Atmosphere theft in space: Why the black hole closest to Earth is just a vampire star

Status: 12:20 PM| Reading time: 3 minutes

FifthTwo years ago, an international team of astronomers reported the discovery of a black hole near the star HR 6819, about 1,000 light-years away, and so it would be the closest such object to Earth to date – thus making headlines around the world. But now sky researchers have to correct themselves: more accurate observations show that HR 6819 is a strange star – a “vampire star” – but nothing can be seen from the black hole. Scientists wrote that the misinterpretation occurred because the star is in an unusual and very recent stage of its evolution In the journal “Astronomy and Astrophysics”.

Such a process – correcting the result – is not only natural to science, but “this is exactly what it should be,” explains Thomas Rivinius of ESO’s European Southern Observatory in Chile. “The results must be critically examined by colleagues – even more so when they make headlines.” Rivinius is one of the original “discoverers” of a supposed black hole – and he’s also part of the team that has now disproved this discovery.

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The star HR 6819 is located in the southern sky in the constellation telescope and can even be seen with the naked eye under favorable conditions. Rivinius and his colleagues had to use a smaller telescope The European Southern Observatory has recorded very precise spectra of the star – that is, examining how the star’s light is distributed at different wavelengths. In this way, astronomers receive information, among other things, about the temperature and motion of the star. But the spectrum of HR 6819 was strange and inexplicable with a single star.

Finally, the researchers were able to describe their observations with a model. Accordingly, HR 6819 consists of a total of three objects, one of which should be a black hole with a mass about four times the mass of the Sun. A star about five solar masses orbits this black hole in a narrow orbit. At a much greater distance, another star orbits this near weakness, but the researchers were unable to make any statement about its mass.

Vampire vs Black Hole Scenario

This model was criticized shortly after its publication: a team led by Julia Budensteiner of the university black In Belgium the spectrum of HR 6819 can also be interpreted differently – without the presence of a black hole. Instead, the alternate model comes with two stars, one of which has yanked out part of the other’s substance, and is thus also referred to as a “vampire star”.

To determine which model is correct, both teams collaborated and made further observations with ESO’s Very Large Telescope. “Because with the right tool, it should be easy to distinguish between the two scenarios,” says Rivinius. “We agreed that there were two bright stars in the system. The question was: are they close to each other, as in the vampire scenario, or far away, as in the black hole scenario.”

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The result of the observations was clear: the images showed nothing at a great distance, but two stars approaching each other. “Our best explanation now is that we see this tight duo after the moment the ‘vampire star’ ripped its atmosphere from its mate,” Bodensteiner explains.

This process also explains the strange spectrum of the double star. While HR 6819 does not contain a black hole, it does provide astronomers with a rare opportunity to glimpse this short phase of binary star evolution. The address of the closest black hole to Earth is V723 Monocerotis, at a distance of 1,500 light-years.