Free Astronomy Magazine November-December 2017

50 NOVEMBER-DECEMBER 2017 SPACE CHRONICLES During this period of only a few hundred years, the material making up the shell seen in the new ALMA data was ejected at high speed. Ex- amination of this shell in further de- tail also shows some evidence of thin, wispy gas clouds known as fil- amentary substructures. This spectacular view was only made possible by the unique ability to cre- ate sharp images at multiple wave- lengths that is provided by the ALMA radio telescope, located on the Chajnantor Plateau in Chile’s At- acama Desert. ALMA can see much finer structure in the U Antliae shell Ageing star blows off smoky bubble by ESO I n the faint southern constellation of Antlia (The Air Pump) the care- ful observer with binoculars will spot a very red star, which varies slightly in brightness from week to week. This very unusual star is called U Antliae and new observations with the Atacama Large Millime- ter/submillimeter Array (ALMA) are revealing a remarkably thin spheri- cal shell around it. U Antliae is a car- bon star, an evolved, cool and luminous star of the asymptotic giant branch type. Around 2700 years ago, U Antliae went through a short period of rapid mass loss. T his image from the Digitized Sky Survey 2 shows the very red car- bon star U Antliae and its surround- ings. [ESO, Digitized Sky Survey 2. Acknowledgement: Davide De Martin] than has previously been possible. The new ALMA data are not just a single image; ALMA produces a three-dimensional dataset (a data cube) with each slice being ob- served at a slightly different wave- length. Because of the Doppler Effect, this means that different slices of the data cube show images of gas moving at different speeds