File:Probing the Last Gasps of Doomed Star Eta Carinae.jpg

English: This illustration of unstable star pair Eta Carinae, released on September 9, 2009, following the success of Servicing Mission 4, shows how observations by the newly repaired Space Telescope Imaging Spectrograph (STIS) aboard NASA’s Hubble Space Telescope reveal some of the chemical elements that were ejected in the eruption seen in the middle of the 19th century.

The signature balloon-shaped clouds of gas blown from the pair of massive stars called Eta Carinae have tantalized astronomers for decades. Eta Carinae has a volatile temperament, prone to violent outbursts over the past 200 years.

STIS analyzed the chemical information along a narrow section of one of the giant lobes of gas. In the resulting spectrum, iron and nitrogen define the outer boundary of the massive wind, a stream of charged particles, from Eta Car A, the primary star. The amount of mass being carried away by the wind is the equivalent of one Sun every thousand years. While this "mass loss" may not sound very large, in fact it is an enormous rate among stars of all types. A very faint structure, seen in argon, is evidence of an interaction between winds from Eta Car A and those of Eta Car B, the hotter, less massive, secondary star.

The Hubble observations are part of the Hubble Servicing Mission 4 Early Release Observations. NASA astronauts repaired STIS during a servicing mission in May to upgrade and repair the Hubble telescope.

Credit: NASA, ESA, and the Hubble SM4 ERO Team