SN 2004et

SN 2004et is a bright type IIP^[1] supernova that occurred in the spiral galaxy NGC 6946 (The Fireworks Galaxy^[2]), about 22 million light years away from Earth.^[3] 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.^[4][5] SN 2004et was one of the most luminous type IIP supernovae ever recorded and characterized.^[6]

SN 2004et

Locations of SN 004et and SN 2017eaw in the Fireworks Galaxy, known for having many supernovas
Event type	Supernova
Type 2P
Date	c. 22 million years ago (discovered 2004)
Instrument	Spitzer Space Telescope
Constellation	Cygnus
Right ascension	20:35:25.330
Declination	+60:07:17.6
Epoch	J2000.0
Distance	c. 22 million ly
Host	Fireworks Galaxy
Progenitor	Red supergiant c. 13.8 solar masses
Peak apparent magnitude	20.89
Other designations	SN 2004et
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Discovery

SN 200et was discovered in 2004 and observed until 2009 by using the Spitzer InfarRed Array Camera,^[7] a ultra sensitive infrared space telescope that is used to study planets, stars, asteroids, comets, and galaxies.^[8]