Starlight robs galaxy of stellar ingredients

Starlight may be robbing a distant galaxy of the ingredients needed to make future stars, researchers report in the Dec. 4 Nature . A few billion suns’ worth of carbon monoxide is streaming out of SDSS J0905+57, a galaxy about 8 billion light-years away in the constellation Ursa Major. The observations may help astronomers figure out what controls how quickly stars form and what happens to the gas that doesn’t end up in stars.

SDSS J0905+57 is churning out new stars roughly 100 times as fast as the Milky Way. Astronomer James Geach of the University of Hertfordshire in England and colleagues found that intense light from many densely-packed stellar nurseries provides enough energy to push out the gas. At that rate, the galaxy will deplete its reserves of stellar ingredients in just 10 million years, after which it could become a galactic retirement home filled with aging stars.

Astronomers have debated whether starlight, stellar explosions or supermassive black holes force gas out of galaxies, eventually shutting down the star-building factories. These new results indicate that, while black holes and supernovas may still play a part, light from newborn stars is enough to drive out the gas and curtail future generations of stars.