Star ‘Families’ Stick Together in the Milky Way, Gaia Maps Reveal

Even in star clusters, families tend to stick together, and stellar “siblings” don’t leave each other’s sides for billions of years. 

Using data from the European Space Agency’s Gaia Observatory, scientists observed star formation in a large area of space that surrounds the Milky Way and found that stellar families, or stars that formed around the same time from the same cloud, stayed together in string-like groups.

“We generally thought young stars would leave their birth sites just a few million years after they form, completely losing ties with their original family,” Marina Kounkel, a researcher at Western Washington University and lead author of the study, said in a statement. “But it seems that stars can stay close to their siblings for as long as a few billion years.”

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The team analyzed the data using a machine learning algorithm and discovered around 2,000 previously unidentified star clusters that are around 3,000 light-years away from Earth. (A light-year is the distance a beam of light travels in a single Earth year, or 6 trillion miles or 9.7 trillion kilometers).

They also determined the age of hundreds of thousands of stars, which enabled them to identify which of the stars were considered “family.”

“Around half of these stars are found in long, string-like configurations that mirror features present within their giant birth clouds,” Kounkel said.

Determining the age of stars is no easy feat, since stars that formed at different times but have a similar mass tend to look pretty much alike. However, in order to find these clusters of familial stars, the team looked for stars moving in a similar fashion since stars that formed within the same birth cloud tend to move in a similar way, according to the statement. 

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