Free Astronomy Magazine July-August 2020

38 JULY-AUGUST 2020 SPACE CHRONICLES SPHERE sees signs of planet birth by ESO D etailed view of the SPHERE op- tical bench is shown with the main subsystems clearly visible. SPHERE (Spectro-Polarimetric High- contrast Exoplanet REsearch) is installed on the ESO Very Large Tele- scope, and operates in direct imaging of exoplanets larger than Jupiter. [ESO] O bservations made with the European Southern Observa- tory’s Very Large Telescope (ESO’s VLT) have revealed the telltale signs of a planetary system being born. Around the young star AB Au- rigae lies a dense disc of dust and gas in which astronomers have spot- ted a prominent spiral structure with a ‘twist’ that marks the site where a planet may be forming. The ob- served feature could be the first di- rect evidence of a baby planet coming into existence. “Thousands of exoplanets have been identified so far, but little is known about how they form,” says Anthony Boccaletti who led the study from the Observatoire de Paris, PSL University, France. Astronomers know planets are born in dusty discs surround- ing young stars, like AB Auri- gae, as cold gas and dust clump together. The new ob- servations with ESO’s VLT, pub- lished in Astronomy & Astro- physics , provide crucial clues to help scientists better under- stand this process. “We need to observe very young systems to really cap- ture the moment when plan- ets form,” says Boccaletti. But until now astronomers had been unable to take sufficiently sharp and deep images of these young discs to find the ‘twist’ that marks the spot where a baby planet may be coming to existence. The new images feature a stunning spiral of dust and gas around AB Au- rigae, located 520 light-years away from Earth in the constellation of Auriga (The Charioteer). Spirals of this type signal the presence of baby planets, which ‘kick’ the gas, creat- ing “disturbances in the disc in the form of a wave, somewhat like the