Thermal emission spectra of Mars (5. 4-10. 5. mu. m): Evidence for sulfates, carbonates, and hydrates

Conference · Thu Aug 30 00:00:00 EDT 1990 · Journal of Geophysical Research; (United States)

OSTI ID:5384727

Pollack, J B; Roush, T; Witteborn, F; Bregman, J; Wooden, D; Stoker, C; Toon, O B ^[1]; Rank, D ^[2]; Dalton, B ^[3]; Freedman, R ^[4]

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1. NASA Ames Research Center, Moffett Field, CA (USA)
2. Univ. of California, Santa Cruz (USA)
3. Synernet Corporation, Fremont, CA (USA)
4. Sterling Software, Inc., Palo Alto, CA (USA)

The authors have obtained spectra of the thermal emission from Mars in the 5.4-10.5 {mu}m wavelength domain at a resolving power of about 60 from the Kuiper Airborne Observatory. These data, as well as spectral fluxes of single spots based using the star {alpha} Tau as a calibration standard, show a number of emission and absorption features. They are present in sets of spectra taken at two different times. Some of the absorption features are due to gaseous CO{sub 2} in the Martian atmosphere. The remainder of the absorption and emission features are due to minerals present in the airborne dust and on the surface. Comparison of the strength of features seen at similar times, but with three different air masses and ground temperatures, suggests that the emission features arise primarily from surface emissivity spectral variations and that the absorption features arise from components of the atmosphere. Based on comparisons of the observed features with laboratory data for a broad ensemble of minerals, spectra of other solar system bodies, and relevant compositional information about Mars, they have made the following tentative identifications of the observed features. Emission features at 7.8 and 9.7 {mu}m are attributed to surface silicates; an emission feature at 6.1 {mu}m is attributed to a molecular water component of the surface material; an absorption band at 8.7 {mu}m as well as possibly one at 9.8 {mu}m is ascribed to sulfate or bisulfate anions, probably located in a distorted crystalline site; and an absorption band at 6.7 {mu}m is attributed to carbonate or bicarbonate anions located in a distorted crystalline site, although they cannot totally rule out a nitrate origin for this feature. These results imply that minerals formed by weathering processes represent major reservoirs of volatile species on current Mars.

• OSTI ID: 5384727
• Report Number(s): CONF-9001119-; CODEN: JGREA; TRN: 91-023785
• Journal Information: Journal of Geophysical Research; (United States), Vol. 95:B9; Conference: 4. international conference on Mars, Tucson, AZ (United States), 10-13 Jan 1990; ISSN 0148-0227
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
MARS PLANET
EMISSION SPECTRA
ABSORPTION SPECTRA
CARBONATES
CHEMICAL COMPOSITION
DUSTS
HYDRATES
MINERALS
ORIGIN
PLANETARY ATMOSPHERES
PLANETARY EVOLUTION
SULFATES
SURFACES
THERMAL RADIATION
VOLATILE MATTER
WATER
WEATHERING
ATMOSPHERES
CARBON COMPOUNDS
ELECTROMAGNETIC RADIATION
HYDROGEN COMPOUNDS
MATTER
OXYGEN COMPOUNDS
PLANETS
RADIATIONS
SOLAR SYSTEM EVOLUTION
SPECTRA
SULFUR COMPOUNDS
640107* - Astrophysics & Cosmology- Planetary Phenomena