Madrid, 8 (European Press)
The study arose from a collaboration between a group of scientists led by Stefano Torniamenti, from the University of Padua (Italy), with Mark Gillis and Friedrich Anders, from the University of Barcelona.
The research, published in the Monthly Notices of the Royal Astronomical Society, used simulations tracking the motion and evolution of all the Hyades stars, located at a distance of about 45 parsecs, or 150 light-years, to reproduce their current state.
Open clusters are loosely-knit groups of hundreds of stars that share certain characteristics, such as age and chemical properties. The simulation results were compared with the actual positions and velocities of the Hyades stars, which are now precisely known thanks to observations made by the European Space Agency’s Gaia satellite.
“Our simulations cannot simultaneously match the mass and volume of the Hyades unless there are currently (or until recently) some black holes at the center of the cluster,” Stefano Torniamenti says in a statement.
The observed properties of the Hyades are best reproduced by simulations with two or three black holes today, although simulations in which all black holes were ejected (less than 150 million years ago, about the last quarter of the cluster’s life) There could still be a good match, because the cluster’s evolution has not been able to erase traces of its previous clusters of black holes.
The new results indicate that black holes generated by the Hyades are still within the cluster, or very close to it. This makes it the closest black hole to the Sun, much closer than the previous candidate (namely the black hole Gaia BH1, which is 480 parsecs from the Sun).
In recent years, advances made by the Gaia Space Telescope have made it possible for the first time to study the location and velocity of open star clusters in detail and to confidently identify individual stars.
“This observation helps us understand how the presence of black holes affects the evolution of star clusters and how star clusters in turn contribute to the sources of gravitational waves,” says Mark Giles, a member of the Department of Quantum Physics and Astrophysics. From the University of Barcelona where the research was conducted. “These results also give us an idea of how these mysterious objects are distributed throughout the galaxy.”
The new study is the result of a close collaboration between the University of Padua, ICUBB-IEEC, the University of Cambridge (UK), the European Southern Observatory (ESO) and National Sun Yat-sen University (China). ????????