Supernova impostor

They are also known as Type V supernovae, Eta Carinae analogs, and giant eruptions of luminous blue variables (LBV).

These impostors exceed their pre-outburst states by several magnitudes, with typical peak absolute visual magnitudes of −11 to −14, making these outbursts as bright as the most luminous stars.

The trigger mechanism of these outbursts remains unexplained, though it is thought to be caused by violating the classical Eddington luminosity limit, initiating severe mass loss.

One supernova impostor that made news after the fact was the one observed on October 20, 2004, in the galaxy UGC 4904 by Japanese amateur astronomer Kōichi Itagaki.

This LBV star exploded just two years later, on October 11, 2006, as supernova SN 2006jc.