A newly discovered star outside the Milky Way has yielded important clues about the evolution of our galaxy. Located in the dwarf galaxy Sculptor some 280,000 light-years away, the star has a chemical make-up similar to the Milky Way's oldest stars, supporting theories that our galaxy grew by absorbing dwarf galaxies and other galactic building blocks. Some recent studies had questioned the link between dwarf galaxies and the Milky Way, citing differences between the chemistry of their stars. But the differences may not be so big after all, according to new research published in Nature. "It was a question of finding the right kind of star, and doing that required some new techniques," says Josh Simon , an astronomer at the Observatories of the Carnegie Institution and a member of team that confirmed the star's telltale chemistry. Using earlier techniques, he says, "it was very difficult to recognize exactly which stars were the key ones to study."
"This star is likely almost as old as the universe itself," said astronomer Anna Frebel of the Harvard-Smithsonian Center for Astrophysics, lead author of the Nature paper reporting the finding.
In addition to the star's total metal abundance, researchers also compared the abundance of iron to that of elements such as magnesium, calcium, and titanium. The ratios resembled those of old Milky Way stars, lending more support to the idea that these stars originally formed in dwarf galaxies.
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