What is Eta Carinae?
Eta Carinae is a remarkable hypergiant binary star located 7,500 to 8,000 light-years from the Earth in the constellation Carina, the keel. It is one of the most luminous stars known: either the fourth or the third, after LBV 1806-20 (according to some models), Cyg OB2-12, and HD 93129A. The Pistol Star, once thought to be the most luminous star in the Galaxy, is actually only the thirteenth. Like many of the other most massive stars, Eta Carinae is a luminous blue variable (LBV). Eta Carinae consists of two closely orbiting companion stars, Eta Carinae A and Eta Carinae B. The first contains 80 solar masses, the second 30. They maintain an eccentric orbit around each other, coming as close as 5 AU and separating as far as 30 AU. When the primary star formed, it may have contained as much as 200 solar masses, but the more massive a star is, the more energy it produces in its core, ejecting substantial portions of its outer envelope in the form of solar wind. Because many fusion reactio
Astronomers still do not know what lies at the heart of Eta Carinae, but most believe that it is powered by an extremely massive star that may be a hundred times as massive as the Sun. Such stars produce intense amounts of radiation that cause violent instabilities before they explode as a supernova. The outer rings seen by Chandra are evidence of an ancient eruption that preceded the 19th century “Great Eruption.” So, we can expect Eta Carinae will huff and puff a few times before it finally blows its own candle out in a true supernova. Further Chandra observations of Eta Carina are planned for the near future and should give astronomers deeper insight into this cryptic colossus. NASA’s Marshall Space Flight Center in Huntsville, AL, manages the Chandra program. TRW, Inc., Redondo Beach, CA, is the prime contractor for the spacecraft. The Smithsonian’s Chandra X-ray Center controls science and flight operations from Cambridge, MA.
Astronomers still do not know what lies at the heart of Eta Carinae, but most believe that it is powered by an extremely massive star that may be a 150 times as massive as the Sun. Such stars produce intense amounts of radiation that cause violent instabilities before they explode as a supernova. The outer rings seen by Chandra are evidence of an ancient eruption that preceded the 19th century “Great Eruption.” So, we can expect Eta Carinae will huff and puff a few times before it finally blows its own candle out in a true supernova. Further Chandra observations of Eta Carina are planned for the near future and should give astronomers deeper insight into this cryptic colossus. NASA’s Marshall Space Flight Center in Huntsville, AL, manages the Chandra program. TRW, Inc., Redondo Beach, CA, is the prime contractor for the spacecraft. The Smithsonian’s Chandra X-ray Center controls science and flight operations from Cambridge, MA.
