Astronomers at the University of Vienna have identified a river of stars passing through our galaxy and covering most of the southern sky. The 4,000 rated stars that make up the stream are born together and move together for the last one billion years, making the river a rarity, as most star clusters are rapidly dispersed when they form. do not contain enough stars to create enough gravity to hold the group together, and gravitational forces quickly disperse the stars across the galaxy. But by observing the nearby space, astronomers have found that there are several clusters with enough mass to remain bound for millions of years. The Vienna team managed to identify such a cluster relatively close to the Milky Way and map it with the help of the satellite of the European Space Agency, Gaia.
"Identifying nearby streams of discs is like searching for the proverbial needle in a haystack." Alves, one of the authors of the report, said in a statement. "Astronomers have long been watching and going through this new stream because it covers most of the night sky but only now realizes it is there and is huge and shocking near the sun. Finding things close to home is very useful, it means they are not too weak or too blurred for further detailed exploration, as astronomers dream. "
The team discovered the river by measuring the 3D motion of the stars in space, and seeing the stars moving together. Using the Gaea data, they managed to identify 200 stars in the river, but data show that at least 4,000 stars make up the stream. Because it is so old, this cluster has already traveled all the way around the galaxy four times, giving the gravitational forces time to pull the cluster into its lathe structure.
As the flow is nearby, it's an excellent potential. The purpose of planet-hunting missions can help us learn more about how stars move within galaxies.
The findings are published in the journal Astronomy & Astrophysics