SN 2005ap

SN 2005ap was a superluminous supernova (SLSN) discovered in 2005. It is notable for being one of the most luminous supernovae ever observed, and for exhibiting unusual spectral characteristics. It was located in the galaxy SDSS J130115.12+125911.8, at a redshift of z = 0.2836, corresponding to a comoving distance of approximately 1.37 gigaparsecs (4.47 billion light-years).

The supernova's peak absolute magnitude was estimated to be around -22.7, making it significantly brighter than typical Type Ia supernovae. The high luminosity and relatively slow decline rate indicated a large amount of energy release.

The progenitor star of SN 2005ap remains uncertain, but theories include pair-instability supernovae, or the explosion of a very massive star that has shed off a considerable amount of its outer layer before exploding. Some research suggests a possible connection to a magnetar as the energy source powering the extreme luminosity. Its peculiar spectrum and high luminosity continue to make it a subject of ongoing research and analysis in the field of astrophysics.