jueves, 11 de junio de 2009
First Proof "Tight" Double Suns Can Have Planets
A ring of gas and dust surrounding a pair of sunlike stars is the first proof that planets can form around tightly orbiting stellar partners, new images reveal.
The ring was found around the binary star system V4046 Sagittarii, seen above in an artist's illustration as it might look from the surface of a distant asteroid.
Astronomers believe such rings are destined to condense into planets, comets, and asteroids similar to those in our solar system.
"V4046 has at least 50 Earth-masses of material in it," Rodriguez said June 10 during a meeting of the American Astronomical Society in Pasadena, California.
Planet-forming disks have been seen around binary star systems before. But the stars in those systems were very far apart from each other—from 20 to several hundred times the distance between Earth and the sun.
The new radio images show a disk around V4046 Sagittarii. The system's binary stars are separated by only 3,718,235 miles (5,983,920 kilometers), or a tenth of the distance between Mercury and the sun.
Finding a disk as part of this system suggests that planets can form just as easily around double stars as they can around single stars like our sun, said team member David Rodriguez of the University of California, Los Angeles.
This increases the number of planets that could exist outside our solar system, which in turn ups the odds that life may exist on one of those distant worlds.