Monodeuterated methane in the outer solar system. IV. Its detection and abundance on Neptune
- Paris Observatoire, Meudon (France) Lowell Observatory, Flagstaff, AZ (USA) New York State Univ., Stony Brook (USA) CNRS, Institut d'Astrophysique, Paris (France)
The 3nu2 band of CH3D was detected in the spectrum of Neptune near 1.6 micron recorded at a spectral resolution of 4/cm with the Cassegrain Fourier Transportation Spectrometer at the 3.6 m Canada-France-Hawaii Telescope (CFHT) on Mauna Kea. The analysis of this spectrum, using spectral synthesis techniques, yielded a CH3D/CH4 ratio of about 0.0006, which corresponds to a global D/H ratio for Neptune of about 0.00012, if CH3D is in isotopic fractionation equilibrium with HD. This value is about an order of magnitude larger than an earlier estimate by Orton et al. (1987) based on deconvolution measurements of unresolved molecular emission in the 8-10-micron region. Comparison of this new determination with previous studies of CH{sub 3}D in the outer solar system shows that, as in the case of Uranus, the D/H on Neptune is strongly enhanced over that found on Jupiter and Saturn and is comparable to the D/H in methane on Titan and in terrestrial methane and water. 39 refs.
- OSTI ID:
- 6642994
- Journal Information:
- Astrophysical Journal; (USA), Vol. 355; ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GENERAL PHYSICS
NEPTUNE PLANET
CHEMICAL COMPOSITION
COMPARATIVE EVALUATIONS
ELEMENT ABUNDANCE
FOURIER TRANSFORMATION
JUPITER PLANET
METHANE
OPTICS
PLANETARY ATMOSPHERES
SATURN PLANET
SOLAR SYSTEM
SPECTROSCOPY
URANUS PLANET
ABUNDANCE
ALKANES
ATMOSPHERES
HYDROCARBONS
INTEGRAL TRANSFORMATIONS
ORGANIC COMPOUNDS
PLANETS
TRANSFORMATIONS
640107* - Astrophysics & Cosmology- Planetary Phenomena