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The neon abundance in WC stars. II. ISO-SWS spectroscopy of WR 90 (HD 156385)

Published online by Cambridge University Press:  25 May 2016

Luc Dessart
Affiliation:
Department of Physics & Astronomy, UCL, Gower St., London, WC1E 6BT, UK
Allan J. Willis
Affiliation:
Department of Physics & Astronomy, UCL, Gower St., London, WC1E 6BT, UK
Paul A. Crowther
Affiliation:
Department of Physics & Astronomy, UCL, Gower St., London, WC1E 6BT, UK
Patrick W. Morris
Affiliation:
SRON, Sorbonnelaan 2, NL-3584 CA, Utrecht, the Netherlands
D. John Hillier
Affiliation:
Department of Physics & Astronomy, University of Pittsburgh, Pittsburgh, PA 15260, USA

Abstract

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In general, observationally derived wind compositions of WR stars are in reasonable agreement with predictions from stellar evolution models for massive stars. However, Barlow et al. (1988) identified a major discrepancy for neon in γ2 Vel (WC8+O) using ground-based observations. The advent of the ESA Infrared Space Observatory (ISO) has allowed the study of neon in many more WC stars, using mid-IR fine structure lines ([Ne II] 12.81 μm, [NeIII] 15.55μm and [NEV] 14.32 μm). Willis et al. (1998) used ISO-SWS observations of WR 146 (WC5+O) to derive a neon abundance that was within the range expected theoretically. Here we undertake a study of WR 90 (HD 156385), the only (apparently) single WC7 star in our Galaxy, using ISO-SWS spectroscopy. The only spectroscopic neon feature in the mid-IR of WR 90 is [Ne III] 15.55 μm, in addition to numerous C IV and He II transitions (see Figure 1).

Type
Part 2. Models for single star evolution of massive stars: wind + atmosphere + interior
Copyright
Copyright © Astronomical Society of the Pacific 1999 

References

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