A supermassive black hole ejected a superfast star from the center of the Milky Way and is now heading towards the intergalactic void, a phenomenon first observed by an international group of astronomers from Australia, Chile, the United States and the United Kingdom.
The discovery is of great importance because while it was already known about the existence of superfast stars, it had never been shown that they could be ejected through black holes, according to a statement from the Australian National University (ANU).
The star, which travels at a speed of six million kilometers per hour, will leave our galaxy – not to return – within a hundred million years, a period that in astronomical terms is quite short, explained Gary Da Costa, an astronomer at the ANU.
“It is likely that it will leave our galaxy very soon and move through the void of intergalactic space for all eternity,” said the astronomer when commenting on this eviction caused by the black hole Sagittarius A that is in the center of the Milky Way and whose mass is four million times more than that of the Sun.
The speed with which the S5-HVS1 star was moving is “ten times faster than most of the Milky Way stars, including the sun,” Da Costa said in the statement.
Thomas Nordlander, an astronomer at the ANU, commented that supermassive black holes can throw stars interacting with a binary star system, in which two stars orbit around each other.
“If such a binary system gets too close to a black hole, it can capture one of the stars in a nearby orbit and expel the other at very high speed,” said the scientist who participated in this study published in the Monthly Notices of the Royal Astronomical Society of the United Kingdom.
The discovery of this astronomical event happened by chance when the team of scientists led by Sergey Koposov of Carnegie Mellon University, in the United States, searched for the remains of small galaxies that orbit the Milky Way.
“The star is only 29,000 light years away, that is, it is quite close to galactic standards. This allowed us to measure his trajectory very accurately,” explained Dougal Mackey, another ANU astronomer who participated in the study.