Black hole that was closest yet found does not exist, say scientists in U-turn

Astronomers who thought they had discovered a black hole at our cosmic doorstep said they were wrong, revealing instead that they found a two-star system involving a stellar “vampire.”

The system, known as HR 6819 in the constellation Telescopium, made headlines in 2020 when researchers announced that it contained a black hole. Just 1,000 light-years from Earth, it was the closest yet found to our planet.

At the time, the team behind the work said that the presence of a black hole was necessary to make sense of the motion of two stars in the system, suggesting that one black hole and one star were orbiting each other while the second star was orbiting each other. moved in a larger orbit.

Now the researchers say they were wrong: the black hole does not exist.

Dietrich Baade, an astronomer emeritus at the European Southern Observatory (ESO) and a co-author of the paper, said only one drop of light, containing the features of two stars, was previously detected.

Since both stars are similar in brightness and age, they would normally have the same mass and would rotate relative to each other at a similar and high speed.

“Since we saw only one of the stars being rotated at high speed by a massive object, which we didn’t see, we assumed that this invisible massive object was a third body, that is, a black hole,” he said.

But other researchers disputed the idea, suggesting that the system contained only two stars, one of which had recently been stripped of mass by the second, sometimes called “vampire” stellar, making the latter much more massive.

Writing in the journal Astronomy and Astrophysics, Baade and colleagues report how groups came together to analyze recent data from ESO’s Very Large Telescope (VLT) and Very Large Telescope Interferometer (VTLI).

“Science should focus on the open questions that everyone is trying to answer, and not on who was right and who was wrong,” said Dr. Julia Bodensteiner, co-author of the ESO study that proposed the “vampire star” explanation. .

If there was indeed a black hole, the two stars would be expected to be far apart. However, in the scenario without a black hole, the stars would be expected to be much closer together.

The VLT results revealed no hint of a second star in a wide orbit. Furthermore, the data suggested that both stars contributed light captured from a single bright source, again suggesting that they were sitting close to each other.

The findings were supported by data from the VLTI, which further revealed that the two stars orbited each other.

“Because the stripped star had lost most of its mass, the second star can spin it quite easily, while its effect on the other star is just as easily overlooked,” Baade said.

While the findings rule out the idea of ​​a black hole, the researchers remain optimistic.

“The bare star is even more exciting than the black hole because it got trapped in a phase that lasts only a very small fraction of the system’s total lifetime,” Baade said.

“The excitement is not about the low chances of discovery, but about the bare star that reveals the inner part of the star. The detachment has removed the thick transparent curtain of the outer layers so that we can see much more closely where the star has generated the energy it is radiating and has synthesized new elements.”

Ref: Astronomy&Astrophysics