Free Astronomy Magazine November-December 2018

51 NOVEMBER-DECEMBER 2018 SPACE CHRONICLES the Cat’s Paw Nebula (also known as NGC 6334I), a star-forming complex located about 4,300 light-years from Earth in the direction of the south- ern constellation Scorpius. Previous ALMA observations of this region at lower frequencies uncov- ered turbulent star formation, a highly dynamic environment, and a wealth of molecules inside the nebula. To observe at higher frequencies, the ALMA antennas are designed to accommodate a series of “bands” — numbered 1 to 10 — that each study a particular sliver of the spectrum. The Band 10 receivers observe at the highest frequency (shortest wave- lengths) of any of the ALMA instru- ments, covering wavelengths from 0.3 to 0.4 millime- ters (787 to 950 gigahertz), which is also considered to be long-wave- length infrared light. These first- o f - t h e i r - k i n d ALMA observa- tions with Band 10 produced two exciting results. One of ALMA’s first Band 10 re- sults was also one of the most chal- lenging, the di- rect observation of jets of water vapor streaming away from one of the massive proto- stars in the re- gion. ALMA was able to detect the s ubmi l l ime t e r- wavelength light naturally emitted by heavy water (water molecules made up of oxy- gen, hydrogen and deuterium atoms, which are hydrogen atoms with a proton and a neutron in their nucleus). “Normally, we wouldn’t be able to directly see this particular signal at all from the ground,” said Crystal Brogan, an astronomer at the NRAO and co-author on the paper. “Earth’s atmosphere, even at remarkably arid places, still contains enough of water vapor to com- pletely overwhelm this signal from any cosmic source. During excep- tionally pristine conditions in the high Atacama Desert, however, ALMA can in fact detect that signal. This is something no other telescope on Earth can achieve.” P ictured here is one of the cold cartridge assemblies of the Band 10 receiver, which gives ALMA its highest- frequency capabilities. [ALMA (ESO/NAOJ/NRAO)] As stars begin to form out of mas- sive clouds of dust and gas, the ma- terial surrounding the star falls onto the mass at the center. A portion of this material, however, is propelled away from the growing protostar as a pair of jets, which carry away gas and molecules, including water. The heavy water the researchers ob- served is flowing away from either a single protostar or a small cluster of protostars. These jets are oriented differently from what appear to be much larger and potentially more- mature jets emanating from the same region. The astronomers spec- ulate that the heavy-water jets seen by ALMA are relatively recent fea- tures just beginning to move out