POSTER PAPER 11.03
Partial Redistribution in the H Lyman Lines of Late-type Stars.
S. A. Sim
Institute: Department of Physics (Theoretical Physics), University of Oxford
Contact Email: sim@thphys.ox.ac.uk
Abstract:
The effects of partial redistribution (PRD) in the formation of the hydrogen Lyman alpha and beta lines are discussed with reference to simple atmospheric models of several late-type stars at different evolutionary stages. Radiative transfer calculations have been carried out using Carlsson's MULTI code which has been modified to include PRD by Hubeny & Lites. It is demonstrated that there is a rapid escalation in the importance of PRD in stars with surface gravity lower than the Sun, and that line profiles predicted using PRD are in significantly better agreement with observations than are those calculated assuming complete redistribution (CRD). The effects of PRD in H Lyman alpha on calculations of Fe II fluorescent spectra are examined, and it is found that there are significant, systematic differences between fluorescent spectra calculated using a PRD rather than CRD treatment of the pumping line.
Index Keywords: Aldebaran; Pollux; Procyon; CRD; PRD; Hydrogen
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Manuscript submitted: 2001-Aug-22
"The Future of Cool-Star Astrophysics", 2003, Eds. A. Brown,
G. M. Harper, & T. R. Ayres.
Proceedings of 12th Cambridge Workshop on Cool Stars, Stellar Systems,
& The Sun,
© 2003 University of Colorado.