Free Astronomy Magazine May-June 2019

46 MAY-JUNE 2019 SPACE CHRONICLES formation process of the stars, that is the aggregation of cosmic gas and dust. Baby stars collect the gas with their gravitational pull, how- ever, some of the material is ejected by the protostars. This ejected ma- terial forms a stellar birth cry which provides clues to understand the process of mass accumulation. Yuko Matsushita, a graduate stu- dent at Kyushu University and her team used ALMA to observe the de- tailed structure of the birth cry from the baby star MMS5/OMC-3 and found two different gaseous flows: a slow outflow and a fast jet. There have been a handful of examples with two flows seen in radio waves, but MMS5/OMC-3 is exceptional. “Measuring the Doppler shift of the radio waves, we can estimate the speed and lifetime of the gas flows,” said Matsushita, the lead author of the research paper that appeared in The Astrophysical Jour- nal . “We found that the jet and out- flow were launched 500 years and 1300 years ago, respectively. These gas streams are quite young.” More interestingly, the team found that the axes of the two flows are misaligned by 17 degrees. The axis of the flows can be changed over by ALMA Observatory ALMA differentiates two birth cries from a single star A stronomers have unveiled the enigmatic origins of two different gas streams from a baby star. Using ALMA, they found that the slow outflow and the high speed jet from a protostar have mis- aligned axes and that the former started to be ejected earlier than the latter. The origins of these two flows have been a mystery, but these observa- tions provide telltale signs that these two streams were launched from different parts of the disk around the protostar. Stars in the Universe have a wide range of masses, ranging from hun- dreds of times the mass of the Sun to less than a tenth of that of the Sun. To understand the origin of this variety, astronomers study the A rtist’s impression of the baby star MMS5/OMC-3. ALMA obser- vations identified two gas streams from the protostar, a collimated fast jet and a wide-angle slow outflow, and found that the axes of the two gas flows are misaligned. [NAOJ]