Windy Weather Discovered in Young Planetary System

In order to learn more about what our solar system might have looked like in its early years, astronomers study T Tauri stars, which are similar to our Sun, but much younger. Scientists using the Atacama Large Millimeter/submillimeter Array (ALMA) discovered that a T Tauri star could be experiencing some fairly windy conditions, which could help answer some questions astronomers have had about planetary formation. The study was led by Colette Salyk of National Optical Astronomical Observatory (NOAO), and the paper was published in the Astrophysical Journal.

The T Tauri star in question is AS 205 N, located 407 light years away in the constellation Ophiuchus. AS 205 N is accompanied by a companion star, AS 205 S.

Some T Tauri stars are surrounded by a disc of dust and debris that will eventually form the star’s planetary system. When viewed through infrared and millimeter-wavelength light, these discs are expected to shine very brightly. Others, including AS 205 N, have an odd glow to them.

"The material in the disk of a T Tauri star usually, but not always, emits infrared radiation with a predictable energy distribution," Salyk explained in a press release. "Some T Tauri stars, however, like to act up by emitting infrared radiation in unexpected ways.”
Astronomers have previously predicted that this difference could be due to extremely windy conditions that are pushing the dust around, which can potentially interfere with the formation or location of gas giants, similar to Jupiter. However, there hasn’t been any previous evidence to support this claim.
Salyk’s team has been using ALMA to trace carbon monoxide signatures throughout the system, that indeed appeared to be blowing off the disc and ejected outward. Though they did find that the carbon monoxide was getting swirled around like it was heavily windy, it didn’t move quite as they had expected. Instead of getting chucked out of the system due to wind, it could be being stripped away by the companion star.
"We are hoping these new ALMA observations help us better understand winds, but they have also left us with a new mystery," said Salyk. "Are we seeing winds, or interactions with the companion star?”
In order to find out one way or another whether these conditions were caused by wind or just from interactions with the companion star, Salyk and her team will continue observing the system using ALMA. They will also target other T Tauri stars, including others that have companion stars, as well as those that do not. Through further study, they hope to blow the lid off of the mysteries surrounding these blustery pre-planetary conditions.