Scientists studied the globular cluster NGC 5634, which was suspected to have previously belonged to a dwarf elliptical galaxy in Sagittarius. It turned out that the Milky Way did not actually steal this group of stars from its closest neighbor.
Globular cluster NGC 5634
Chinese astronomers used the DESI Legacy Imaging Survey of the starry sky to investigate the origin of the globular cluster NGC 5634. It is located 82,000 light years away from us in the direction of the constellation Virgo. This is a very old group of stars that were once born together.
Globular clusters are fairly large compact groups that can contain hundreds and thousands of stars and exist long enough to survive the interactions and mergers of galaxies that last for billions of years.
This was also suspected in the case of NGC 5634, as previous studies showed that it may have previously belonged to an elliptical dwarf galaxy in Sagittarius. The latter is our closest neighbor, a small system that is currently falling toward the Milky Way. The gravity of our own galaxy is gradually tearing it apart, resulting in a stream of stars.
It is not surprising that researchers assumed that NGC 5634 was also “stolen” by the Milky Way from its small neighbor at one time. And it was this version that scientists decided to test.
Research results
Analysis of DESI data allowed scientists to determine that NGC 5634 has a tidal radius of 8.35 arcminutes and a core radius of approximately 0.21 arcminutes. The age of the cluster is 12.8 billion light years.
In addition, researchers searched for potential large-scale tidal structures around NGC 5634. However, they found no evidence of anything resembling tidal tails or unexplained star clusters in this region.
In addition, scientists have refined the parameters of NGC 5634’s orbit. It turns out that they are not at all similar to those that have clusters that definitely belong to the galaxy in Sagittarius. So it never belonged to it. This does not rule out the possibility that it became part of the Milky Way during some other merger, such as Gaia-Enceladus or Helmi.
According to phys.org
