HomeScience and ResearchSpace“Closest black hole” to Earth was actually a “vampire” star system, says...

“Closest black hole” to Earth was actually a “vampire” star system, says new study

Published on

The closest black hole to our solar system discovered in 2020 just 1000 light-years away in the HR 6819 system is actually a “vampire” two-star system in a rare and short-lived stage of evolution.

The closest black hole to Earth, located barely 1000 light-years away in the HR 6819 system, was discovered in 2020 by a team led by European Southern Observatory (ESO) researchers.

However, other researchers, including an international team based at KU Leuven in Belgium, disputed their findings. These two teams have joined forces in a paper released today to announce that there is no black hole in HR 6819, but rather a “vampire” two-star system at a unique and short-lived stage of its existence.

“Closest black hole” to Earth was actually a “vampire” star system, says new study
“Closest black hole” to Earth was actually a “vampire” star system, says new study

Both the press and scientists paid close attention to the original study on HR 6819. The astronomical community’s reaction to their finding of the black hole did not surprise Thomas Rivinius, a Chile-based ESO astronomer and the main author of that report.

“Not only is it normal, but it should be that results are scrutinised,” he says, “and a result that makes the headlines even more so.”

Rivinius and his colleagues were confident that the best explanation for the data collected with the MPG/ESO 2.2-metre telescope was that HR 6819 was a triple system, with one star orbiting a black hole every 40 days and the other star orbiting in a considerably broader orbit. However, a study led by Julia Bodensteiner, a PhD student at the KU Leuven in Belgium at the time, presented a different interpretation for the same data: HR 6819 may be a system with only two stars on a 40-day orbit and no black hole at all. This alternative scenario would need one of the stars being “stripped,” which would imply that it had lost a significant portion of its mass to the other star at some point in the past.

“We had reached the limit of the existing data, so we had to turn to a different observational strategy to decide between the two scenarios proposed by the two teams,” says lead author Abigail Frost.

Stellar Vampirism – “Closest black hole” system found to contain no black hole

The two teams collaborated to gather additional, finer data of HR 6819 using ESO’s Very Large Telescope (VLT) and Very Large Telescope Interferometer to solve the enigma (VLTI).

“The scenarios we were looking for were rather clear, very different and easily distinguishable with the right instrument,” adds Rivinius. “We agreed that there were two sources of light in the system, so the question was whether they orbit each other closely, as in the stripped-star scenario, or are far apart from each other, as in the black hole scenario.”

The astronomers employed the GRAVITY instrument on the VLTI and the Multi Unit Spectroscopic Explorer (MUSE) instrument on ESO’s VLT to distinguish between the two suggestions.

“MUSE confirmed that there was no bright companion in a wider orbit, while GRAVITY’s high spatial resolution was able to resolve two bright sources separated by only one-third of the distance between the Earth and the Sun,” adds Frost. “These data proved to be the final piece of the puzzle, and allowed us to conclude that HR 6819 is a binary system with no black hole.”  

“Our best interpretation so far is that we caught this binary system in a moment shortly after one of the stars had sucked the atmosphere off its companion star. This is a common phenomenon in close binary systems, sometimes referred to as “stellar vampirism” in the press,” explains Bodensteiner, one of the study authors. “While the donor star was stripped of some of its material, the recipient star began to spin more rapidly.”

“Catching such a post-interaction phase is extremely difficult as it is so short,” adds Frost. “This makes our findings for HR 6819 very exciting, as it presents a perfect candidate to study how this vampirism affects the evolution of massive stars, and in turn the formation of their associated phenomena including gravitational waves and violent supernova explosions.”

As for the search for black holes, the team remains optimistic. “Stellar-mass black holes remain very elusive owing to their nature,” says Rivinius. “But order-of-magnitude estimates suggest there are tens to hundreds of millions of black holes in the Milky Way alone,” Baade adds. It is just a matter of time until astronomers discover them.

Source: 10.1051/0004-6361/202143004

Image Credit: ESO

You were reading: “Closest black hole” to Earth was actually a “vampire” star system, says new study

Latest articles

Here’s How and When Mount Everest-sized ‘Devil Comet’ Can Be Seen With Naked Eye

Mount Everest sized Comet 12P/Pons-Brooks, also known as "devil comet" which is making its...

Something Fascinating Happened When a Giant Quantum Vortex was Created in Superfluid Helium

Scientists created a giant swirling vortex within superfluid helium that is chilled to the...

The Science of Middle-aged Brain and the Best Thing You Can Do to Keep it Healthy, Revealed

Middle age: It is an important period in brain aging, characterized by unique biological...

Science Shock: Salmon’s Food Choices Better at Reducing Risk of Heart Disease and Stroke

Salmon: Rich in Health Benefits, Yet May Offer Less Nutritional Value - This is...

More like this

Here’s How and When Mount Everest-sized ‘Devil Comet’ Can Be Seen With Naked Eye

Mount Everest sized Comet 12P/Pons-Brooks, also known as "devil comet" which is making its...

Something Fascinating Happened When a Giant Quantum Vortex was Created in Superfluid Helium

Scientists created a giant swirling vortex within superfluid helium that is chilled to the...

The Science of Middle-aged Brain and the Best Thing You Can Do to Keep it Healthy, Revealed

Middle age: It is an important period in brain aging, characterized by unique biological...