In a new paper in ApJ and led by Eric Hsiao, a weird type 1a supernova has been seen growing in brightness ever so slowly, and the rise and fall in the brightness of certain spectral lines didn’t match what is generally expected. One theory, however, did correctly predict what they were seeing, showing theorists do sometimes get things totally right.
In this case, it appears that according to Hsiao: This is the first strong observational proof that a Type Ia supernova can explode in a post-AGB or proto-planetary-nebula system and is an important step in understanding the origins of Type Ia supernovae. These supernovae can be particularly troublesome because they can mix into the sample of normal supernovae used to study dark energy. This research gives us a better understanding of the possible origins of Type Ia supernovae and will help to improve future dark energy research.
“Carnegie Supernova Project II: The Slowest Rising Type Ia Supernova LSQ14fmg and Clues to the Origin of Super-Chandrasekhar/03fg-like Events,” E. Y. Hsiao et al., 2020 Sep. 10, Astrophysical Journal (preprint on arxiv.org)