Chemical evolution in the circumstellar structure of B5 IRS1

Kelly, M.L. and Macdonald, G.H. and Millar, T.J. (1996) Chemical evolution in the circumstellar structure of B5 IRS1. Monthly Notices of the Royal Astronomical Society, 279 (4). pp. 1210-1218. ISSN 0035-8711. (The full text of this publication is not available from this repository)

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Abstract

The B5 dark cloud has been identified as a site of low-mass star formation. We report a survey of a selection of the molecular species modelled by the B5 dynamical and chemical model of Charnley et al. at the positions of circumstellar HCN clumps in B5 IRS1. All of the key species observed yield either abundances or upper limits to abundances below both the standard and the predicted values, appearing to show evidence of depletion and/or destruction if the transitions observed are thermalized. Our results are not in good agreement with the model, and they bring into question the interpretation of the structure of B5 IRS1 proposed by Fuller et al. It was expected that HCN clump C might exhibit a higher excitation than HCN clump A, since it appeared to be located within the blueshifted molecular outflow. However, there is no significant difference observed between the two clumps, suggesting that the near-infrared and optical nebulosity is evidence of a reflection nebula rather than shocked material in the outflow. Finally, it is observed that our results are more consistent with gas-grain models than with those models excluding gas-grain interaction.

Item Type: Article
Subjects: Q Science > QB Astronomy
Divisions: Faculties > Science Technology and Medical Studies > School of Physical Sciences
Depositing User: R.F. Xu
Date Deposited: 04 Jun 2009 16:13
Last Modified: 04 Jun 2009 16:13
Resource URI: http://kar.kent.ac.uk/id/eprint/19281 (The current URI for this page, for reference purposes)
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