Using more than 500 images from the NASA/ESA Hubble Space Telescope, astronomers have found evidence of a 20,000-solar-mass black hole at the center of Earth. Omega CentauriIt is a globular cluster located in the constellation Centaurus, 5,430 parsecs (17,710 light years) from the Sun.
Omega Centauri is about 10 times more massive than other large globular clusters. Image credit: NASA / ESA / Hubble / Maximilian Häberle, MPIA.
Astronomers know that stellar-mass black holes (black holes with masses between 10 and 100 times that of the Sun) are the remnants of dying stars, and that supermassive black holes, with masses more than a million times that of the Sun, exist at the center of most galaxies.
But the universe is littered with what appear to be more mysterious types of black holes.
These intermediate-mass black holes, with masses between 100 and 10,000 times that of the Sun, are so difficult to measure that their very existence is sometimes debated.
Only a few intermediate-mass black hole candidates have been discovered so far.
Determining the black hole population is an important step towards understanding the formation of supermassive black holes in the early universe.
“Omega Centauri is a special example among globular clusters in the Milky Way,” said astronomer Maximilian Höberle of the Max Planck Institute for Astronomy and his colleagues.
“Omega Centauri is widely accepted to be the stripped core of an accreted dwarf galaxy due to its high mass, complex stellar population and kinematics.”
“These factors, combined with its proximity, make the planet a prime target in the search for intermediate-mass black holes.”
Omega Centauri is made up of about 10 million stars, making it about 10 times more massive than any other large globular cluster.
In the study, the authors measured the velocities of 1.4 million stars from images of the cluster taken by the Hubble Space Telescope.
Although most of these observations were intended for calibration of Hubble's instruments rather than for scientific use, they proved to be an ideal database for the team's research activities.
“We looked for fast-moving stars that are expected to be near concentrated masses such as black holes,” said astronomer Holger Baumgart of the University of Queensland.
“Identifying these stars was the smoking gun we needed to prove the existence of black holes, and we've done just that.”
“We found seven stars that shouldn't be there,” Dr Hebel said.
“They're moving so fast that they're likely to escape the herd and never come back.”
“The most likely explanation is that a very massive object is gravitationally tugging on these stars, keeping them near the center.”
“The only objects this massive are black holes, which have a mass at least 8,200 times that of the Sun.”
“This discovery is the most direct evidence to date for the presence of an intermediate-mass black hole at Omega Centauri,” said Dr Nadine Neumayer, an astronomer at the Max Planck Institute for Astronomy.
“This is extremely exciting because very few other black holes with similar masses are known.”
“The black hole at Omega Centauri may be the best example of an intermediate-mass black hole in our cosmic neighborhood.”
Team paper Published in the journal Nature.
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M. Heberle others2024. Stars moving at high speed around the intermediate-mass black hole at Omega Centauri. Nature 631, 285-288; Source: 10.1038/s41586-024-07511-z
Source: www.sci.news
