2024-04-17 03:05:34
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The most massive stellar black hole in the Milky Way has 33 solar masses and was found in data from the Esa mission “Gaia”. It is called Gaia BH3 and is about 2,000 light-years from Earth. (Artist’s impression) © ESO/L. Calcada
Gaia BH3, a stellar black hole, has been discovered in the Milky Way. At 33 solar masses, it is a sleeping giant that has so far remained undiscovered.
Munich – The Esa space probe “Gaia” has been mapping space for several years, and the mission regularly delivers new data that is first checked by scientists before it is published. During such a review, a research team has now made a special discovery: a team led by astronomer Pasquale Panuzzo (Observatoire de Paris) has tracked down a previously unknown black hole in our galaxy.
“Nobody expected to find a massive black hole lurking nearby that has so far remained undetected,” says Panuzzo, leader of a study conducted in the Journal Astronomy & Astrophysics published became. “You only make this kind of discovery once in your research life.”
Surprising discovery in the Milky Way: Black hole is “extremely close” to Earth
The discovery by Panuzzo and his team is something special: the research group has found the largest stellar black hole to date in the Milky Way. Gaia BH3, as the object is called, has the mass of 33 suns and is located according to one notice the European Southern Observatory (ESO) “extremely close” to Earth. There are only about 2,000 light years between the blue planet and the black hole – in astronomical dimensions that is actually very close.
Gaia BH3 is a so-called stellar black hole, which is thought to have been formed by the collapse of a massive star. The stellar black holes detected so far in the Milky Way have an average of around ten solar masses. This makes Gaia BH3 significantly larger – but not the closest black hole to Earth. This record is still held by Gaia BH1, a black hole that was also discovered in the “Gaia” data and is only 1,560 light-years from Earth.
The wobbling motion of its companion star reveals the black hole Gaia BH3
The black hole Gaia BH3, itself invisible, was discovered by the wobble of a companion star. The European Space Agency’s “Gaia” mission has been measuring this movement over several years. Additional data from other telescopes, such as ESO’s Very Large Telescope in Chile, confirmed the black hole’s mass.
The chemical composition of the companion star allows scientists to draw conclusions about the star that must have collapsed to form the black hole. The massive star is likely to have been made up of very few heavy elements or metals before its collapse – just as theory predicts. This assumes that so-called metal-poor stars lose less mass over the course of their lives and therefore more material is left over from which black holes form when they collapse.
Artist’s impression of three known stellar black holes in our Milky Way. Gaia BH1 is the closest black hole to Earth, Cygnus X-1 was the largest to date and Gaia BH3 is the largest known stellar black hole in the Milky Way as of April 2024. © ESO/M. grain knife
Study on Gaia BH3 is published early due to its importance
Elisabetta Caffau, a co-author of the study, explains: “Given the uniqueness of the discovery, we have taken the extraordinary step of publishing this work based on preliminary data ahead of the upcoming Gaia data release.” The complete “Gaia” data should not be published until the end of 2025 at the earliest.
Further study of the Gaia BH3 black hole could reveal more about the object and its history. For example, ESO’s Gravity instrument could show whether the black hole is attracting matter from its surroundings. Researchers currently suspect that Gaia BH3 is a so-called “sleeping” black hole – a sleeping giant in our Milky Way. However, compared to the supermassive black hole Sagittarius A* at the center of the Milky Way, Gaia BH3 is a dwarf: Sagittarius A* has around four million solar masses – an almost unimaginable size. (tab)
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