Seminario "Observational evidence for 'islands of explodability' in massive stars"

CHARLISTA
Dr. Joseph Anderson
European Southern Observatory

TÍTULO
"Observational evidence for 'islands of explodability' in massive stars"

ABSTRACT
The majority of stars more massive than ~8Msun are expected to end their lives as core-collapse supernovae (CC SNe). During the last 15 years, this hypothesis has received significant support through the detection of progenitor stars on pre-explosion imaging, where the progenitors of the hydrogen-rich type II events (SNeII) have unambiguously been confirmed as Red Supergiants (RSGs). However, statistical analyses of these 'direct' progenitor detections has revealed a lack of >18Msun progenitors, which has led to the 'Red Supergiant problem': i.e. we observe stars in the local Universe more massive than this that are expected to explode as SNeII. One answer to this problem is that stars more massive than >18Msun do not explode to produce observable SNe, but collapse to produce black holes without any accompanying transient. Theory and modeling supports such a picture, with the possibility of 'islands of explodability' at higher progenitor masses: some stars explode while others do not. Here, I will give an overview of this research field outlining both the observational constraints and how this fits to the current theoretical understanding of massive star explosions. I will then present two specific observational cases: an observed RSG disappearing without any accompanying SN, and an observed SNII that we constraint to arise from a massive >20Msun progenitor.

Rene A. Mendez
Seminar Coordinator
DAS/UChile - rmendez@uchile.cl