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The artist’s impression consists of a star with a disk around it (the “vampire” star, foreground) and a companion star with its outer part removed (background).Credit: Photo credit: ESO/L. Calzada
A groundbreaking new discovery by scientists at the University of Leeds could change the way astronomers understand some of the largest and most common stars in the universe. The paper “Gaia reveals differences in the binary nature of B and Be stars on small scales: Evidence for mass transfer driving the Be phenomenon” has been published in the journal Monthly Notices of the Royal Astronomical Society.
Research conducted by Ph.D. students Jonathan Dodd and Professor René Oudmayr of the University’s Department of Physics and Astronomy have discovered that massive Be stars, previously thought to exist primarily as double stars, are actually triple stars. They point to interesting new evidence that this may be the case.
This remarkable discovery is considered an important “test bed” for developing theories about how stars evolve more generally. Our understanding of astronomical objects (a subset of B stars) could bring about a revolution.
These Be stars are surrounded by a distinctive disk of gas, similar to the rings of Saturn in our solar system. And although Be stars have been known for about 150 years, since they were first identified by the eminent Italian astronomer Angelo Secchi in 1866, until now we have no idea how they formed. No one knew.
The consensus among astronomers so far is that the disk is formed by the rapid rotation of the Be star, which itself may be caused by the interaction of one star with another in a binary system.
triple system
“If you’ve ever seen Star Wars, the best reference point for that is that there are planets with two suns,” said Dodd, lead author of the study.
But now, by analyzing data from European Space Agency’s Gaia satellitescientists say they have found evidence that these stars actually exist in triple systems, with three bodies interacting instead of just two.
Dodd added: “We observed stars moving across the night sky over long periods of 10 years and short periods of about six months. , but if you have more than one, you’ll see a slight wobble, or in the worst case, a spiral.
“We applied this to the two groups of stars we study, B and Be stars. And, confusingly, Be stars initially had a higher proportion of companion stars than B stars. We found that it appears to be low, which is interesting because we would expect the star to be much higher.”
But lead researcher Professor Udmayr said: “The fact that we don’t find them may be because they are now too faint to detect.”
mass transfer
The researchers then looked at another dataset to look for more distant companions and found that at these larger distances, the proportion of companions was very similar between B and Be stars. discovered.
This suggests that in many cases a third star acts to bring the companion star closer to the Be star, close enough that mass can be transferred from one to the other to form the characteristic Be star disk. I could guess. This may also explain why we don’t see these friends anymore. After the “vampire” Bee stars sucked in most of their mass, they have become too small and faint to detect.
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An artist’s impression of a vampire star (left) stealing material from its victims: A new study using data from ESO’s Very Large Telescope shows that the hottest and brightest stars, known as O stars, are often found in close pairs. It became clear that Many such binary stars transfer mass from one star to another at some point. This is the kind of star vampirism depicted in this artist’s impressions.Credit: Photo credit: ESO/M. Kohnmesser/SE De Mink
This discovery could have major implications for other areas of astronomy, including our understanding of black holes, neutron stars, and gravitational wave sources.
Professor Oedmeyer said, “Currently, there is a revolution in physics centered around gravitational waves.We have only started observing these gravitational waves in the past few years, but they are caused by the merger of black holes. It turned out that there was something.”
“We know that mysterious objects such as black holes and neutron stars exist, but we don’t know much about the stars that become them. Our discovery provides clues to understanding the sources of these gravitational waves. ”
He added: “Over the past decade or so, astronomers have discovered that binaries are a very important element in the evolution of stars. We now know that binaries are even more complex than that, and triple “We’re moving towards the idea that we need to consider the stars,” he added.
“Certainly, triples have become the new binary,” Udmayer said.
For more information:
Jonathan M Dodd et al, “Gaia reveals small-scale binary differences between B and Be stars: Evidence for mass transfer driving the Be phenomenon.” Royal Astronomical Society Monthly Notices (2023). DOI: 10.1093/mnras/stad3105.upon arXiv: arxiv.org/pdf/2310.05653.pdf
Magazine information:
Royal Astronomical Society Monthly Notices