Monodeuterated methane in the outer solar system. IV. Its detection and abundance on Neptune

Journal Article · Fri Jun 01 04:00:00 EDT 1990 · Astrophysical Journal; (USA)

DOI:https://doi.org/10.1086/168799· OSTI ID:6642994

De Bergh, C; Lutz, B L; Owen, T; Maillard, J P ^[1]

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1. 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), Journal Name: Astrophysical Journal; (USA) Vol. 355; ISSN ASJOA; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

640107* -- Astrophysics & Cosmology-- Planetary Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ABUNDANCE
ALKANES
ATMOSPHERES
CHEMICAL COMPOSITION
COMPARATIVE EVALUATIONS
ELEMENT ABUNDANCE
FOURIER TRANSFORMATION
HYDROCARBONS
INTEGRAL TRANSFORMATIONS
JUPITER PLANET
METHANE
NEPTUNE PLANET
OPTICS
ORGANIC COMPOUNDS
PLANETARY ATMOSPHERES
PLANETS
SATURN PLANET
SOLAR SYSTEM
SPECTROSCOPY
TRANSFORMATIONS
URANUS PLANET