Near-Infrared Spectrophotometry of Phobos and Deimos
โ Scribed by A.S. Rivkin; R.H. Brown; D.E. Trilling; J.F. Bell III; J.H. Plassmann
- Publisher
- Elsevier Science
- Year
- 2002
- Tongue
- English
- Weight
- 308 KB
- Volume
- 156
- Category
- Article
- ISSN
- 0019-1035
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โฆ Synopsis
We have observed the leading and trailing hemispheres of Phobos from 1.65 to 3.5 ยตm and Deimos from 1.65 to 3.12 ยตm near opposition. We find the trailing hemisphere of Phobos to be brighter than its leading hemisphere by 0.24 ยฑ 0.06 magnitude at 1.65 ยตm and brighter than Deimos by 0.98 ยฑ 0.07 magnitude at 1.65 ยตm. We see no difference larger than observational uncertainties in spectral slope between the leading and trailing hemispheres when the spectra are normalized to 1.65 ยตm. We find no 3-ยตm absorption feature due to hydrated minerals on either hemisphere to a level of โผ5-10% on Phobos and โผ20% on Deimos. When the infrared data are joined to visible and near-IR data obtained by previous workers, our data suggest the leading (Stickney-dominated) side of Phobos is best matched by T-class asteroids. The spectral slope of the trailing side of Phobos and leading side of Deimos are bracketed by the D-class asteroids. The best laboratory spectral matches to these parts of Phobos are mature lunar soils and heated carbonaceous chondrites. The lack of 3-ยตm absorption features on either side of Phobos argues against the presence of a large interior reservoir of water ice according to current models of Phobos' interior (F.
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