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J.R. Maund (Institute of Astronomy, Cambridge, UK)
The nature of stars prior to explosion is of interest to the communities which study stellar evolution and the evolution and importance of SN explosions. All stars with main-sequence masses >8Msol are predicted to end their lives in a core-collapse induced explosion. Direct observations of the progenitors, to test these predictions, have been limited due to the unpredictable nature of SNe. The growth of publicly available archival imaging, from some of the world's largest telescopes as well as HST, has improved the chances of the fortuitous imaging of a progenitor. Here I present key results concerning the observed nature of the progenitors of core-collapse supernovae. Post-explosion HST imaging has been utilised, with the technique of differential astrometry, to confidently identify the progenitors in pre-explosion imaging. I will discuss the identified progenitor of the type II-plateau supernova 2003gd and the discovery of the signature of the hot binary companion to supernova 1993J. Supernova 2003gd was only the third supernova, after 1987A and 1993J, for which a progenitor has been identified. This progenitor was an M0 supergiant MZAMS=8+4-2Msol, the first time a red supergiant progenitor has been detected. The detected binary companion of the progenitor of SN1993J was determined, from latetime near-UV spectroscopy, to be a B0-4 supergiant with an estimated mass of 22Msol. The identified companion explains the peculiarities of 1993J and its progenitor photometry. I will also present mass limits for a number of supernova progenitors from pre-explosion imaging. In addition preliminary results concerning the nature of erupting Luminous Blue Variables, which appear photometrically and spectroscopically similar to type IIn supernovae, will also be presented. This work was conducted for my PhD thesis, under the supervision of Dr. Stephen Smartt, and was supported by a PPARC research studentship.
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Bulletin of the American Astronomical Society, 36 5
© 2004. The American Astronomical Society.