An image captured by the observatory in Chile's Atacama desert is exciting astronomers.
Courtesy of the ALMA (Atacama Large Millimetre Array), astronomers have detected and photographed the presence of a disc around a planet outside our Solar System for the first time. This is important as it will shed new light on how moons and planets form in young stellar systems.
“Our work presents a clear detection of a disc in which satellites could be forming,” says Myriam Benisty, a researcher at the University of Grenoble, France, and at the University of Chile, who led the new research published in The Astrophysical Journal Letters. “Our ALMA observations were obtained at such exquisite resolution that we could clearly identify that the disc is associated with the planet and we are able to discern its size for the first time,” she adds.
The disc in question, called a circumplanetary disc, surrounds the exoplanet PDS 70c, one of two giant, Jupiter-like planets orbiting a star nearly 400 light-years away. Astronomers had found hints of a “moon-forming” disc around this exoplanet before but, since they could not clearly tell the disc apart from its surrounding environment, they could not confirm its detection - until now.
In addition, Benisty and her team found that the disc has about the same diameter as the distance from our Sun to the Earth (approx. 93 million miles) and enough mass to form up to three satellites the size of the Moon.
But the results are not only key to finding out how moons arise. “These new observations are also extremely important to prove theories of planet formation that could not be tested until now,” says Jaehan Bae, a researcher from the Earth and Planets Laboratory of the Carnegie Institution for Science, and author on the study.