Journal ArticleDOI
Abundances of HCN and HNC in dark cloud cores
TLDR
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.Abstract:
We have determined the abundances of HCN and HNC toward 19 nearby dark cloud cores by observations of optically thin H13CN (J = 1-0) and HN13C (J = 1-0) lines. The column density of HCN is found to be correlated with that of HNC. The abundance ratio of [HNC]/[HCN] is determined to be 0.54-4.5 in the observed dark cloud cores. These results are consistent with the idea that HCN and HNC are produced mainly by a recombination reaction of HCNH+ with electrons in dark cloud cores. Furthermore, the [HNC]/[HCN] ratio does not show any significant differences between star-forming cores and starless cores. The HCN and HNC abundances are compared with those for the OMC-1 cores previously reported. Although the abundances of HCN in the OMC-1 cores are comparable to those in the dark cloud cores, the abundances of HNC in OMC-1 are 1-2 orders of magnitude less than those in dark cloud cores. It is suggested that HNC is destroyed by neutral-neutral reactions in high kinetic temperature regions.read more
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Journal ArticleDOI
An inventory of interstellar ices toward the embedded protostar W33A
Erika L. Gibb,Douglas C. B. Whittet,W. A. Schutte,Adwin Boogert,Adwin Boogert,Jean Chiar,Pascale Ehrenfreund,Perry A. Gerakines,Perry A. Gerakines,Jacqueline V. Keane,Alexander G. G. M. Tielens,E. F. van Dishoeck,O. Kerkhof +12 more
TL;DR: In this paper, a complete 2.4¨25 km spectrum of the dust-embedded young stellar object W33A was obtained with the Short Wavelength Spectrometer of the Infrared Space Observatory at a mean resolving power of D750.
Journal ArticleDOI
The 2009 edition of the GEISA spectroscopic database
N. Jacquinet-Husson,L. Crepeau,R. Armante,C. Boutammine,A. Chedin,N. A. Scott,C. Crevoisier,V. Capelle,C. Boone,N. Poulet-Crovisier,A. Barbe,Alain Campargue,D. Chris Benner,Yves Bénilan,Bruno Bézard,Vincent Boudon,Linda R. Brown,L. H. Coudert,Athena Coustenis,V. Dana,V. M. Devi,Sophie Fally,André Fayt,Jean-Marie Flaud,Aaron Goldman,Michel Herman,G. J. Harris,D. Jacquemart,Antoine Jolly,Isabelle Kleiner,Armin Kleinböhl,F. Kwabia-Tchana,Nina N. Lavrentieva,Nelly Lacome,Li-Hong Xu,O.M. Lyulin,J.-Y. Mandin,Arthur G. Maki,Semen Mikhailenko,Charles E. Miller,T.P. Mishina,Nasser Moazzen-Ahmadi,Holger S. P. Müller,Andrei Nikitin,Johannes Orphal,V.I. Perevalov,Agnes Perrin,Douglas T. Petkie,Adriana Predoi-Cross,Curtis P. Rinsland,John Remedios,Maud Rotger,Mary Ann H. Smith,Keeyoon Sung,S.A. Tashkun,Jonathan Tennyson,Robert A. Toth,Ann Carine Vandaele,J. Vander Auwera +58 more
TL;DR: The GEISA database as mentioned in this paper is a computer-accessible system comprising three independent sub-databases devoted, respectively, to: line parameters, infrared and ultraviolet/visible absorption cross-sections, microphysical and optical properties of atmospheric aerosols.
Journal ArticleDOI
Molecular inventories and chemical evolution of low-mass protostellar envelopes
TL;DR: In this paper, the chemistry of the envelopes around a sample of 18 low-mass pre- and protostellar objects for which physical properties have previously been derived from radiative transfer modeling of their dust continuum emission are reported.
Journal ArticleDOI
Tautomeric equilibria in relation to pi-electron delocalization.
Journal ArticleDOI
Molecular Evolution in Collapsing Prestellar Cores. III. Contraction of a Bonnor-Ebert Sphere
TL;DR: In this paper, the initial conditions of the core lie close to the critical Bonnor-Ebert sphere with a central density of ~104 cm-3 in one model (α = 1.1), while gravity overwhelms pressure in the other (α= 4.0), where α is the internal gravity-to-pressure ratio.
References
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Journal ArticleDOI
A survey for dense cores in dark clouds
TL;DR: In this paper, a total of 149 dark cloud positions were surveyed for evidence of dense cores in the (J,K) = (1,1) rotating inversion line of NH3.
Journal ArticleDOI
A survey of CCS, HC3N, HC5N, and NH3 toward dark cloud cores and their production chemistry
Hiroko Suzuki,Satoshi Yamamoto,Masatoshi Ohishi,Norio Kaifu,Shin-Ichi Ishikawa,Yasuhiro Hirahara,Shuro Takano +6 more
TL;DR: In this paper, the existence of a systematic relation between the chemical evolution and the physical evolution of dark clouds was examined in 49 dark cloud cores to examine the existence and relationship between the two.
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Shock Chemistry in the Young Bipolar Outflow L1157
TL;DR: In this paper, the authors present the first results from a recent survey of molecular lines in L1157, a highly collimated bipolar molecular outflow driven by a class 0 protostar.
Journal ArticleDOI
Molecular Abundances and Low-Mass Star Formation. II. Organic and Deuterated Species toward IRAS 16293-2422
TL;DR: In this article, the authors presented millimeter and submillimeter line surveys of the protobinary source IRAS 16293-2422 in the 230 and 345 GHz windows.