Astronomers have found a "green" galaxy that converts gas into stars with an efficiency of almost 100 percent.
The astronomers made the discovery using the IRAM Plateau de Bure interferometer, the NASA Hubble Telescoope and Wide-field Infrared Survey Explorer. A news release from McGill University states that the galaxy is in a highly rare evolution phase, the most intense yet seen.
"This galaxy is remarkably efficient," lead author Jim Geach of McGill University said. "It's converting its gas supply into new stars at the maximum rate thought possible."
"While this galaxy is forming stars at a rate hundreds of times faster than our Milky Way galaxy, the sharp vision of Hubble revealed that the majority of the galaxy's starlight is being emitted by a region with a diameter just a few percent that of the Milky Way," he added.
Stars form in galaxies from collapsing clouds of gas. In most galaxies, just a small amount of the gas factors into star formation. With most of the gas dispersed throughout the galaxy, most new stars form in dense "knots" in the spiral arms. In this galaxy, however, called SDSSJ1506+54, almost all of the gas has been driven to the galaxy's core, resulting in a strong flare of star formation.
"We are seeing a rare phase of evolution that is the most extreme — and most efficient — yet observed," Geach said.
The efficiency of the galaxy is so great that in just a few moments of a galactic lifetime, star formation is likely to be complete. It will take only a few tens of millions of years for the gas in the galaxy to be used up, at which point it will turn into a massive elliptical galaxy.
