Oldest Known Stars Found Near Milky Way Center
What are thought to be the oldest known stars have been found. They arose when the Universe was 300 million years old, before our Milky Way Galaxy even formed, and are now near the center of the Milky Way.
These mysterious and luminous balls of gas held together by their own gravity, the oldest formations of such that we know, are very pure but show material from an earlier star that died in a huge explosion called a hypernova. Researchers from University of Cambridge and The Australian National University (ANU) recently published a report on them in Nature.
"These pristine stars are among the oldest surviving stars in the Universe, and certainly the oldest stars we have ever seen," said Louise Howes from ANU and the study's lead author, in a release.
Essentially, the galaxy formed around these early-forming stars. The discovery of these nine, pure stars runs counter to current theories about what the early Universe was like. "The stars have surprisingly low levels of carbon, iron and other heavy elements, which suggests the first stars might not have exploded as normal supernovae," Howes said in the release.
The thought right now is that maybe they became hypernovae -- explosions of rapidly rotating stars that produced 10 times the energy of normal supernovae, Howes noted in a release.
The team used their ANU Skymapper telescope to sift through about five million stars to find the older stars. That telescope is able to detect the colors of anemic stars -- those that contain little iron -- and this ability was vital, the release said.
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