Free Astronomy Magazine November-December 2019

34 NOVEMBER-DECEMBER 2019 SPACE CHRONICLES A cosmic pretzel A stronomers using ALMA have obtained an ex- tremely high-resolution image showing two disks in which young stars are growing, fed by a complex pretzel-shaped network of filaments of gas and dust. Observing this remarkable phenomenon sheds new light on the earliest phases of the lives of stars and helps astronomers de- termine the conditions in which binary stars are born. The two baby stars were found in the [BHB2007] 11 system – the youngest member of a small stel- lar cluster in the Barnard 59 dark nebula, which is part of the clouds of interstellar dust called the Pipe nebula. Previous obser- vations of this binary system showed the outer structure. Now, thanks to the high resolu- tion of the Atacama Large Mil- limeter/submillimeter Array (ALMA) and an international team of astronomers led by sci- entists from the Max Planck In- stitute for Extraterrestrial Physics (MPE) in Germany, we can see the inner structure of this object. “We see two compact sources that we interpret as circumstel- lar disks around the two young stars,” explains Felipe Alves from MPE who led the study. A cir- cumstellar disk is the ring of dust and gas that surrounds a young star. The star accrete matter from the ring to grow bigger. “The size of each of these disks is similar to the asteroid belt by ESO T he Atacama Large Millimeter/submillimeter Array (ALMA) captured this unprece- dented image of two circumstellar disks, in which baby stars are growing, feeding with material from their surrounding birth disk. The complex network of dust structures distributed in spiral shapes remind of the loops of a pretzel. These observations shed new light on the earliest phases of the lives of stars and help astronomers determine the conditions in which binary stars are born. [ALMA (ESO/NAOJ/NRAO), Alves et al.]