New research suggests that hypervelocity stars originated in the center of the Milky Way, as a result of the interaction of a binary star and a massive black hole.
A group of astronomers from Dutch and German scientific institutions revealed that studying the motion of hypervelocity stars, which are celestial objects that travel at such high speeds that they can escape the gravity of the Milky Way, can contribute to compression. of the formation and evolution of our universe, reported the University of Leiden (Netherlands).
Previous research suggested that around 10,000 of these “speed demons” that manage to freely traverse our galaxy originated in the Large Magellanic Cloud, a dwarf star system 160,000 light-years away from Earth.
However, a recent study, published on the arXiv preprint service, raised the possibility that a number of these stellar runaways were ejected at a velocity greater than the escape velocity of the Milky Way after the gravitational encounter between a binary star. and a massive black hole at the center of our galaxy, known as Sgr A*. “We see a similar effect in the Large Magellanic Cloud, another galaxy that we have reason to believe also contains a black hole,” explained scientist Fraser Evans.
How was this conclusion reached?
The specialists indicated that they wanted to know both the origin and the acceleration force of the hypervelocity stars, so they proceeded to simulate the ejection of these celestial bodies from the galactic center, from the disintegration of the stellar binaries due to the tidal forces caused by the interaction with the Sgr A*.
Precise astrometry and radial velocity data for 2 billion stars in the Milky Way, obtained from the European Space Agency’s (ESA) Gaia space telescope, were used to carry out these tests.
In addition, information about the hypervelocity star S5-HVS1, which is a young stellar body whose mass is approximately 2.35 times greater than that of the Sun, was used. S5-HVS1, which was discovered in 2019, is located nine kiloparsec of the star king and has a speed of 1,775 kilometers per second.
In addition, information about the hypervelocity star S5-HVS1, which is a young stellar body whose mass is approximately 2.35 times greater than that of the Sun, was used. S5-HVS1, which was discovered in 2019, is located nine kiloparsec of the star king and has a speed of 1,775 kilometers per second.
“Some hypervelocity stars fly in more visible parts of space and can give us more information about where they came from, for example about the gravity of black holes or the amount of energy a supernova produces,” Evans said, concluding that these runaway stars “They have a story to tell about processes in the universe about which we know little and have much yet to discover.”
source:
https://academic.oup.com/mnras/article/491/2/2465/5612212