Astronomers have presented the first-ever direct observations of a Type 1a supernova progenitor system. Astronomers have collected evidence indicating that the progenitor system of a Type 1a supernova contains a red giant star. They also show that the system previously underwent at least one much smaller nova eruption before it ended its life in a destructive supernova. By comparison, indirect observations of another Type 1a supernova progenitor system showed no evidence of a red giant star. Taken together, these observations unequivocally show that just because Type 1a supernovae look the same, that doesn't mean they are all born the same way.

Source: Supernovae of the same brightness, cut from vastly different cosmic cloth