It is close to a black hole. The discovery of a black hole at that distance caught the attention of other people. It was the first black hole-hosting stellar system to be seen with the naked eye.
New research shows that it isn't there.
The black hole got a lot of attention when scientists published their paper. Other stellar-mass black holes interact with the matter around them. Black holes are usually discovered by Astronomers when they draw material towards themselves, heat it, and release x-rays. Astronomers discovered a black hole through interactions with its two neighbours. Astronomers thought that the discovery of a quiet black hole was the beginning of a larger phenomenon.
There must be hundreds of millions of black holes, but we don't know much about them. Thomas Rivinius, the lead author of the study, said that knowing what to look for should help us find them.
A new study dug deeper into the hole and found that it is not there. Something called stellar vampireism explains the data because a bigger star draws matter away from a smaller companion.
The system in question is called HR. The paper announced a three-star system with a black hole and two stellar companions. Researchers were looking for double-star systems. They thought that the hole affected the star's trajectory. The black hole's mass can only be deduced from the closest star's path.
The 2020 study was based on different studies over a number of years. The data from the Gaia mission played a role. The lack of x-rays from the black hole was an issue, but the study said the lack was due to the system's architecture.
The authors said in the conclusion of their paper that HR 6819 is a triple star with a BH in the innerbinary. The new study shows that there is no black hole because of the incompatibility of the spectral sequence with a simple binary.
HR 6819's absorption lines are at the center of the matter. The spectrum contained many different absorption lines.
A Be star is a type of star that behaves strangely. They are giant blue stars that are hotter and more massive than the Sun.
There was a second set of lines that were smaller and more indicative of a different type of star called a B star. Be stars spin as fast as B stars, but B stars don't. There was something odd about the lines from this B star.
The black hole conclusion enters the story here. The lines had to move back and forth because the B star had to be near something. They observed a strange sequence in HR 6819 that was incompatible with a simplebinary. The team concluded that there was a black hole at least four times larger than the Sun because they couldn't see a third star in the system.
There are three studies involved in this narrative. The study was published in 2020. The authors wrote that they were re-examining the properties of HR 6819 to see if there was a simpler explanation for it.
The analysis shows that the HR 6819 system has a stripped star and a Be star.
Rivinius was a little nervous when the studies doubted the existence of a black hole. Rivinius remembers several papers, and he thought they proposed very viable hypotheses. I started to sweat when I realized that the no-black-hole scenario was a viable hypothesis, at least as likely as ours.
The difference in our analysis is which of the lines we used to study the motion of the Be star.
We had reached the limit of the existing data, so we had to look at a different observational strategy to decide between the two scenarios proposed by the two teams.
Credit: D. Catricheo.
They knew what facility could gather the new data to solve the mystery. They knew that there were two light sources in the system, but they didn't know how close they were to each other. The VLTI was the only facility that would allow the two teams to work together. The two teams joined forces to find the true nature of the system since it made no sense to ask for the same observation twice.
The scenarios we were looking for were clear, very different and easily distinguishable with the right instrument.
MUSE confirmed that there was no bright companion in a wider orbit, while GRAVITY was able to resolve two bright sources separated by only one-third of the distance between the Earth and the Sun.
Credit was given to Frost et al.
HR 6819 is still an exciting place despite the fact that discovering a black hole only 1000 light-years away is no longer a thing. A giant star is stripping away the atmosphere of a smaller star. It isn't rare in a binary system, but it is still interesting.
The researchers were able to observe the system after the vampire star took away the donor star's atmosphere.
The best interpretation so far is that we caught this system in a moment after one of the stars had taken the atmosphere off its companion star. In the press, this phenomenon is referred to as "stellar vampireism" and is a common phenomenon in close systems.
It is very difficult to catch a post-Interaction phase as it is so short.
We conclude that HR 6819 is a system of two planets and that there is no need for a BH in this system. The authors of the new study write that HR 6819 is a perfect source for investigating the origin of Be stars.
If there had been a black hole in the system, it would have been a great scientific opportunity. An equally compelling opportunity is being replaced.
Rivinius said that he would have wanted his interpretation to be correct.
The lead author of the new paper said it was a win-win situation. We confirm the existence of the nearest stellar-mass black hole. We find this exciting and difficult to capture the evolutionary stage of a massive stellar system.
The Leuwen/ESO team has two research teams. They plan to study HR 6819 over time to understand how these systems evolve and how they work in general.
In future work, further monitoring of the system with GRAVITY will be crucial. GRAVITY is an interferometric instrument. Astronomers can use it to observe tiny details in faint objects. GRAVITY will help the research team better constrain HR 6189.
![The four Unit Telescopes that make up the ESO's Very Large Telescope, at the Paranal Observatory> Image: By ESO/H.H.Heyer [CC BY 4.0 (http://creativecommons.org/licenses/by/4.0)], via Wikimedia Commons](https://www.universetoday.com/wp-content/uploads/2018/02/1200px-Aerial_View_of_the_VLTI_with_Tunnels_Superimposed-1024x659.jpg)
They conclude that abundances of both stars could be derived.
All Rights Reserved © 2024
