Neon Abundances from a Spitzer/IRS Survey of Wolf-Rayet Stars

Ignace, R; Cassinelli, J P; Tracy, G; Churchwell, E B; Lamers, H J G L M

Neon Abundances from a Spitzer/IRS Survey of Wolf-Rayet Stars

Authors

Description

We report on neon abundances derived from {\it Spitzer} high resolution spectral data of eight Wolf-Rayet (WR) stars using the forbidden line of [\ion{Ne}{3}] 15.56 microns. Our targets include four WN stars of subtypes 4--7, and four WC stars of subtypes 4--7. We derive ion fraction abundances $γ$ of Ne^{2+} for the winds of each star. The ion fraction abundance is a product of the ionization fraction $Q_{\rm i}$ in stage i and the abundance by number ${\cal A}_E$ of element E relative to all nuclei. Values generally consistent with solar are obtained for the WN stars, and values in excess of solar are obtained for the WC stars.
to appear in Astrophysical Journal