Tuesday, January 06, 2004

The Light that Burns Twice as Bright ...

... burns for half as long. An interesting AP report on the massive star recently discovered on the other edge of our galaxy.

ATLANTA (AP) -- The most massive and brightest star known is 5 million to 40 million times more luminous than the Earth's own star, the sun, and about 150 times more massive, but this stellar giant is destined to live a short life and then to erupt in a supernova explosion.

Astronomer Stephen Eikenberry of the University of Florida said the star, known as LBV1806-20, is on the edge of a cluster of stars on the far side of the Milky Way, some 45,000 light-years from the solar system.

In a presentation Monday at the national meeting of the American Astronomical Society, Eikenberry said the star burns at a temperature of 30,000 degrees to 60,000 degrees and has ballooned out to a diameter 200 times that of the sun.

The huge star actually defies theories of massive star formation, he said. Usually massive stars grow no bigger than about 100 solar masses. At that point, the energy outflow is so powerful that additional material is blown away.

LBV1806-20, however, formed near where a supernova exploded in the past. Eikenberry said this explosion may have compressed gas and dust, enabling the star to grow far beyond the usual size of stellar giants. He said the same area contains a baby star in the process of formation, along with several other large stars, all of which may have formed as the result of the earlier supernova.

Eikenberry said massive stars generally only shine for about 2 million years, and LBV1806-20 is now middle-aged, about a million years old. Eventually, he said, such stars blow themselves apart and that without such explosions there would be no planets like the Earth teeming with life.(emphasis added)

As Carl Sagan said in his "Cosmos" series, "we are star stuff." The carbon, nitrogen, oxygen and other elements that constitute our bodies are the end-products of stellar supernovae that scattered these products of stellar fusion far and wide across the universe. I always find it awe-inspiring to ponder the reality that I and the seemingly mundane world around me are the results of such grand phenomena, and I think we owe a debt of gratitude to physicists like Hans Bethe for unravelling the secrets of nuclear fusion in stars.