Thursday

Linking supernovae to their elusive progenitor stars is a challenging task. Recent observations of supernovae taken only a few hours after explosion promise to be a game changer, allowing us to probe with unprecedented detail the last stages of massive star evolution and the interaction between the supernova and the circumstellar material ejected by the star shortly before its death. However, detailed radiative transfer simulations and quantitative spectroscopy are needed in order to completely understand and characterise these events. In this talk, I will present our recent efforts of investigating the nature of explosive eruptive events from massive stars and interacting SNe using the CMFGEN radiative transfer code. Our primary goal is to form a comprehensive understanding of the physical properties of massive stars shortly before explosion and then apply these models towards characterising specific events. I will discuss how the spectral morphology of these events change as a function of progenitor properties such as chemical abundances, mass loss, and wind velocity. Our models indicate a diversity of spectral morphologies and diagnostics, which could in turn be used to infer the nature of the progenitor of observed events. I will discuss our results for SN 2015bh, showing that an LBV with Teff = 15000K and L=8.5e5 Lsun was the progenitor of the explosive event in which the star lost 1e-3 Msun/yr in an outflow with velocity of 1000 km/s.