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Journal ArticleDOI

Radio wavelength observations of the L134N molecular core

Daryl A. Swade
- 01 Oct 1989 - 
- Vol. 71, Iss: 2, pp 219-244
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TLDR
A detailed study of the L134N dense molecular core through radio observations of spectral lines at millimeter and centimeter wavelengths is presented in this paper, where the prototypical dark cloud was chosen for the following reasons: it is a nearby cloud at a distance of 160 pc, and thus radio observations have high spatial resolution; it resides out of the galactic disk, providing unobscured viewing along the line of sight.
Abstract
A detailed study of the L134N dense molecular core through radio astronomical observations of spectral lines at millimeter and centimeter wavelengths is presented. The prototypical dark cloud was chosen for the following reasons: it is a nearby cloud at a distance of 160 pc, and thus radio observations have high spatial resolution; it resides out of the galactic disk, providing unobscured viewing along the line of sight; and it is known to be a rich source of molecular emission. The absence af any embedded infrared sources leads to the assumption that L134N is either in a stage of evolution prior to star formation or is a cloud in which internal support will prohibit a star from forming. A spectral line survey of 24 molecular transitions at up to seven positions in the L134N core, and observations of molecular emission from C18O, CSm, H13CO+, SO, NH3, and C3H2 are reviewed. Results indicate different spatial distributions for each species which may be attributed to variations in the excitation conditions for each transition or chemical abundance variations within the cloud core. Observational techniques and results are presented.

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Journal ArticleDOI

Abundances of HCN and HNC in dark cloud cores

TL;DR: In this article, the abundances of HCN and HNC toward 19 nearby dark cloud cores by observations of optically thin H13CN and HN13C (J = 1-0) lines were determined.
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Chemical and Physical Gradients along the OMC-1 Ridge

TL;DR: The principal result of this study is that along the extended quiescent ridge the chemical abundances, within factors of 3-4, exhibit an impressive degree of uniformity.
Book ChapterDOI

Molecular Abundance Variations Among and Within Cold, Dark Molecular Clouds

TL;DR: In this paper, the latest table of molecular abundances in the cold, dark clouds TMC-1 and L134N is presented and the molecular abundance variations between TMC -1 and l134N, those within TMC 1 and L 134N, and those among 49 dark cloud cores surveyed by Suzuki et al. are interpreted as an effect of chemical evolution.
Journal ArticleDOI

A Study of the Physics and Chemistry of L134N

TL;DR: In this paper, the authors carried out a comprehensive and self-consistent study of the physical and chemical state of the core of the dark cloud L134N (L183), whose molecular abundances provide a standard against which chemical models may be compared.
Journal ArticleDOI

On the frequency of N${_2}$H$^+$ and N${_2}$D${^+}$

TL;DR: In this article, the frequency of the first three rotational transitions of N2H+ and N2D+ and extrapolate to the next three transitions were adjusted to adjust the velocity differences between different tracers.
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