Free Astronomy Magazine May-June 2022

18 MAY-JUNE 2022 ASTRO PUBLISHING mation of chaotic, stretched-out streams of dust and gas in the disk surrounding it. While such intruder-based flyby events have previously been wit- nessed with some regularity in com- puter simulations of star formation, few convincing direct observations have ever been made, and until now, the events have remained largely theoretical. “Observational evidence of flyby events is difficult to obtain because these events happen fast and it is difficult to capture them in action. What we have done with our ALMA Band 6 and VLA observations is equivalent to capturing lightning striking a tree,” said Ruobing Dong, an astronomer at the University of Victoria in Canada and the principal investigator on the new study. “This S cientists using the Atacama Large Millimeter/submillimeter Array (ALMA) and the Karl G. Jansky Very Large Array (VLA) made a rare detection of a likely stellar flyby event in the Z Canis Majoris (Z CMa) star system. An intruder—not bound to the system—object came in close proximity to and interacted with the environment surrounding the binary protostar, causing the for- by ALMA Observatory Bárbara Ferreira A rarely detected stellar flyby event