Free Astronomy Magazine May-June 2019

57 MAY-JUNE 2019 SPACE CHRONICLES An in-depth study of these spectral spikes could provide insights about how the star is heating the disk, which would also be a useful meas- ure of the luminosity of the star. “When we look at the information ALMA has provided, we see about 60 different transitions – or unique fingerprints – of molecules like sodium chloride and potassium chlo- ride coming from the disk. That is both shocking and exciting,” said Brett McGuire, a chemist at the NRAO in Charlottesville, Virginia, and co-author on the paper. The researchers speculate that these salts come from dust grains that col- lided and spilled their contents into the surrounding disk. Their observations confirm that the salty regions trace the location of the circumstellar disk. A rtist impression of Orion Source I, a young, massive star about 1,500 light- years away. New ALMA observations detected a ring of salt — sodium chlo- ride, ordinary table salt — surrounding the star. This is the first detection of salts of any kind associated with a young star. The blue region (about 1/3 the way out from the center of the disk) represents the region where ALMA detected the mil- limeter-wavelength “glow” from the salts. [NRAO/AUI/NSF; S. Dagnello]