Monday, May 07, 2007

Eta Carinae: no need to worry

Back before the dinosaurs, in a galaxy not so far away, a big star blew. We have similar one nearby ...
Huge star explodes in brightest supernova yet seen | Science | Reuters

WASHINGTON (Reuters) - A gargantuan explosion ripped apart a star perhaps 150 times more massive than our sun in a relatively nearby galaxy in the most powerful and brightest supernova ever observed, astronomers said on Monday.

... The supernova, designated as SN 2006gy, occurred 240 million light years away in a galaxy called NGC 1260, and was studied using observations from NASA's orbiting Chandra X-ray Observatory as well as earthbound optical telescopes...

... Astrophysicist Mario Livio said the supernova may have resulted from a type of explosion mechanism that had existed only in theoretical calculations. He said the first generation of stars in the universe may have died in such a manner.

In a normal supernova, the core of a star collapses when it exhausts its fuel, and forms either a neutron star or a black hole, with scant heavy elements blown into space.

But this supernova appears to be the result of the core not collapsing but being obliterated in an explosion blasting all its material into space, the scientists said.

Dave Pooley of the University of California at Berkeley said this star appears similar to Eta Carinae, a star perhaps 100 to 120 times the mass of the sun located 7,500 light years away within the Milky Way. There has not been a supernova in our galaxy in more than 400 years, Pooley said...

... If Eta Carinae were to burst into a supernova, Pooley said, "It would be so bright that you would see it during the day, and you could even read a book by its light at night."...

... "This could happen tomorrow, it could happen 1,000 years from now," Livio said. "Is there a risk to life on Earth as a result of this explosion? Well, not very likely."

Livio said Earth could be affected if there were a gamma ray burst that potentially could harm the atmosphere and life, but the chances of this aiming directly at Earth are slim.
When I read these stories I spare a moment to reflect on whatever was "downwind" from SN 2006gy.

I liked the "slim" comment. Really, I don't need to know how slim. If Eta Carinae's future gamma beam travels our way we're toast. Happily we have far more urgent things to worry about ...

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