Astronomers Say Asteroid Belt Around Vega Suggests Multiple Planets Orbit Star
Posted on January 26, 2013
An asteroid belt was recently found around Vega, a bright star located about 25 light years from Earth. The asteroid belt was discovered by a team of astronomers from the University of Arizona (UA). The astronomers used data from NASA's Spitzer Space Telescope and the European Space Agency's Herschel Space Observatory.
The astronomers believe there are likely to be multiple planets orbiting Vega. This is due to the fact that the Vega has an outer comet-filled belt and then a large gap separating it from its inner asteroid belt. The astronomers believe planets (Jupiter-sized or smaller) exist in the gap. This would make the Vega system setup similar to our solar system. Below is a diagram (see larger version) that shows the Vega system compared to our solar system.
Kate Su, an astronomer at Steward Observatory at the UA, said in the announcement, "The wide gap between the two debris belts strongly suggests that multiple planets orbit these stars even though we can't see them. We know this because in systems without planets, the debris material is evenly distributed."
Su also explained the process called sculpting, where planets create gaps in debris disks. Su says, "Planets scatter the objects under their gravitational influence. Over time, you won't see any dust or planetesimals in the region where they reside."