It may be the first planet ever to orbit three stars at once

The past few decades have shown that planets outside of our solar system are much more common than previously thought. Most revolve around a star, like us. Some are formed under stranger conditions, orbiting two stars. Now astronomers have found evidence for what may be the first known planet orbiting three stars at once.

The system in question, GW Orionis, is located 1300 light years away in the constellation Orion and is made up of two stars that revolve around each other every 241 days, with a third circling both. others in 11.5 years.

The system was already well known to astronomers for having a large protoplanetary disk – the donut of material from which planets form – which is made up of three misaligned rings. This is quite unusual, so astronomers wanted to better understand why the rings were misaligned. In a new article published in the Monthly Notices of the Royal Astronomical Society, astronomers used simulations to calculate how the disc got so misaligned and found a surprising result: it cannot be the three-star couple on its own. which causes it. Rather, they highlighted the presence of one or more massive undetected planets.

There is a huge gap between the innermost ring and the other two, about 15 billion kilometers in diameter. Some have tried to explain this massive discrepancy by suggesting it was caused by the three-star couple tearing their disc apart, but the team believes their suggestion of an unknown planet fits better.

“We show that the couple is not strong enough to break the record,” Dr. Jeremy Smallwood of the University of Nevada told IFLScience. “Next, we explored the scenario where a planet can dig space into the disk. We compared our simulation to the observations and they match up quite well.

The team examined different scenarios of the formation and / or evolution of planets with an inclination relative to the stars in the system. A massive planet traversing the disk will quickly gain mass, thus becoming larger – at least if the disk is thin enough. But if the disk is thicker, the gap that astronomers see should narrow over time, unless the planet is actually quite small. Thus, one planet, or several, could function in different scenarios.

If a planet or several planets are there, it will unfortunately not be easy to detect them. Misaligned or titled planets are quite difficult to spot using the transit method we use to find most exoplanets, where a dip in a star’s light suggests a body passing in front of it. It would not be impossible, however. The best evidence for the planet or planets would come from the system’s high-resolution imagery, although this accuracy may currently be beyond the capabilities of observatories as the system is still over 1,000 light years away.