Astronomers Uncover Dozen New Long-Rising Type II Supernovae

Astronomers have discovered 12 new long-rising Type II supernovae as part of the Zwicky Transient Facility Census of the Local Universe, nearly doubling the number of known supernovae of this subclass. Type II supernovae are the result of the rapid collapse and violent explosion of massive stars, and are distinguished by the presence of hydrogen in their spectra. The newfound Type II supernovae have rise times ranging from 67 to 96 days and dome-shaped light curves in r-band photometry, and all have peak absolute magnitudes consistent with previous studies of the known long-rising Type II supernovae.