPS 24 {mu}m bands between the majority of MBAs, stars, galaxies, and active galactic nuclei, though this variation is less significant when comparing fluxes in individual bands. We find median colors for the FLS-EPC asteroids to be [F(5.8/3.6), F(8.0/4.5), F(24/8)] = (4.9 {+-} 1.8, 8.9 {+-} 7.4, 6.4 {+-} 2.3). Finally, we consider the utility of this technique for other mid-infrared observations that are sensitive to near-Earth objects, MBAs, and trans-Neptunian objects. We consider the potential of using color to differentiate between solar system and background sources for several space-based observatories, including Warm Spitzer, Herschel, and WISE.
- OSTI ID:
- 21460142
- Journal Information:
- Astrophysical Journal, Vol. 720, Issue 1; Other Information: DOI: 10.1088/0004-637X/720/1/114; ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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