How do massive stars end their lives? This is one of the most fundamental questions in massive stellar evolution yet it remains unanswered. Theory suggests that stars with an initial mass above 20Msun end their lives as Type Ib/c core-collapse supernovae (ccSNe), however to date there is no direct observational confirmation. One candidate progenitor of Type Ibc ccSNe are evolved massive stars called Wolf Rayet (WR) stars but broad-band imaging has, so far, failed to identify the WR progenitor of 10 Type Ibc ccSNe. Does this indicate a binary progenitor or are the broad-band images simply not suitable? I present ongoing work searching for WR stars in several nearby star-forming galaxies, focusing on M101. We have obtained narrow-band high spatial resolution HST/WFC3 imaging, and I will show images of WR stars that are not detected in broad-band images. Moreover, analysis of the central M101 field shows a WR rich galaxy hosting over 1000 WR stars, a significant fraction of which we do not detect in our ground based surveys.
American Astronomical Society Meeting Abstracts #219
- Pub Date:
- January 2012