CANBERRA, Australia Before the Milky Way galaxy came to be, a group of stars was already hanging out in its future neighborhood.
The nine stars formed prior to the universe turning 300 million years old, making them the oldest stars identified so far, according to Australian National University. Researchers believe the first stars were born within 200 million years of the Big Bang, but it is unknown whether any of those original stars are still intact.
"These pristine stars are among the oldest surviving stars in the universe, and certainly the oldest stars we have ever seen," lead author Louise Howes said in a statement. "These stars formed before the Milky Way, and the galaxy formed around them.
Researchers described the nine stars, which are located near the center of the Milky Way, as being surprisingly pure. Some of the materials in the stars appear to have come from an even older star that died in a hypernova, which researchers said can generate 10 times more energy than a typical supernova.
How pure a star is can indicate its age, according to researchers. They said they used SkyMapper to sift through 5 million stars in the dense, central areas of the Milky Way galaxy and determine which specimen were the purest. Then, they conducted a more in-depth examination of each stars makeup.
Researchers said they were surprised to discover the nine stars are extremely metal poor, with lower levels of carbon, iron and other heavy elements than they would expect. The finding would support the idea that the universes first stars ended as hypernovae instead of supernovae, according to Howes.
Findings from the study were published in Nature on Nov. 11.
The nine stars formed prior to the universe turning 300 million years old, making them the oldest stars identified so far, according to Australian National University. Researchers believe the first stars were born within 200 million years of the Big Bang, but it is unknown whether any of those original stars are still intact.
"These pristine stars are among the oldest surviving stars in the universe, and certainly the oldest stars we have ever seen," lead author Louise Howes said in a statement. "These stars formed before the Milky Way, and the galaxy formed around them.
Researchers described the nine stars, which are located near the center of the Milky Way, as being surprisingly pure. Some of the materials in the stars appear to have come from an even older star that died in a hypernova, which researchers said can generate 10 times more energy than a typical supernova.
How pure a star is can indicate its age, according to researchers. They said they used SkyMapper to sift through 5 million stars in the dense, central areas of the Milky Way galaxy and determine which specimen were the purest. Then, they conducted a more in-depth examination of each stars makeup.
Researchers said they were surprised to discover the nine stars are extremely metal poor, with lower levels of carbon, iron and other heavy elements than they would expect. The finding would support the idea that the universes first stars ended as hypernovae instead of supernovae, according to Howes.
Findings from the study were published in Nature on Nov. 11.