Chemical regions
نویسندگان
چکیده
منابع مشابه
Chemical processes in star forming regions
This paper will review the basic concepts of gas–phase and grain surface chemistry of dense molecular clouds, where low mass and high mass stars form. The chemistry of cold pre-stellar cloud cores, where molecular freezeout and deuterium fractionation dominate, will be presented. Then, following cloud evolution after protostellar birth, hot core and shock chemistry will be discussed in view of ...
متن کاملChemical evolution of star-forming regions.
Recent advances in the understanding of the chemical processes that occur during all stages of the formation of stars, from the collapse of molecular clouds to the assemblage of icy planetesimals in protoplanetary accretion disks, are reviewed. Observational studies of the circumstellar material within 100-10,000 AU of the young star with (sub)millimeter single-dish telescopes, millimeter inter...
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We present the first results of an ongoing project to investigate the present-day chemical abundances of the extreme outer parts of galactic disks, as probed by the emission line spectra of a new sample of HII regions. The galaxies studied here, NGC 628, NGC 1058 and NGC 6946, are all late-type spiral galaxies, characterized by larger than average HI-to-optical sizes. Our deep Hα images have re...
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We have reexamined the origin of the apparent differentiation between nitrogen-bearing molecules and complex oxygen-bearing molecules that is observed in hot molecular cores associated with massive protostars. Observations show that methanol is an ubiquitous and abundant component of protostellar ices. Recent observations suggest that ammonia may constitute an appreciable fraction of the ices t...
متن کاملChemical differentiation in regions of high-mass star formation
Our goals are to compare the CS, N2H and dust distributions in a representative sample of high-mass star forming dense cores and to determine the physical and chemical properties of these cores. We compare the results of CS(5–4) and 1.2 mm continuum mapping of twelve dense cores from the southern hemisphere presented in this work, in combination with our previous N2H(1–0) and CS(2–1) data. We u...
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ژورنال
عنوان ژورنال: Nature
سال: 1983
ISSN: 0028-0836,1476-4687
DOI: 10.1038/305493b0