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Parameters of Warm Molecular Clouds from Methyl Acetylene Observations

A. V. Alakoz·S. V. Kalenskii·V. G. Promislov·L. E. B. Johansson·A. Winnberg
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Abstract

The results of a survey of 63 galactic star-forming regions in the 6_K-5_K and 5_K-4_K methyl acetylene lines at 102 and 85 GHz, respectively, are presented. Fourty-three sources were detected at 102 GHz, and twenty-five at 85 GHz. Emission was detected towards molecular clouds with kinetic temperatures 20-60 K (so-called ``warm clouds''). The CH3CCH abundances in these clouds appeared to be about several units X 10^(-9). Five mapped sources were analyzed using the maximum entropy method. The sizes of the mapped clouds fall within the range between 0.1 and 1.7 pc, virial masses - between 90-6200 Msun, and densities - between 6 X 10^4 and 6 X 10^5 cm^(-3). The CH3CCH sources spatially coincide with the CO and CS sources. Chemical evolution simulations showed that the typical methyl acetylene abundance in the observed clouds corresponds to an age of ~ 6 X 10^4 years.

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A. V. Alakoz, S. V. Kalenskii, V. G. Promislov, L. E. B. Johansson, A. Winnberg. 2002-05-21. Parameters of Warm Molecular Clouds from Methyl Acetylene Observations. https://doi.org/10.1134/1.1495032

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