SN 2004et
SN 2004et was a bright Type II-P hypernova that occurred in the spiral galaxy NGC 6946, about 22 million light years away from Earth. The star that made the supernova was falsely identified to be a yellow supergiant but was then identified to be a type red supergiant of 13.8 solar masses. SN 2004et showed some rebrightening about 1,000 days after the initial supernova probably due to ejecta of circumstellar material or thermal echo. SN 2004et was one of the most luminous Type II-P supernovae ever recorded and characterized.