A dormant black hole with a mass at least nine times the mass of the Sun has been discovered, only 160,000 light-years from Earth, orbiting a star.
A team of researchers – known as the ‘black hole police’ because they debunked so many black hole discoveries – searched nearly 1,000 stars from the Tarantula Nebula in the constellation of Dorado before locating them.
They claim that this is the first extinct black hole to be discovered outside the Milky Way.
Stellar-mass black holes form when massive stars reach the end of their lives and collapse under the influence of their own gravity.
A black hole is described as “inert” if it is not actively devouring matter and, as a result, does not emit any light or other radiation.
This discovery has been likened to finding a “needle in a haystack”, where inert black holes are difficult to detect because they do not interact with their surroundings.
Co-author Dr Pablo Marchant of KU Leuven in Belgium said: “It’s incredible, we hardly know any dormant black holes given how commonly astronomers believe them.”
Artist’s impression of the binary system VFTS 243. The system, located in the Tarantula Nebula in the Large Magellanic Cloud, consists of a hot blue star 25 times the mass of the Sun and a black hole, which is at least nine. twice the mass of the sun
Artist’s impression of the binary system VFTS 243. The background image shows the Visible and Infrared Survey Telescope for Astronomy (VISTA) image of a portion of the Large Magellanic Cloud, indicating the region in which VFTS 243 is located. The star and black hole sizes and orbits are not close to each other.
The newly discovered black hole is located in the Large Magellanic Cloud – a satellite galaxy of the Milky Way.
The Large Magellanic Cloud orbits a hot blue star three times the size of our galaxy.
Thousands of stellar-mass black holes are believed to exist in the Milky Way and the Magellanic Clouds.
It is much smaller than the supermassive black hole 27,000 light-years from Earth that powers the Milky Way, known as Sagittarius A*.
The black hole is part of a “binary” with a bright companion star, orbiting each other in a system known as VFTS 243.
‘For more than two years, we have been searching for binary black hole systems,’ said co-author Dr. Julia Bodensteiner, of the European Southern Observatory (ESO) in Germany.
“I was very excited when I heard about VFTS 243, which in my opinion is the most compelling candidate reported to date.”
It took six years of data from ESO’s Very Large Telescope (VLT) to officially identify VFTS 243.
The FLAMES (Large Multi-element Fiber Array) scanner on the VLT allows monitoring of more than a hundred objects simultaneously.
Historically, binaries hosting stellar-mass black holes have been identified by the presence of bright X-ray emissions from the accretion disk.
The glowing accretion disk consists of gases from the atmosphere of a living star that flow toward and surround the black hole.
However, observations from NASA’s Chandra X-ray telescope revealed that VFTS 243 is faint in X-rays.
This image from the VLT Survey Telescope at ESO’s Paranal Observatory in Chile shows the Tarantula Nebula and its surroundings within the Large Magellanic Cloud. Shows star clusters, glowing gas clouds, and the scattered remnants of supernova explosions
Historically, binaries hosting stellar-mass black holes have been identified by the presence of bright X-ray emissions from the accretion disk (pictured). A glowing accretion disk consists of gases from the atmosphere of a living star that flow into and around the black hole (illustration)
The study, published today in natural astronomyalso sheds light on how black holes form from the cores of dying stars.
The star that gave rise to VFTS 243 appears to have collapsed completely, leaving no trace of a powerful supernova explosion.
Dr Shunar explained that “evidence for this ‘direct collapse’ scenario has only recently begun to emerge – but arguably our study provides one of the most direct indications.”
This has enormous implications for the origin of black hole mergers in the universe.
It took six years of data from ESO’s Very Large Telescope (pictured) to determine VFTS 243
The FLAMES instrument, mounted on the Nasmyth A platform in ESO’s Very Large Telescope. FLAMES is a high-resolution VLT spectrogram that can reach targets over a large corrected field of view. Allows to monitor more than one hundred objects simultaneously
Artist rendering of NASA’s Chandra X-ray Observatory space telescope
Despite the nickname “black hole police,” the international team of researchers actively encourages scrutiny of their work.
Lead author Dr Tomer Schnarer, from the University of Amsterdam said: ‘As a researcher who has debunked potential black holes in recent years, I was very skeptical about this discovery.
For the first time, our team has come together to report the discovery of a black hole – rather than dismiss it.
Dr. Karim El-Badri of Harvard University in Boston has been dubbed the “black hole destroyer” due to his notoriety for exposing discoveries.
Dr. Al-Badri said: When Tomer asked me to double-check his findings, I had my doubts.
But I could not find a reasonable explanation for the data that is not related to the black hole.
Of course I would expect others in the field to scrutinize our analysis carefully, and to try to develop alternative models.
“It’s a very exciting project to be involved in.”
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