Free Astronomy Magazine July-August 2019

38 JULY-AUGUST 2019 SPACE CHRONICLES University of Virginia in the USA and collaborators used the Atacama Large Millimeter/submillimeter Array (ALMA) to observe a molecular cloud that is collapsing to form two mas- sive protostars that will eventually become a binary star system. While it is known that most massive stars by ALMA Observatory Witnessing the birth of a massive binary star system S cientists from the RIKEN Cluster for Pioneering Research in Japan, the Chalmers University of Technology in Sweden, and the A LMA’s view of the IRAS- 07299 star-form- ing region and the massive bi- nary system at its center. The back- ground image shows dense, dusty streams of gas (shown in green) that ap- pear to be flow- ing towards the center. Gas mo- tions, as traced by the methanol molecule, that are towards us are shown in blue; motions away from us in red. The inset image shows a zoom-in view of the massive forming binary, with the brighter, primary protostar moving toward us is shown in blue and the fainter, secondary protostar moving away from us shown in red. The blue and red dotted lines show an example of orbits of the primary and secondary spiraling around their center of mass (marked by the cross).