Little, L.T. and Gibb, A.G. and Heaton, B.D. and Ellison, B.N. and Claude, S.M.X. (1994) The CI/CO ratio in the molecular cloud G-34.3+0.2. Monthly Notices of the Royal Astronomical Society, 271 (3). pp. 649-661. ISSN 0035-8711.
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A model for the structure of the massive molecular cloud G 34.3 + 0.2 is derived from extensive observations of carbon monoxide lines, including J = 1-0, J = 2-1, J = 3-2 and J = 6-5 (CO)-C-13, and J = 2-1 (CO)-O-18. The model consists of a slowly collapsing turbulent cloud with density constant out to a radius of 0.15 pc, but falling off as similar to R(-2) out to 3.25 pc. The CO abundance is constant. Within the framework of the basic cloud structure it is possible to predict line shapes for the 492-GHz P-3(1)-P-3(0) CI line, for different assumed radial behaviour of the CI abundance. These are compared with observations. The best fit is found with CI proportional to r(0.9) from the perimeter of the cloud into r = 0.24 pc where A(v)= 55. The column-density-averaged [CI]/[CO] ratio for G 34.3 + 0.2 is very similar to that for the rho Ophiuchi molecular cloud, notwithstanding the very different structures of the two clouds. Models for producing high carbon abundances deep in clouds that may have difficulty in explaining the results include those with external ultraviolet penetration around clumps, or dynamic mixing, or in which the initial [C]/[O] ratio is greater than unity.
|Uncontrolled keywords:||line, profiles; ism, abundances; ism, clouds; ism, individual, g 34.3 + 0.2; ism, molecules; radio lines, ism|
|Subjects:||Q Science > QB Astronomy|
|Divisions:||Faculties > Science Technology and Medical Studies > School of Engineering and Digital Arts|
|Depositing User:||O.O. Odanye|
|Date Deposited:||08 Jul 2009 11:41|
|Last Modified:||28 May 2012 14:16|
|Resource URI:||http://kar.kent.ac.uk/id/eprint/19862 (The current URI for this page, for reference purposes)|
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