SN 2004et

SN 2004et is a bright type IIP supernova that occurred in the spiral galaxy NGC 6946 (The Fireworks Galaxy ), 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. It was discovered alongside SN 2017eaw. 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 IIP supernovae ever recorded and characterized.

Discovery
SN 200et was discovered in 2004 and observed until 2009 by using the Spitzer InfarRed Array Camera, a ultra sensitive infrared space telescope that is used to study planets, stars, asteroids, comets, and galaxies.