A star called S0-6 (circled in blue), was found near the supermassive black hole Sagittarius A* (Sgr A*, circled in green) at the center of the Milky Way.
Miyagi University of Education/ NAOJ
A star positioned near the center of the Milky Way seems to have come from outside of our galaxy. The interloper is thought to have traveled from a galaxy that has since disappeared. The star, called S0-6, could have traveled 50,000 light years to reach the Milky Way’s black hole.
Scientists have spotted a star near the center of the Milky Way that shouldn’t be there.
A study published Monday suggests SO-6, a star located about 0.04 light-years from the black hole at the center of our galaxy, could be an extragalactic star that traveled more than 50,000 light years to reach our galaxy’s heart.
This is the first study to show that a star from outside our galaxy could end up in the middle of it.
The findings could help explain a long-standing galactic mystery: where do stars near the black hole come from? Sagittarius A*, the black hole inside our galaxy, is supermassive so its gravity is too intense for stars to be born in that area.
A cross-section showing Sagittarius A* at the center of the Milky Way galaxy.
NASA
To identify its origins, a team of scientists led by Shogo Nishiyama at Miyagi University of Education in Japan, studied the stars’s composition using the Subaru Telescope, a 26-foot-wide observatory in Hawaii.
They found the star was made of chemicals more often seen in smaller galaxies that float outside the Milky Way, like the Small Magellanic Cloud and the Sagittarius dwarf galaxy.
The most likely theory is that SO-6 was born in a small galaxy that once orbited the Milky Way but has since disintegrated.
The orphaned star, which is at least 10 billion years old, would have then been grabbed by the Milky Way’s gravitational pull. It traveled at least 50,000 light years to reach Sagittarius A*, though it may have gone even farther than that as it’s more likely to have gone in a spiral rather than a straight line.
Scientists will now work to confirm the origin of SO-6, as well as determine if it traveled alone or with companions, lead scientist Nishiyama said.
“With further investigation, we hope to unravel the mysteries of stars near the supermassive black hole,” he added.