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Neon abundances in three Wolf-Rayet stars observed with the ISO Short Wavelength Spectrometer

Published online by Cambridge University Press:  25 May 2016

Patrick W. Morris ,
Karel A. van der Hucht ,
Allan J. Willis ,
Luc Dessart ,
Paul A. Crowther  and
Peredur M. Williams
Patrick W. Morris*
Affiliation:
SRON, Sorbonnelaan 2, NL-3584 CA Utrecht, the Netherlands
Karel A. van der Hucht
Affiliation:
SRON, Sorbonnelaan 2, NL-3584 CA Utrecht, the Netherlands
Allan J. Willis
Affiliation:
Department of Physics & Astronomy, University College London, Gower St, London WC1E 6BT, UK
Luc Dessart
Affiliation:
Department of Physics & Astronomy, University College London, Gower St, London WC1E 6BT, UK
Paul A. Crowther
Affiliation:
Department of Physics & Astronomy, University College London, Gower St, London WC1E 6BT, UK
Peredur M. Williams
Affiliation:
Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ, UK
*
1Present address: Astronomical Institute, University of Amsterdam, the Netherlands

Extract

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We are motivated to study the Ne/He abundance ratio at the surfaces of Wolf-Rayet stars by evolutionary models, which have predicted enhancements by more than an order of magnitude over cosmic levels during the WC stage (e.g., Maeder 1991). This should occur early in the WC phase, as core-hydrogen is exhausted and the CNO bi-cycle gives way to the following chain of reactions for the Galactic stars:

The latest evolutionary models, which include the effects of interior mixing due to stellar rotation, indicate that the enhancement may be somewhat more gradual, but that the Ne/He ratio is essentially unchanged in its peak value, coinciding with complete H-depletion (e.g., Meynet, these Proceedings).

Type
Part 1. Basic observational properties of Wolf-Rayet stars and other hot massive stars
Information
Symposium - International Astronomical Union , Volume 193: Wolf-Rayet Phenomena in Massive Stars and Starburst Galaxies , 1999 , pp. 77 - 79
Copyright
Copyright © Astronomical Society of the Pacific 1999 

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