An international team of astronomers has discovered an ancient star system orbiting our Milky Way galaxy. Its peculiarity is not only its venerable antiquity, but also the fact that the system itself turned out to be the lightest in the entire history of observations.
According to Phys.org, the team conducted the study using two observatories in Hawaii: the Keck Observatory and the CFHT Telescope. The data obtained allowed us to determine the characteristics of the star system, called UMa3/U1. It turned out to be the lightest Milky Way satellite known to science. Scientists also suggest that the star system studied may be the leader in dark matter volume.
“UMa3/U1 is located in the Ursa Major constellation, where the Big Dipper is located,” says the study’s lead author, Simon Smith of the University of Victoria, “it’s in our cosmic backyard, approximately 30,000 years away.” sunlight”. /U1 had not been detected previously due to its extremely low luminosity.”
Observations have shown that the object is a small star system. There are only about 60 stars in it, but its age exceeds 10 billion years. The diameter of the system is only 10 light years. Furthermore, the UMa3/U1 object has an extremely small mass: it is 16 times the mass of the Sun, but 15 times lighter than the lightest dwarf galaxy.
“There are so few stars in UMa3/U1 that one might wonder if it is just a random group of stars. But Keck Observatory has shown that this is not the case,” says co-author Marla Geha of Yale University. “Our measurements clearly show that all stars in this group move at the same speed and appear to have similar chemical compositions.”
The full study was published in the Astrophysical Journal.
