Quadruple sunsets possible on other worlds

[Owlscrying]

July 25

Astronomers have spotted a dusty disk in a four-star solar system that could be home to a planet in the making. The system is still relatively young, at 10 million years old. One of its two pairs of stars is known to be circled by a dusty disk, which contains materials that are thought to clump together to form planets.

Using the infrared eyes of NASA's Spitzer Space Telescope, astronomers spotted the swirling disk around a pair of stars in the quadruple-star system HD 98800, located 150 light-years away in the constellation TW Hydrae.

If a planet did form in the disk, its sky would be bathed in the light of four suns. One pair of suns would blaze brightly, while the other pair, gravitationally bound to the first pair, would appear as little more than faint pinpoints of light.

So-called "circumstellar" disks like the one that rings HD 98800 can be the birthplace of planets. Most disks are smooth and continuous, but Spitzer detected a gap in the HD 98800 disk that could be evidence of one or more immature "protoplanets" carving out lanes in the dust.

Researchers spied two separate belts of material in the circumstellar disk. A swath of near-empty space separates the two belts, inside of which a budding planet might roam.

The stars that make up each stellar doublet orbit around each other, and the two pairs circle one another as well.

Recent surveys have revealed that the dusty debris disks that function like nurseries for new planets are as common around double star systems as they are around single ones. A few triple-star systems are even known.

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