Scientists believe they have observed a planet being formed for the first time. In a study published in Astronomy & Astrophysics today, a team of astronomers explain how they captured images of a young star, AB Aurigae, 520 light-years from Earth. In a massive disc of swirling gas and dust around the star, they detected a distinct twist, which could indicate where a new planet is forming and validate a major theory about planetary formation.
The discovery was made using the European Space Observatory’s Very Large Telescope (ESO’s VLT) and its SPHERE instrument. In 2019 and early 2020, astronomers from Belgium, France, Taiwan and the US obtained the deepest images of the AB Aurigae system to date. They confirmed past observations of spiral arms of gas and dust, and they discovered the critical twist, which is located about as far from the star as Neptune is from the Sun. They believe that the twist marks the spot of new planet forming.
"The twist is expected from some theoretical models of planet formation,” co-author Anne Dutrey said in a statement. “It corresponds to the connection of two spirals — one winding inwards of the planet’s orbit, the other expanding outwards — which join at the planet location. They allow gas and dust from the disc to accrete onto the forming planet and make it grow."
As instruments become more powerful (ESO is building a 39-meter Extremely Large Telescope), astronomers should be able to learn even more about the AB Aurigae system and how planets form.
“We should be able to see directly and more precisely how the dynamics of the gas contributes to the formation of planets,” said Anthony Boccaletti, who led the study.