Eta Carinae, one of the most massive stars in the Milky Way Galaxy, has been called a 'supernova in the making'. An outburst seen from the southern hemisphere in 1843 made it briefly the second brightest star in the night sky, although it is an estimated 9,000 light years from Earth. The star itself is not seen in this image. It is hidden by an elaborate nebulosity of gas and dust, produced by past eruptions. Yet infrared observations that penetrate the cloak of dust show that it is shining within, and recent observations with the HST have measured the rate at which matter continues to stream from the star.
The larger, red region of nebulosity is probably the most rapidly moving gas that erupted from Eta Carinae in the 1840s. Some of this outlying material is Moving at velocities in excess of two million miles per hour. The two pronounced lobes at the center of the picture shine so brightly because they contain huge numbers of microscopic dust particles that reflect or 'scatter' the light from the hidden central star.
Eta Carinae is about 4 million times more luminous than the Sun, and probably more than 100 times as massive. Presumably it will indeed become a supernova within the next few million years.
Technical Information: Composite made from images taken separately in red, green, and blue light.
Credit: J. Hester (Arizona State University), and NASA