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ikenbot: Solar System’s Death Glimpsed in White Dwarf...

Sun, 06 May 2012 09:56:13 -0400

Solar System’s Death Glimpsed in White Dwarf Stars

Image: Three panels illustrate the death sequence of a planetary system. Four terrestrial planets orbit a sun-like star (top); the host star turns into a red giant and mixes up planetary orbits, causing them to collide (middle); dusty debris and asteroid-like objects are all that remains around the star, now a white dwarf (bottom). (Copyright of Mark A. Garlick/University of Warwick)

Four dead planetary systems, each lit by the burned-out core of a star that once resembled the sun, provide a harrowing forecast for Earth’s eventual demise.

Astronomers used the space-based Hubble telescope to probe the chemical signatures of dusty disks encircling the four star systems. In each they found a surprising abundance of elements that make up about 93 percent of Earth’s mass.

“What we are seeing today in these white dwarfs several hundred light years away could well be a snapshot of the very distant future of the Earth,” said Boris Gänsicke, an astrophysicist at the University of Warwick, in a press release.

Gänsicke and his team’s research on the white dwarfs, released May 1 on arXiv, suggests that the stars’ death throes pulverized the nearest planets, leaving only chunks of their cores. The team’s study is accepted for publication in the Monthly Notices of the Royal Astronomical Society.

The sun is about 4.57 billion years old and should survive another 5 billion years or so in its current state. After that it will run low on its hydrogen fuel, the fusion of which presently pushes away gas that would otherwise gather at its core. As the gas accumulates, rising pressure will fuse heavier helium atoms into carbon, drastically increasing the star’s core temperature.

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