Abstract:
Among the controversial issues on Type Ia supernovae (SNe Ia), we discuss (1) the evolutionary paths of the progenitor systems to SNe Ia, especially, the thermal stability of hydrogen shell burning in accreting white dwarfs, and (2) SN 2005hk which belongs to the very peculiar 2002cx-like group of SNe Ia. For SN 2005hk, we show our observations of the light curve and late time spectra, and present a preliminary model for the light curve to confirm it is quite a low energy explosion