Hints of wandering planets in distant cometary belt

SANTIAGO, Chile, May 18 (UPI) -- For the first time, astronomers have captured high-resolution imagery of the cometary belt surrounding HR 8799, the only star system with multiple planets that have been directly photographed.

The resulting analysis suggests a disconnect between the cometary belt and the planets' orbital paths. One of two things explains the dissociative pattern: either the belt has shifted position over time or a hidden or wandering planet is affecting the belt's trajectory.

Researchers believe the latter explanation is more likely.

"These data really allow us to see the inner edge of this disk for the first time," Mark Booth, an astronomer at the Pontifical Catholic University of Chile, said in a news release. "By studying the interactions between the planets and the disk, this new observation shows that either the planets that we see have had different orbits in the past or there is at least one more planet in the system that is too small to have been detected."

Booth is the lead author of a new paper on the discovery, published this week in the Monthly Notices of the Royal Astronomical Society.

The belt of debris surrounding HR 8799 is populated by dust and icy fragments produced by constant cometary collisions. Scientists used Chile's Atacama Large Millimeter/submillimeter Array radio observatory to image the emissions of the belt's dust and debris.

HR8799 is located 129 light-years from Earth in vicinity of the constellation Pegasus. The relatively young star is roughly 1.5 times the mass of the Sun.

"This is the very first time that a multi-planet system with orbiting dust is imaged, allowing for direct comparison with the formation and dynamics of our own Solar System," added study co-author Antonio Hales, a researcher with the National Radio Astronomy Observatory in Charlottesville, Va.