Isotopic abundances in interstellar cloudsResults of microwave measurements in dense interstellar clouds are discussed which pertain to determinations of relative isotopic abundances. Difficulties in deriving relative abundances from observations of the relative intensities of isotopic lines are examined, and measures available for coping with these complications are outlined. Results are presented concerning the relative abundances of C-13, O-17, O-18, N-15, Si-30, S-33, S-34, and D in a variety of interstellar clouds; the consistency of these results is evaluated. It is concluded that: (1) the relative abundances of C-13 and O-17 in interstellar clouds are generally higher than those in the solar system; (2) the abundances of N-15 and D are lower than the solar-system values; (3) the O-18 abundance is possibly higher than in the solar system; and (4) there are substantial variations in the isotopic abundances between different large interstellar clouds, with some of these variations not dependent on distance from the galactic center alone.
Document ID
19780028953
Acquisition Source
Legacy CDMS
Document Type
Conference Proceedings
Authors
Townes, C. H. (California, University Berkeley, Calif., United States)
Date Acquired
August 9, 2013
Publication Date
January 1, 1977
Subject Category
Astrophysics
Meeting Information
Meeting: Topics in interstellar matter; Commission 34 Session, General Assembly