Astronomers say "wasteful galaxies" are blasting heavy elements off into deep space instead of recycling.
Contrary to what scientists previously thought, galaxies waste a stunning amount of heavy elements throughout the star formation process. According to a report from Phys.org, a study from astronomers at the University of Colorado, Boulder reveals that elements including oxygen, carbon and iron are much more abundant in the outer halos of galaxies than within the galaxies themselves.
The study reveals that when it comes to forming stars, conserving resources is an irrelevant consideration. Published in the Monthly Notices of the Royal Astronomical Society, the findings reveal that previous models may have overestimated the amount of raw materials available inside of a given galaxy’s star-forming region.
According to lead author and research associate at the Center for Astrophysics and Space Astronomy at CU Boulder, Benjamin Oppenheimer, “Previously, we thought that these heavier elements would be recycled into future generations of stars and contribute to building planetary systems. As it turns out, galaxies aren’t very good at recycling.”
Most of the elements that could be used for star formation, the study found, exist in the thin gaseous reservoir on the outskirts of the galaxy, called the circumgalactic medium, or CGM. While the average galaxy can be up to 100,000 light-years across, the CGM can range up to a million light-years.
“It takes massive amounts of energy from exploding supernovae and supermassive black holes to launch all these heavy elements into the CGM,” said Oppenheimer in a statement. “This is a violent and long-lasting process that can take over 10 billion years, which means that in a galaxy like the Milky Way, this highly ionized oxygen we’re observing has been there since before the Sun was born.”
A press release from the University of Colorado, Boulder describing the details of the study can be found here.