Free Astronomy Magazine May-June 2020

32 MAY-JUNE 2020 SPACE CHRONICLES lae are formed. Sun-like stars evolve to puffed-up Red Giants in the final stage of their lives. Then, the star expels gas to form a remnant called a planetary nebula. There is a wide variety in the shapes of planetary nebulae; some are spherical, but others are bipolar or show compli- cated structures. Astronomers are interested in the origins of this vari- ety, but the thick dust and gas ex- pelled by an old star obscure the system and make it difficult to in- vestigate the inner-workings of the process. To tackle this problem, a team of astronomers led by Daniel Tafoya in Chalmers University of Technology, Sweden, pointed ALMA at W43A, an old star system in the constellation Aquila, the Eagle. Thanks to ALMA’s high resolution, the team obtained a very detailed view of the space around W43A. “The most notable structures are its small bipolar jets,” says Tafoya, the lead author of the research paper ALMA spots metamorph aged star A n international team of as- tronomers using the Atacama Large Millimeter/submillime- ter Array (ALMA) captured the very moment when an old star first starts to alter its environment. The star has ejected high-speed bipolar gas jets which are now colliding with the surrounding material; the age of the observed jet is estimated to be less than 60 years. These are key features to understand how the complex shapes of planetary nebu- by ALMA Observatory