2012ApJ...757...31B

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 R_☉–is needed to reproduce the early light curve (LC) of SN 2011dh. This is consistent with the suggestion that the yellow super-giant star detected at the location of the supernova (SN) in deep pre-explosion images is the progenitor star. From the main peak of the bolometric LC and expansion velocities, we constrain the mass of the ejecta to be ~2 M_☉, the explosion energy to be E = (6-10) x10⁵⁰ erg, and the ⁵⁶Ni mass to be approximately 0.06 M_☉. The progenitor star was composed of a helium core of 3-4 M_☉and a thin hydrogen-rich envelope of ~0.1M_☉ with a main-sequence mass estimated to be in the range of 12-15 M_☉. Our models rule out progenitors with helium-core masses larger than 8 M_☉, which correspond to M_ZAMS ≳ 25M_☉. This suggests that a single star evolutionary scenario for SN 2011dh is unlikely.