The nearly 500 stars of the Milky Way are actually a family

“Most star clusters form together,” said study author Jeff Andrews, a postdoctoral fellow at Northwestern University, in a statement. “The interesting thing about Theia 456 is that it’s not a small group of stars together. It’s long and stretchy. There are relatively few streams close, young, and widely dispersed.”

Stars often form in globular clusters known as clusters. However, the newer data has revealed other patterns, such as these long jets, which astronomers believe occurred when star clusters separated or stretched.

“As we started to get more advanced in our hardware, technology, and ability to extract data, we found that stars are in more structures than clusters,” Andrews said. “Often they form these currents across the sky. Although we’ve known about them for decades, we are starting to find hidden streams.”

Theia 456 spans 570 light years across the Milky Way.

This stellar current has been hidden from astronomers for a long time because it lives at the level of the galaxy, where the current can easily be hidden by the 400 billion stars of the Milky Way. The galactic plane is where most of the galaxy’s mass is located.

Usually, stellar currents outside of our galaxy are found by telescopes heading away from the Milky Way.

“We tend to focus our telescopes in other directions because it’s easier to find things,” Andrews said. “Now we’re starting to find these currents in the galaxy itself. It’s like finding a needle in a haystack. Or, in this case, finding a ripple in the ocean.”

The stars within Theia 456 have a similar composition in that they all contain the same amount of iron. This indicates that the stars probably formed together about 100 million years ago.

Astronomers also looked at how the brightness of these stars changed over time and determined that the stars rotate at similar rates. This is further evidence that they are of the same age.

“If you know how the stars move, you can step back to see where the stars are,” Andrews said. “As we turned back the clock, the stars became closer and closer together. Therefore, we believe that all of these stars were born together and have a common origin.”

Revealing more about star formation in galaxies could lead to a greater understanding of the universe and how it became filled with galaxies and stars.