Rare Planet Found Orbiting Three Stars

It’s a hat-trick! Astronomers may have spotted the first ever known planet orbiting not one, not two, but three stars.

A team of astronomers used the Atacama Large Millimeter/submillimeter Array (ALMA) telescope to study the dusty disk around a newly-forming planetary system at GW Ori, a system 1,300 light-years away from the sun. GW Ori is what’s known as a hierarchical triple star system, meaning that two stars orbit each other with a third orbiting around the pair.

And the GW Ori system has rings – three of them. The dusty rings are a hallmark of active planetary formation, as that dust begins to slowly coalesce into larger planets.

But those rings have a large gap, and even stranger the three rings are all tilted relative to one another.

The researchers behind the study investigated all sorts of possibilities to explain the nature of the dusty rings, but couldn’t find an explanation…unless there’s a planet. If there is one or more massive, giant planet in the gap between the rings, its gravity combined with the triple nature of the star system is capable of tilting the remaining rings.

Gas giants, according to Jeremy Smallwood, lead author and a recent Ph.D. graduate in astronomy from the University of Nevada Las Vegas, are usually the first planets to form within a star system.

“It’s really exciting because it makes the theory of planet formation really robust,” Smallwood said. “It could mean that planet formation is much more active than we thought, which is pretty cool.”