Free Astronomy Magazine November-December 2017

51 NOVEMBER-DECEMBER 2017 SPACE CHRONICLES T his ALMA image re- veals much finer structure in the U Antliae shell than has previ- ously been pos- sible. Around 2700 years ago, U Antliae went through a short period of rapid mass loss. Dur- ing this period of only a few hun- dred years, the material making up the shell seen in the new ALMA data was ejected at high speed. Examina- tion of this shell in further detail also shows some evidence of thin, wispy clouds known as fila- mentary sub- structures. [ALMA (ESO/ NAOJ/ NRAO)/F. Kerschbaum] ! body. Understanding the chemical composition of the shells and atmo- spheres of these stars, and how these shells form by mass loss, is im- portant to properly understand how stars evolve in the early Universe and also how galaxies evolved. Shells such as the one around U Antliae show a rich variety of chemical compounds based on carbon and other elements. They also help to recycle matter, and contribute up to 70% of the dust between stars. A stronomers have used ALMA to capture a strikingly beautiful view of a delicate bubble of ex- pelled material around the exotic red star U Antliae. These observa- tions will help astrono- mers to better understand how stars evolve during the later stages of their life-cycles. This short pod- cast takes a look at this important new result and what it means. [ESO] By displaying the different velocities we can cut this cosmic bubble into virtual slices just as we do in com- puter tomography of a human towards or away from the observer. This shell is also remarkable as it is very symmetrically round and also remarkably thin.