SN 2005df was a Type Ia supernova in the barred spiral galaxyNGC 1559, which is located in the southern constellation of Reticulum. The event was discovered in Australia by Robert Evans on the early morning of August 5, 2005[3] with a 13.8 magnitude,[2] and was confirmed by A. Gilmore on August 6.[7] The supernova was classified as Type Ia by M. Salvo and associates.[8][5] It was positioned at an offset of 15.0″ east and 40.0″ north of the galaxy's nucleus,[2] reaching a maximum brightness of 12.3 on August 18.[7] The supernova luminosity appeared unreddened by dust from its host galaxy.[9]
The progenitor was a carbon-oxygen white dwarf close to the Chandrasekhar limit, making a merger scenario unlikely. Modelling of the explosion shows a low central density for a hydrogen accretion scenario, suggesting the donating companion was a helium star or a tidally-disrupted white dwarf. Alternatively, the progenitor may have undergone some form of central mixing.[5]
^ abcdefgBarbon, R.; et al. (2008). "Asiago Supernova Catalogue". CDS/ADC Collection of Electronic Catalogues. 1. Bibcode:2008yCat....1.2024B.
^ abcEvans, R.; Gilmore, A. (August 2005). Green, D. W. E. (ed.). "Supernovae 2005dd, 2005de, and 2005df". IAU Circular. 8580 (2): 2. Bibcode:2005IAUC.8580....2E.