Mass limits for the progenitor star of supernova 2001du and other type II-P supernovae

Abstract

The supernova SN2001du in the galaxy NGC1365 (19+/-2Mpc), is a core-collapse event of type II-P. Images of this galaxy, have been taken with HST approximately 6.6 years before discovery and include the supernova position on the WFPC2 field of view. We have observed the supernova with the WFPC2 to allow accurate differential astrometry of SN2001du on the pre-explosion frames. There is a marginal detection (3-sigma) of a source close to the supernova position on the prediscovery V-band frame, however it is not precisely coincident and we do not believe it to be a robust detection of a point source. We conclude that there is no stellar progenitor at the supernova position and derive sensitivity limits of the prediscovery images which provide an upper mass limit for the progenitor star. We estimate that the progenitor had a mass of less than 15M_sol. We revisit two other nearby SNe II-P which have high quality pre-explosion images, and refine the upper mass limits for the progenitor stars. Finally we compile all the direct information available for the progenitors of eight nearby core-collapse supernovae and compare their mass estimates. These are compared with the latest stellar evolutionary models of pre-supernova evolution which have attempted to relate metallicity and mass to the supernovae type. Reasonable agreement is found for the lower mass events (generally the II-P), but some discrepancies appear at higher masses. (abridged).