Free Astronomy Magazine May-June 2022

19 MAY-JUNE 2022 ASTRO PUBLISHING discovery shows that close encoun- ters between young stars harboring disks do happen in real life, and they are not just theoretical situations seen in computer simulations. Prior observational studies had seen fly- bys, but hadn’t been able to collect the comprehensive evidence we were able to obtain of the event at Z CMa.” Perturbations, or disturbances, like those at Z CMa aren’t typically caused by intruders, but rather by sibling stars growing up together in space. Hauyu Baobab Liu, an as- tronomer at the Institute of Astron- omy and Astrophysics at Academia Sinica in Taiwan and a co-author on the paper, said, “Most often, stars do not form in isolation. The twins, or even triplets or quadruplets, born together may be gravitationally at- tracted and, as a result, closely ap- proach each other. During these mo- ments, some material on the stars’ protoplanetary disks may be stripped off to form extended gas streams that provide clues to as- tronomers about the history of past stellar encounters.” Nicolás Cuello, an astrophysicist and Marie Curie Fellow at Université Grenoble Alpes in France and a co- S cientists have captured an intruder object disrupting the protoplanetary disk— birthplace of planets—in Z Canis Majors (Z CMa), a star in the Canis Majoris constellation. This artist’s impression shows the perturber leaving the star sys- tem, pulling a long stream of gas from the protoplanetary disk along with it. Ob- servational data from the Subaru Telescope, Karl G. Jansky Very Large Array, and Atacama Large Millimeter/submillimeter Array suggest the intruder object was re- sponsible for the creation of these gaseous streams, and its “visit” may have other as yet unknown impacts on the growth and development of planets in the star system. [ALMA (ESO/NAOJ/NRAO), B. Saxton (NRAO/AUI/NSF)]