Star explosion has experts abuzz

Astronomers have spotted a cataclysmic explosion that marked the death of a huge, distant star in a blast five times as bright and powerful as any they had seen previously. They said Monday a similar fate may be imminent for a star in Earth’s galactic neighborhood.

The size and energy of the newly recorded blast, 240 million light years away, has already begun to transform scientific understanding of how especially large stars explode, and has left awestruck researchers concerned – and a little excited – about what might happen to the similarly enormous and unstable star closer to home.

If that star, named Eta Carinae, blows up like the one just discovered, they said, it could possibly spew dangerous radiation in Earth’s direction.

The new discovery of a massive star exploding in a runaway thermonuclear reaction is especially exciting for scientists.

“This was a truly monstrous explosion, a hundred times more energetic than a typical supernova,” astronomer Nathan Smith of the University of California at Berkeley said of the exploded star, called SN 2006gy.

“It’s so powerful that it requires a new explanation of how massive stars explode,” Smith said.

Stars approaching this enormous size generally implode when they become unstable, leaving behind a black hole or a neutron star, a cold, extremely dense remnant. Astronomers considered it theoretically possible that such a massive star could instead explode and not collapse into a black hole, but they had never before seen it.

Mario Livio, of the Space Telescope Science Institute in Baltimore, said that enormous Eta Carinae, 7,500 light years away in our own Milky Way galaxy, has many features similar to the newly discovered exploded star.

Explosions of massive stars generally emit jets of intense gamma radiation. But because the gamma ray jets tend to be relatively narrow, the odds are that it would miss Earth.