Astronomers observed what is believed to be the first signs of windy weather around a T Tauri star for the first time. The finding could help explain why some of these stars have odd discs that glow in infrared light while others shine in a more traditional fashion.
T Tauri stars resemble an infantile version of our own Sun and are surrounded by raw materials that can one day form rocky or gaseous planets, the National Radio Astronomy Observatory reported. The astronomers made their findings using the Atacama Large Millimeter/submillimeter Array (ALMA).
"The material in the disk of a T Tauri star usually, but not always, emits infrared radiation with a predictable energy distribution," said Colette Salyk, an astronomer with the National Optical Astronomical Observatory (NOAO) in Tucson, Ariz., and lead author on a paper published in the Astrophysical Journal. "Some T Tauri stars, however, like to act up by emitting infrared radiation in unexpected ways."
To explain these differences in infrared signatures the researchers suggested some may be emanating wind from within their protoplanetary discs. The winds could have an effect on planet formation by removing some of the dust essential in the creation of Jupiter-like objects. They could also stir up the discs and change the location of the planets' formation.
Using ALMA the researchers were able to study the distribution of carbon monoxide around the star despite the fact that it was 407 light-years away. Carbon monoxide allows researchers to track the molecular gas that makes up the star's planet-forming discs.
The researchers found gas would leave the disc's surface if wind were present, but the findings did not meet the researchers' exact predictions. The differences could be because the T Tauri star AS 205 N is actually part of a multiple star system with a binary star called AS 205 S. This means the gas could be pulled away by the binary partner rather than being ejected by wind.
"We are hoping these new ALMA observations help us better understand winds, but they have also left us with a new mystery," Salyk said. "Are we seeing winds, or interactions with the companion star?"
The team plans to keep searching for answers using ALMA observations in hopes of discovering the same phenomenon in other binary systems.
