Tuesday, April 28, 2009

Even the stars die

NASA’s Hubble Space Telescope captured the colorful demise of another Sun-Like star that is some 4,000 light years away from us. This star is shedding off its outer layers of gas, which formed a cocoon around the star’s remaining core. During the process the star is releasing huge amounts of Ultraviolet light that is making it glow. The one just found by astronomers is much older and further away from us.

Astronomers see oldest object in universe yet:

WASHINGTON – Astronomers have spotted a burst of energy from a dying star, setting a record for the oldest and most distant object seen by Earth yet.

The 10-second blast was from when the universe was only 630 million years old.

NASA's Swift satellite spotted the gamma-ray burst, an explosion of high-powered radiation, on April 23. Then ground telescopes watched the afterglow and calculated it had traveled about 13.1 billion light years to get here. It beat old records by 100 or 200 hundred million light years.

NASA astrophysicist Neil Gehrels said the star's fiery death gave birth to a black hole. The star was only 1 million years old or so and was about 30 times the size of our sun.

GRB 090423: The Farthest Explosion Yet Measured
Credit: Gemini Observatory / NSF / AURA, D. Fox & A. Cucchiara (Penn State U.), and E. Berger (Harvard Univ.)

Explanation: An explosion so powerful it was seen clear across the visible universe was recorded in gamma-radiation last week by NASA's orbiting Swift Observatory. Farther than any known galaxy, quasar, or optical supernova, the gamma-ray burst recorded last week was clocked at redshift 8.2, making it the farthest explosion of any type yet detected. Occurring only 630 million years after the Big Bang, GRB 090423 detonated so early that astronomers had no direct evidence that anything explodable even existed back then. The faint infrared afterglow of GRB 090423 was recovered by large ground telescopes within minutes of being discovered. The afterglow is circled in the above picture taken by the large Gemini North Telescope in Hawaii, USA. An exciting possibility is that this gamma-ray burst occurred in one of the very first generation of stars and announced the birth of an early black hole. Surely, GRB 090423 provides unique data from a relatively unexplored epoch in our universe and a distant beacon from which the intervening universe can be studied.

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