High energy X-rays emanating from a star 100 times more massive than the Sun and producing a million times more light, named Eta Carinae, has been discovered by the European Space Agency space probe Integral.

Integral spacecraftESA spacecraft Integral (INTErnational Gamma-Ray Astrophysics Lab)

Currently the most massive nearby star that can be studied in detail, Eta Carinae is part of the bipolar Homunculus Nebula, which surrounds the star. The nebula was created by a supernova eruption of Eta Carinae whose light first reached Earth in 1843.

Eta Carinae can been seen by the naked eye.

These star types are rare with only a few dozen found in galaxies the size of the Milky Way. Found in the constellation Carina, it is about 7,500 light years away. Violent winds of electrically charge particles bombard each other at thousands of miles per second emitting gamma rays and x-rays. The star is actually a binary system with a second large star orbiting the first.

Integral has provided instruments not previously available for measuring the high energy spectrum x-rays in addition to the gamma rays. The result of a shock wave effect produced when the individual star’s solar winds collide, these stars constantly shed particles off into space. Due to the colliding winds of radiation between these two stars, temperatures get extreme possibly reaching a billion plus degrees Kelvin.

Integral is examining the x-rays emissions of Eta Carinae to understand how stars evolve and create energy. Electrically-charged particles are trapped in the magnetic structure of the shock-wave and collide with low-energy photons, producing the emissions recently discovered by Integral. Astronomers believe this lies at the heart of many diverse phenomena in the universe.

 Diagram showing the position of Eta Carinae (among other objects) in the Carina nebula (NGC 3372).  Photograph by the Hubble Space Telescope.Carina Nebula

Since Earth is relatively close to Eta Carinae at 7,500 light years, the radiation could possibly reach our planet. The gamma rays and x-rays would be absorbed by our upper atmosphere, with possible degradation of the ozone layer. This would be problematic for spacecraft and satellites however. If the Carina system were to supernova, a possibility due to it mass, the light from the explosion would be enough to be prominently seen from Earth.

What is needed for the star to supernova is for it to reach the Eddington limit. This describes the effect when the outward pressure of radiation and the heat of the star created by the amount of its mass is so great as to overcome the effects of gravity. At this point, the star will explode as gravity is incapable of holding everything together.

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