The discovery is paradoxical to say the least, since its authors are unofficially known as the “black hole police” specializing in discrediting the supposed discovery of this type of celestial objects on other repeated occasions. “For the first time, our team has come together to report on the discovery of a black hole, rather than to refute it,” says the study leader, Tom Shenar.
“We identified a needle in a haystack,” he continues. And it is that although other candidates for similar black holes have been proposed, the team claims that it is the first “dormant” stellar-mass black hole to be unambiguously detected outside our galaxy. The research findings are detailed in an article published this week in the journal Astronomy & Astrophysicsunder the title “X-ray silent black hole born with negligible kick in massive Large Magellanic Cloud binary”.
Inactive black holes, inconspicuous and hard-to-detect astronomical objects
The bone stellar mass black holes they form when massive stars reach the end of their life and collapse under their own gravity. In a binary system, a system of two stars rotating around each other, this process leaves a black hole orbiting with a bright companion star. Thus, astronomers understand that a black hole is asleep if it does not emit high levels of X-rays, which is how these black holes are usually detected. “But it’s amazing that we barely know about dormant black holes, given how common astronomers think they are,” says the study’s co-author. Paul Marchant.
The newly discovered black hole is at least 9 times the mass of our Sun and orbits a hot blue star with 25 times the mass of our star.
Dormant black holes are particularly difficult to detect because they interact little with their environment.. “For more than two years, we have been looking for this type of binary black hole system,” explains the co-author of the study, the researcher at the European Southern Observatory, Julia Bodensteiner. “I was very excited when I heard about VFTS 243, which I believe is the most compelling candidate reported to date.”
A black hole in our cosmic neighborhood
To find VFTS 243, it was necessary to observe nearly 1,000 massive stars located in the region of the Tarantula Nebula in the Large Magellanic Cloud and look for those that were likely to have black holes as companions. Identifying these companions as black holes is extremely difficult, as there are many alternative possibilities.
“As a researcher who has debunked potential black holes for the past few years, I was extremely skeptical of this discovery,” Shenar says. This skepticism was shared by the co-author of the study, Kareem El Badry, from the Harvard & Smithsonian Center for Astrophysics, which Shenar calls the “black hole destroyer”. “When Tomer asked me to double-check his findings, I had my doubts. But I couldn’t find a plausible explanation for the data that didn’t involve a black hole.“, explains El-Badry.
This discovery also gives the team unique insight into the processes that accompany the formation of black holes. Astronomers believe a stellar-mass black hole forms when the core of a dying massive star collapses, but it’s unclear whether or not this should be accompanied by a powerful supernova explosion. “The star that formed the black hole in VFTS 243 appears to have completely collapsed, no sign of a previous explosion,” says Shenar. “And our study provides one of the most direct proofs of this phenomenon to date”, he adds before specifying that the discovery could have enormous implications when it comes to explaining the origin of the black hole mergers in the cosmos.
Despite the nickname “black hole police”, the team actively encourages constant examination of the sky and hopes their work will facilitate the discovery of other stellar-mass black holes orbiting massive stars, thousands of which are expected. exist in the future. Path and in the Magellanic Clouds.
- Do you like history? Are you a photography lover? Do you want to keep up to date with the latest scientific advances? Do you like to travel? Sign up for our free National Geographic Newsletter!