Big black hole expels fast-moving star out of our galaxy for good
By AJ Siytangco
Published Nov 14, 2019 11:00 am
By EFE-EPA
A supermassive black hole has flung a fast-moving star from the center of our galaxy which is now on its way out of the Milky Way for good, a new study has discovered.
The incident occurred about five million years ago and the evicted star traveling at over six million kmph (3.7 million mph) speed is estimated to take some 100 million years to reach the intergalactic space and stay in the emptiness for all the times to come.
The mind boggling phenomenon was discovered by an international group of astronomers from Australia, Chile, the United States and the United Kingdom.
The existence of fast-moving stars was already known but it is for the first time that scientists have proven that the fast and furious astronomical bodies could be kicked out of a galaxy by black holes, the Australian National University (ANU) said in a statement on Wednesday.
“We traced this star's journey back to the center of our galaxy, which is pretty exciting," said Gary Da Costa from the ANU Research School of Astronomy and Astrophysics.
Da Costa said the star is traveling at a “record-breaking speed – 10 times faster than most stars in the Milky Way, including our Sun”.
“In astronomical terms, the star will be leaving our galaxy fairly soon and it will likely travel through the emptiness of intergalactic space for eternity," said the astronomer.
“It's great to be able to confirm a 30-year-old prediction that stars can be flung out of a galaxy by the supermassive black hole at its center.”
The astronomer said the star had been expelled by a giant black hole, Sagittarius A, located at the center of the Milky Way and with a mass equivalent to more than four million Suns.
Thomas Nordlander, another astronomer at the ANU, said supermassive black holes can eject stars by interacting with a binary stellar system, in which two stars orbit around each other.
“If such a binary system approaches a black hole too closely, the black hole can capture one of the stars into a close orbit and kick out the other at very high speed," he said.
The discovery was made by chance while a group of scientists, led by Sergey Koposov of the Carnegie Mellon University in the US, were looking for the shredded remains of small galaxies orbiting the Milky Way.
“The star is only 29,000 light years away, quite close by galactic standards, which means the team could measure its trajectory very precisely,” said Douglas Mackey, another ANU astronomer who took part in the study.
The mind boggling phenomenon was discovered by an international group of astronomers from Australia, Chile, the United States and the United Kingdom.
The existence of fast-moving stars was already known but it is for the first time that scientists have proven that the fast and furious astronomical bodies could be kicked out of a galaxy by black holes, the Australian National University (ANU) said in a statement on Wednesday.
“We traced this star's journey back to the center of our galaxy, which is pretty exciting," said Gary Da Costa from the ANU Research School of Astronomy and Astrophysics.
Da Costa said the star is traveling at a “record-breaking speed – 10 times faster than most stars in the Milky Way, including our Sun”.
“In astronomical terms, the star will be leaving our galaxy fairly soon and it will likely travel through the emptiness of intergalactic space for eternity," said the astronomer.
“It's great to be able to confirm a 30-year-old prediction that stars can be flung out of a galaxy by the supermassive black hole at its center.”
The astronomer said the star had been expelled by a giant black hole, Sagittarius A, located at the center of the Milky Way and with a mass equivalent to more than four million Suns.
Thomas Nordlander, another astronomer at the ANU, said supermassive black holes can eject stars by interacting with a binary stellar system, in which two stars orbit around each other.
“If such a binary system approaches a black hole too closely, the black hole can capture one of the stars into a close orbit and kick out the other at very high speed," he said.
The discovery was made by chance while a group of scientists, led by Sergey Koposov of the Carnegie Mellon University in the US, were looking for the shredded remains of small galaxies orbiting the Milky Way.
“The star is only 29,000 light years away, quite close by galactic standards, which means the team could measure its trajectory very precisely,” said Douglas Mackey, another ANU astronomer who took part in the study.