The black hole considered until now as “the closest to Earth” was discovered in 2020 just a thousand light years from our planet. However, a group of scientists concluded that it consists of a “vampire two-star system” in a rare and short-lived evolutionary stage. The theory of the experts is that the binary system was captured shortly after one of the stars sucked the atmosphere of the other.
In this line and according to the scientific journal Astronomy & Astrophysics, they would be two luminous stars, but with very different angular separations and orbital movements. The study was carried out on the triple system HR 6819, to analyze the presence of bright sources in the range of 1 to 100 billionths of a second, which is a key diagnosis to determine its nature.
The investigation received great attention in recent months from the scientific community, which joined forces to determine the origin of the situation. It so happens that a team of experts from ESO (European Southern Observatory) discovered two years ago the alleged “black hole” in the HR 6819 system, which could have become the closest to our planet, but the results of this study were contested by various research institutions in Europe for not having the necessary foundations.
Astronomer Thomas Rivinius, lead author of the study released a few weeks ago, argued that the attention received by the first news of the “discovery of a black hole” is “normal”, however, he warned that the results of a new discovery “should be common that they be reviewed” and “even more if it reaches the headlines” around the world. According to the expert, together, they found a suitable explanation for the information they collected that HR 6819 was a triple system, with a star orbiting a black hole every 40 days and a second star in a much wider orbit.
However, research led by Julia Bodensteiner, a doctoral student at the Catholic University of Leuven, provided a different view of the discovery. In it, she pointed out that HR 6819 could also be a system with only two stars in a 40-day orbit and no black holes. It was because of this deduction that the experts pointed out that one of the stars could be “stripped” of a large part of its mass. This only meant one thing and that is that, in previous moments, this mass had been “stolen” by another star.
With these scenarios, the researchers carried out an arduous task together to reach a more accurate conclusion. “We had reached the limit of the existing data, so we had to resort to a different observation strategy to decide between the two scenarios proposed by the two teams,” said researcher Abigail Frost, from the same educational institution.
“The scenarios we were looking for were quite clear, very different and easily distinguishable with the right instrument. We agreed that there were two light sources in the system, so the question was whether they orbited each other closely, as in the stripped stars scenario, or were they far apart from each other, as in the black hole scenario? Rivinius described. Finally and after thorough investigations, the new findings of the experts determined that HR 6819 “is a binary system without a black hole.”
On the other hand, Bodensteiner argued that the binary system was captured shortly after one of the stars sucked the atmosphere from its companion. “This is a common phenomenon in close binary systems, sometimes called stellar vampirism,” she said of its ordinary name. In addition, he explained the reasons for the first conclusion reached by the experts. “As the donor star was stripped of some of its material, the recipient star began to spin faster,” he explained.
Along these lines, Frost described the discovery as something “exciting” because from this finding it could be studied how vampirism affects the evolution of massive stars. “Capturing such a post-interaction phase is extremely difficult, as it is so short,” he observed.