As I understand it, the assumption behind using SN1a as standard candles is not that they all have exactly the same absolute brightness, but that there is a reliable relationship between the light curve (the curve of apparent brightness vs. time) and the absolute brightness. This relationship takes into account variation in the chemical composition of the supernova, which is what "doping" would affect.
However, what this particular paper seems to be saying is that there might not be just one light curve-brightness relationship, but two, corresponding to two different explosion processes. If that's true, astronomers would need to go back and review the SN1a data with this new classification scheme in mind.
However, what this particular paper seems to be saying is that there might not be just one light curve-brightness relationship, but two, corresponding to two different explosion processes. If that's true, astronomers would need to go back and review the SN1a data with this new classification scheme in mind.