Spitzer Space Telescope Infrared Spectrograph (IRS) Spectroscopy of the Prototype Wolf-Rayet Star EZ Canis Majoris (HD 50896)
Abstract
We present mid-infrared Spitzer Space Telescope Infrared Spectrograph (IRS) spectroscopy of the prototype WN star EZ Canis Majoris (HD 50896, WN4b). Numerous stellar wind lines of He II are revealed, plus fine-structure lines of [Ne III] 15.5 μm and [O IV] 25.9 μm. We carry out a spectroscopic analysis of HD 50896 allowing for line blanketing and clumping, which is compared to the mid-IR observations. We make use of these stellar properties to accurately derive Ne/He=(1.2-1.8)×10-4 and O/He=(4.2-4.8)×10-5 by number, for the first time in an early WN star. In addition, we obtain N/C~40 and N/O~50 by number, in perfect agreement with current predictions for rotating massive stars at the end of interior hydrogen burning.
- Publication:
-
The Astrophysical Journal Supplement Series
- Pub Date:
- September 2004
- DOI:
- 10.1086/422878
- Bibcode:
- 2004ApJS..154..413M
- Keywords:
-
- Infrared: Stars;
- Stars: Atmospheres;
- Stars: Individual: Henry Draper Number: HD 50896;
- Techniques: Spectroscopic