by In the 1930s, when the physicist and engineer Karl Jansky pointed his radio antenna towards the center of our galaxy, he detected a continuous source of radio waves. After some analysis, scientists realized that these radio waves were being emitted by something much further away from our planet the sun — but strangely enough, they were comparable in energy to the waves we get from the sun.
With this information, they began to suspect something really powerful must be lurking in the middle The Milky Way.
Later the astronomers realized that the source of these mysterious radio waves was only a supermassive black hole more than a million times more massive than our own sun We now call it Sagittarius A*. Commonly abbreviated to Score A*, the massive object essentially acts as a gravitational anchor for the entire Milky Way. Since these early observations, astronomers have come to learn quite a bit about Sgr A*; because astronomers can observe it, the black hole gives us the best chance to answer an interesting question — can a star form around black holes?
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Sgr A* is surrounded by clumps of molecular clouds — interstellar shoulders where you’ll see a star or two come to life. However, astronomers thought that the proximity of these clouds to the black hole could disrupt any stellar nursery that might be on the way, as extreme tidal and electromagnetic forces are believed to destabilize the pockets. gases that usually accumulate to form. stars.
“The combination of low average density and strong tidal forces at the [supermassive black hole] making it difficult for stars to form in the ‘standard’ way, that is to say when the dense gas clouds collapsed. They would be torn apart before being able to collapse,” astrophysicist Rosalba Perna of Stony Brook University in New York told Space.com
Later observationshowever, they mentioned the possibility that star formation may be occurring much closer to Sgr A* than we first realized.
Astrologers, for some time, were observing the stars in the vicinity of Sarsella A*, but explained that they could be present due to migration towards the black hole after first being distant clusters. The problem with this explanation, however, is that many of these newly discovered stars appear too young to have formed far away and traveled across space get to Sr A*.
Young Stars seen near Sgr A*
Led by Florian Peißker, a postdoctoral researcher at the Institute of Astrophysics of the University of Cologne, the team of astronomers identified the young stellar object X3a.
“It turns out that there is a region a few light-years away from the black hole that fulfills the conditions for star formation. This region, a ring of gas and dust, is relatively cold and protected against destructive radiation,” Peißker explained in a statement.
Surrounding Sgr A*, and other supermassive black holes for that matter, is an accretion disk of gas and dust that falls towards the black hole due to its massive gravitational pull. The separate disc covering Sgr A* extends between 5 and 30 light year from the event horizon of the black hole.
The team believes that X3a may have formed in a gaseous envelope in the outer ring of the accretion disk around Sgr A*. These gas clouds may become large enough to collapse in on themselves to create protons.
Researchers have also speculated about other possible explanations for the presence of stars near the A* Score.
“The presence of young stars around black holes has led astrophysicists to expand their views on star formation, and various theories have been developed to explain them, such as formation in a disk as a result of disruption of a molecular cloud, formation in a cluster in far after that. migrating inward and shock compression induced by a turbulent tidal event,” says Perna.
Perna recently wrote a paper which suggested that tidal disruption events (TDEs) near black holes could create the right conditions for star formation. TDEs are events where gravitational instability can be introduced into the accretion disk of a black hole, for example a star collapsing towards a black hole. These TDEs can interact with the black hole’s accretion disk in such a way that high densities of gas and dusk occur, allowing dense clumps to collapse into young stars.
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Perna explains that the evolutionary stage of that black hole is likely to affect star formation around the black holes. When a black hole is “active”, probably during its early stages when the surrounding galaxy is chaotic, it is surrounded by an accretion disk of gas and dust. This accretion disk can be a fertile ground for star formation due to the high density accretion of matter. However, now that the Milky Way is much older, things have settled down, and star formation around Sgr A* has probably slowed down from what it might have been in the past.
Although black holes remain a cosmological enigma, astronomers are learning more about how they interact with their environment to give birth to new stars and affect the evolution of their home galaxies.
