Star factories weren't all that common in the early universe because the first galaxies were smaller.
The smaller galaxies produced stars at a modest rate. Later, when the universe was a couple of billion years old, the vast majority of larger galaxies began to form and accumulate enough gas and dust to become prolific star factories. These star factories, called starburst galaxies, became prevalent a couple of billion years after the Big Bang.
This week, astronomers discovered the earliest starburst galaxy ever observed. Dubbed HFLS3, the galaxy is as massive as our Milky Way but churns out nearly 3,000 suns each year.
"This galaxy is just one spectacular example, but it's telling us that extremely vigorous star formation was possible early in the universe," said Jamie Bock, professor of physics at Caltech and a coauthor of the paper describing the findings in the April 18 issue of the journal Nature.
Another galaxy, called SMM J2135-0102, was discovered with the Atacama Pathfinder Experiment telescope in 2010. Astronomers estimate that SMM J2135-0102 is producing stars at a rate that is equivalent to about 250 suns per year. These star factories are similar in size to those in the Milky Way, but one hundred times more luminous.
Scientists determine how active star formation is by the presence of a wide variety of chemicals such as monoxide, ammonia, hydroxide, and even water. Such a diversity of elements indicates the galaxy is releasing them due to star formation activity.
About 250 million light-years away, The Hubble Space Telescope spotted 200 mammoth star clusters in Arp 220, a region near the constellation Serpens. The largest star factory in this area has enough matter to create 10 million suns.
The star-forming region 30 Doradus is a region located in the Large Magellanic Cloud, a dwarf irregular galaxy orbiting our own Milky Way. Scientists last year found a massive star that was thrown out of the region and is spiraling away at 2,485,480 miles per hour. This star, named 30 Dor 016, is about 90 times the mass of our sun.
Scientists think some of these star factories will continue to produce star clusters for millions of years before all the gas and dust inside is exhausted.