PHYSORG
In this artist’s conception, a captured world drifts at the outer edge of a distant star system, so far from its sun-like host that the star’s disk is barely resolvable at upper right. New research shows that one in 20 stars within our galaxy might have captured a free-floating planet. PHOTO/Christine Pulliam (CfA)
New research suggests that billions of stars in our galaxy have captured rogue planets that once roamed interstellar space. The nomad worlds, which were kicked out of the star systems in which they formed, occasionally find a new home with a different sun. This finding could explain the existence of some planets that orbit surprisingly far from their stars, and even the existence of a double-planet system.
“Stars trade planets just like baseball teams trade players,” said Hagai Perets of the Harvard-Smithsonian Center for Astrophysics.
The study, co-authored by Perets and Thijs Kouwenhoven of Peking University, China, will appear in the April 20th issue of The Astrophysical Journal.
To reach their conclusion, Perets and Kouwenhoven simulated young star clusters containing free-floating planets. They found that if the number of rogue planets equaled the number of stars, then 3 to 6 percent of the stars would grab a planet over time. The more massive a star, the more likely it is to snag a planet drifting by.
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