Cool Stars 14 - Submitted Abstract # 179
This version created on 05 October 2006

Identification of near-UV predissociation lines of CH in
carbon-enhanced Fe-poor stars


B. Plez, Universite Montpellier 2
T. Masseron, Ohio State University 
S. Van Eck, Universite Libre de Bruxelles
A. Jorissen, Universite Libre de Bruxelles
P.F. Coheur, Universite Libre de Bruxelles
M. Godefroid, Universite Libre de Bruxelles
N. Christlieb, Hamburg University

In the course of a study of carbon-enhanced metal-poor (CEMP) stars,
we came across wide and shallow lines spread in the wavelength ranges
366-377nm and 392-413nm.  These lines appear to be predissociations
lines belonging to the CH B-X electronic transition system.  Due to
the much shortened lifetime of the upper levels that dissociate
through tunnel-effect, the lines are very broad.  We present a new
line list including these predissociation lines, and show comparisons
of calculated line profiles with observations of CEMP stars.  We
demonstrate that natural broadening alone does allow to reproduce the
observed lines.

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