The stellar black hole is much closer than astrophysicists had imagined. Data from the ESA’s Gaia mission, aimed at creating the most comprehensive stellar map, revealed the existence of a star behaving anomalously. In the words of the scientists who discovered the astronomical phenomenon, the star was “wobbling” in space, as if an invisible object were pulling it, and upon further analysis, they discovered it was Gaia BH3, a black hole near Earth.
Astronomers detect a massive ‘sleeping giant’ black hole less than 2,000 light-years from Earth. A team of astronomers has identified the most massive stellar black hole yet in the Milky Way, with a mass 33 times that of the Sun, reported the European Southern Observatory (ESO) on Tuesday.
The black hole was detected in the data from the Gaia mission, a space observatory operated by the European Space Agency (ESA), which scans the sky from Earth’s orbit to create the largest and most precise three-dimensional map of the Milky Way. Data from the Extremely Large Telescope of the ESO and other ground-based observatories were used to verify the mass of the black hole, which turns out to be 33 times the mass of the Sun.
The discovery was possible because the black hole imposes a strange “wobbling” motion on the companion star orbiting it. Stellar black holes form from the collapse of massive stars, and those identified so far in the Milky Way are, on average, about 10 times more massive than the Sun. Even the next most massive stellar black hole known in our galaxy, Cygnus X-1, only reaches 21 solar masses, making this new observation exceptional.
Very Close to Earth
The ESO also highlighted that, surprisingly, this black hole is also very close to Earth, just 2,000 light-years away, in the constellation of Aquila, and is the second closest known black hole. Dubbed Gaia BH3 or BH3 for short, it was found when the team was reviewing Gaia’s observations while preparing a new data publication.
“No one expected to find a massive black hole lurking nearby and not to have been detected until now,” said Pasquale Panuzzo, a member of the Gaia collaboration and an astronomer at the Paris Observatory, part of the French National Center for Scientific Research (CNRS).
The astronomical community has previously detected equally massive black holes outside our galaxy and has theorized that they can form from the collapse of stars with compositions containing very few elements heavier than hydrogen and helium.
It is believed that these metal-poor stars lose less mass throughout their lives and therefore have more material left to produce massive black holes after their death. But until now, there was no evidence directly linking metal-poor stars to massive black holes. Star pairs tend to have similar compositions, meaning that BH3’s companion holds important clues about the star that collapsed to form this exceptional black hole, explains the ESO.
This story was written in Spanish by Perla Vallejo in Ecoosfera.
