Astronomers Discover Giant Ancient Stars in Milky Way

Astronomers have discovered a mysterious group of giant elderly stars at the heart of the Milky Way that are emitting solar system-sized clouds of dust and gas. The stars, which have been named "old smokers," sat quietly for many years, fading almost to invisibility, before suddenly puffing out vast clouds of smoke. The discovery was made during the monitoring of almost a billion stars in infrared light during a 10-year survey of the night sky. The Guardian: The astronomers had set out to capture rarely seen newborn stars -- known as protostars -- while undergoing the equivalent of a stellar growth spurt. During these periods, young stars rapidly acquire mass by gorging on surrounding star-forming gas, leading to a sudden increase in luminosity. The team tracked hundreds of millions of stars and identified 32 erupting protostars that increased in brightness at least 40-fold and in some cases more than 300-fold. Another group of red giant stars near the centre of the Milky Way unexpectedly showed up in the analysis, however. When they were studied in more detail using the European Southern Observatory's Very Large Telescope, seven of the stars were deemed to be a new type of red giant star, which the researchers named "old smokers." Convection currents and instabilities within the star could trigger the release of enormous columns of smoke, Prof Philip Lucas of the University of Hertfordshire, who led the observations, suggested.

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