If you live in the southern hemisphere of the Earth, it is likely that you can see some of the stars of a newly identified cosmic river that has crossed the Milky Way for hundreds of millions of years.
Astronomers say that the gigantic cluster of freshly discovered stars passes relatively close to our solar system. The cluster contains at least 4,000 stars that have regularly clustered in the night sky like a river, covering almost the entire southern sky. To be clear, the stars are not new discoveries: the fact that they are in a group is the revelation that we have here.
"Most star clusters of the galactic disk disperse quickly after birth because they do not contain enough stars to create deep gravitational potential." In other words, they do not have enough stars to create a deep gravitational potential. have not enough glue to hold them together, "said Stefan Meingast, director author of the study published today in the journal Astronomy & Astrophysics and astronomer working at the University of Vienna, Austria .
"Even in the immediate solar neighborhood, however, there are some clusters with sufficient star mass to remain bound several hundred million years ago. Thus, in principle, remnants of clusters or similar associations, of flux type, should also be part of the Milky Way disk. "
It is estimated that the stellar river was formed about a billion years ago and has already made four times around the Milky Way.
The projection of stellar flow centered around the galactic south pole. The Milky Way is curved in an arc and the red dots are the stars of the group. Image credit: Astronomy & Astrophsyics.
Researchers from the University of Vienna and Harvard University spotted the star flow by accurately mapping the 3D motion of 200 stars using data taken with the European spacecraft Gaia. The distribution and movements of the stars showed obvious signs that they were all enclosed in a clod and that they were separated by the gravitational field of the Milky Way.
Help us detect 50 neutron star collisions to be able to calculate the expansion of the universe, plead cosmoboffins
"Identifying nearby disk flows, it's like looking for the needle in a haystack," said João Alves, co-author of the article and professor of astrophysics at the University of Vienna.
"Astronomers have been watching and studying this new stream for a long time because it covers most of the night sky, but only realize now that it is there and that it is huge and very close to the Sun. Finding objects close to home is very useful, it means that they are neither too weak nor too fuzzy to allow a more detailed exploration, as astronomers dream. "
The team hopes that the study of the Sinuous Star River will allow them to better understand the mass and gravitational field of the Milky Way and help scientists determine how to obtain its stars. ®