A supergiant progenitor for SN 2011dh

BERSTEN; BENVENUTO; NOMOTO

Nikko

Simposio; Death of Massive Stars: Supernovae and Gamma-Ray Bursts; 2012

A set of hydrodynamical models based on stellar evolutionary progenitors  is used to study the nature of SN 2011dh. Our modeling suggests that a  large progenitor star - with R ~ 200 Rsun- is needed to  reproduce the early light curve (LC) of SN 2011dh. This is consistent  with the suggestion that the progenitor is a yellow super-giant star  detected at the location of the SN in deep pre-explosion images. From  the main peak of the bolometric light curve (LC) and expansion  velocities we constrain the mass of the ejecta to be ~2 Msun, the explosion energy to be E = 8 x 10^50 erg, and the 56Ni mass to be 0.063 Msun. The progenitor star is composed of a helium core of  ~4  Msun  and a thin hydrogen envelope, and it had a  main-sequence mass of ~13 Msun. Our models rule out  progenitors with helium-core masses larger than 8 Msun,  which correspond to MZAMS >~ 25 Msun. This suggests that a single evolutionary scenario for SN 2011dh is highly unlikely.