Eta Carinae outburst. Illustration of the expanding blast wave from the 1843 'Great Eruption' in the Eta Carinae system. This star was a hot blue supergiant surrounded by an older shell of gas (orange) ejected in a previous outburst about 1000 years ago. In the 1843 event, the stellar explosion created a two-lobed 'Homunculus' nebula (centre), plus an expanding fast shock wave (bright areas). Eta Carinae, over 100 times the mass of the Sun, is the most luminous star known in our galaxy. It radiates its energy at a rate 5 million times that of the Sun, and is extremely unstable. It is located in the constellation Carina, about 9000 light years from Earth.