Spiral Arms Point to Possible Planets in a Star’s Dusty Disk

Simulations of young stellar systems suggest that planets embedded in a circumstellar disk can produce many distinctive structures, including rings, gaps and spiral arms.
This video compares computer simulations of hypothetical systems to the Subaru image of SAO 206462.
A new image of the disk of gas and dust around a sun-like star is the first to show spiral-arm-like structures. These features may provide clues to the presence of embedded but as-yet-unseen planets.
The newly imaged disk surrounds SAO 206462, an 8.7-magnitude star located about 456 light-years away in the constellation Lupus.
Astronomers estimate that the system is only about 9 million years old. The gas-rich disk spans some 14 billion miles, which is more than twice the size of Pluto’s orbit in our own solar system.
The Subaru near-infrared image reveals a pair of spiral features arcing along the outer disk.
Theoretical models show that a single embedded planet may produce a spiral arm on each side of a disk.
The structures around SAO 206462 do not form a matched pair, suggesting the presence of two unseen worlds, one for each arm.

http://youtu.be/3i_zMsFLtno