Infrared spectra of Uranus, Neptune, and Titan from 0. 8 to 2. 5 microns
The infrared spectra of Uranus and Titan at 3.6 cm/sup -1/ spectral resolution and of Neptune at 50 cm/sup -1/ spectral resolution are presented and analyzed. The spectra are dominated by strong methane absorptions, leaving only a few narrow windows for analysis. All spectra show strongly the effects of atmospheric scattering. It is demonstrated that the 3..nu../sub 3/ band of methane is at present not suitable for a reliable methane analysis on these objects. Rather, the methane column abundance is determined by using two newly observed weak methane bands at 6400 and 7900 cm/sup -1/. The C/H/sub 2/ mixing ratios derived from the CH/sub 4/ abundances are found to be quite similar for all the major planets, yielding a value of approx.2 x 10/sup -3/. Upper limits for a number of gases are derived, and a depletion of NH/sub 3/ and H/sub 2/S in the Uranus atmosphere is indicated.It is found that the Uranus atmosphere is clear to great depths, with its upper atmosphere depleted in CH/sub 4/. The pressure level where absorption due to CH/sub 4/ becomes significant is approx.1.0 atm (approx.1 bar). By contrast, Neptune's atmosphere has a cloud layer of variable height whose effects can be seen throughout its infrared spectrum. It is overlain by approx.50 km-amagat of H/sub 2/, placing the cloud deck at approx.0.7 atm (approx.0.7 bars).
- Research Organization:
- Lunar and Planetary Laboratory, University of Arizona
- OSTI ID:
- 5730338
- Journal Information:
- Astrophys. J.; (United States), Vol. 233:3
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GENERAL PHYSICS
NEPTUNE PLANET
INFRARED SPECTRA
PLANETARY ATMOSPHERES
SATURN PLANET
URANUS PLANET
ABUNDANCE
ALBEDO
CHEMICAL COMPOSITION
LINE WIDTHS
METHANE
RAYLEIGH SCATTERING
ALKANES
ATMOSPHERES
COHERENT SCATTERING
CRYOGENIC FLUIDS
FLUIDS
HYDROCARBONS
ORGANIC COMPOUNDS
PLANETS
SCATTERING
SPECTRA
640107* - Astrophysics & Cosmology- Planetary Phenomena