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 \sim 200 R _ { \odot } — , is needed to reproduce the early light curve of SN 2011dh .
This is consistent with the suggestion that the yellow super-giant star detected at the location of the SN in deep pre-explosion images is the progenitor star .
From the main peak of the bolometric light curve and expansion velocities we constrain the mass of the ejecta to be \approx 2 M _ { \odot } , the explosion energy to be E = 6 - 10 \times 10 ^ { 50 } erg , and the ^ { 56 } Ni mass to be approximately 0.06 M _ { \odot } .
The progenitor star was composed of a helium core of 3 to 4 M _ { \odot } and a thin hydrogen-rich envelope of \approx 0.1 M _ { \odot } with a main sequence mass estimated to be in the range of 12–15 M _ { \odot } .
Our models rule out progenitors with helium-core masses larger than 8 M _ { \odot } , which correspond to M _ { \mathrm { ZAMS } } \gtrsim 25 M _ { \odot } .
This suggests that a single star evolutionary scenario for SN 2011dh is unlikely .