most luminous star

In 1997, astronomers using the Hubble Space Telescope (HST)) identified a star that could claim the record. They dubbed it the 'Pistol Star' from the shape of the nebula surrounding it. Though it releases up to 10 million times the power of the Sun, it is not visible to the naked eye since it lies 25,000 light years away, near the centre of the Milky Way, and is hidden by large clouds of dust. HST detected its infrared radiation, which can penetrate the dust. However, a problem with identifying truly superluminous stars is determining whether candidates really are single stars or close multiple systems. Before the claim of the Pistol Star, Eta Carinae would have been the most serious contender, with an estimated luminosity 4 million times the Sun's. Following an outburst in the mid- nineteenth century when it became the second brightest star in the sky, it has now dimmed because it is surrounded by a cloud of ejected material, probably several times the Sun's mass.