The chemical evolution in a model of contracting cloud

• Published in: Earth, moon, and planets Vol. 75; no. 1; pp. 25 - 39
• Main Authors: Amin, M. Y., El-Nawawy, M. S.
• Format: Journal Article
• Language: English
• Published: 01-01-1996
• ISSN: 0167-9295; 1573-0794
• DOI: 10.1007/BF00056286

The evolution of the different chemical species are followed in a model of contracting interstellar cloud. The central density increases from n = 10/cu cm in a diffuse initial cloud model to a dense cloud with central density number of n above 10 exp 5/cu cm, after a time of 1.2 x 10 exp 7 yr. A network of 622 reactions has been involved. The chemistry of the cloud is integrated simultaneously with the hydrodynamic equations of contraction. The results predict that the different molecular species increase in abundance as the contraction proceeds. The species which enhance significantly are CO, HCO, CS and NO. The fractional abundances of many of the other molecular species increase distinctly with contraction, e.g. CH, C2H, CN, SO2, CO2, H2O, C2, NH3, HCN, SO, OCS and SN. The transformation of the initial diffuse cloud model with small abundances of molecular species to a dense molecular cloud with enhancement of the different molecular species is confirmed. The results predict good agreements of our results with both observations and other theoretical studies. (Author)