Free Astronomy Magazine March-April 2022

12 MARCH-APRIL 2022 ASTRO PUBLISHING Located 5000 m above sea level in Chile, the ALMA is sensitive to light with wavelengths around one mil- limeter, invisible to human eyes, but ideal for looking through the Milky Way’s layers of dusty interstellar clouds towards dust-enshrouded stars. “We were extra curious about these stars because they seem to be blowing out quantities of dust and gas into space, some in the form of jets with speeds up to 1.8 million kilometers per hour. We thought we might find out clues to how the jets were being created, but in- stead, we found much more than that” , says Theo Khouri, first author of the new study. The scientists used the telescope to measure signatures of carbon monoxide (CO) molecules in the light from the stars and compared U sing the gigantic telescope ALMA in Chile, a Chalmers-led team of scientists studied 15 unusual stars in our galaxy, the Milky Way, the closest 5000 light-years from Earth. Their measurements show that all the stars are double. All have recently experienced a rare phase that is poorly understood but probably leads to many other astro- nomical phenomena. Their results are published in the scientific jour- nal Nature Astronomy . By directing ALMA towards each star and meas- uring light from different molecules close to each star, the researchers hoped to find clues to their backsto- ries. Nicknamed “water fountains,” these stars were known to as- tronomers because of intense light from water molecules – produced by unusually dense and fast-moving gas. What happens when two stars share an atmosphere? by ALMA Observatory Nicolás Lira