There’s now even more evidence that a strange star system perched on the constellation Orion’s nose may contain the rarest kind of planet in the known universe: a single globe circling three suns concurrently.
The star system, known as GW Orionis (or GW Ori) and situated approximately 1,300 light-years from Earth, provides a fascinating subject for research; with three dusty, orange rings nested within one another, the system actually appears like a huge bull’s-eye in the sky. At the center of that bull’s-eye dwell three stars — two locked in a tight binary orbit with each other, and a third swirling wildly around the other two.
Triple-star systems are uncommon in the universe, but GW Ori becomes more odd the closer scientists investigate. In a 2020 paper published in The Astrophysical Journal Letters, researchers took a close look at GW Ori with the Atacama Large Millimeter/submillimeter Array (ALMA) telescope in Chile, and discovered that the system’s three dust rings are actually misaligned with one another, with the innermost ring wobbling wildly in its orbit.
One hypothesis put forth by the researchers was the possibility of a young planet, or the beginnings of one, destabilizing the gravitational equilibrium of GW Ori’s complex triple-ring structure. The discovery of a triple-sun planet (also known as a “circumtriple” planet) would be the first time such a planet has been discovered in the known cosmos. Tatooine, you’re going to be eaten alive!
In a study published on September 17 in the journal Monthly Notices of the Royal Astronomical Society, astronomers provide new evidence for the existence of that uncommon planet. Using data from studies of other dust rings (also known as “protoplanetary disks”) elsewhere in the cosmos, the study’s authors performed 3D simulations to simulate how the unexplained gaps in the star system’s rings might have originated.
There were two theories explored by the team: either the break in GW Ori’s rings occurred as a result of the torque exerted by the three spinning stars at the system’s core, or the break occurred when a planet formed inside one of the rings.
The researchers came to the conclusion that there is not enough turbulence in the rings for the stellar torque hypothesis to be valid. They also found that As a result, the simulations indicate that the existence of a massive planet the size of Jupiter — or perhaps many planets — is the most likely explanation for the rings’ unusual form and behavior.
As lead research author Jeremy Smallwood of the University of Nevada, Las Vegas, told The New York Times, GW Ori may be “the first evidence of a circumtriple planet creating a gap in real time” if further studies of the system confirm that hypothesis.
Unfortunately, a hypothetical observer of this hypothetical planet would not be able to see all three suns rise and set in the sky because the two stars at the center of the system move in such a tight binary orbit that they appear as one great star, with the third swooping around them, according to the researchers.
Although it is unlikely that this world will be verified, the mere presence of this world would demonstrate that planets may develop under a broader range of circumstances than scientists had previously believed. Three suns and a wobbly jumble of dust rings aren’t enough to derail the plans of a newly formed planet, but what else could they possibly have in store?