Ravenous 'vampire' stars may use cosmic accomplices to help devour stellar victims
Astronomers have been aware of cosmic vampires, dead stars that hungrily strip plasma from victim stars, for some time. New research suggests that some of these cosmic fiends could have accomplices, Renfields to their Draculas, in the form of a third star in their systems, facilitating their fateful encounter.
These systems are known as cataclysmic variables, and their occupant vampire stars are white dwarfs, the type of stellar remnant that stars with masses around that of the sun leave behind when they die.
The matter stolen from their victim stellar companions by these white dwarfs piles up on the dead stars' surfaces, eventually causing them to go supernova and be obliterated. Though the endings of cataclysmic variables are fairly well understood, this research suggests at least one new origin story.
"Our results are revealing another formation channel for cataclysmic variables," California Institute of Technology (Caltech) researcher Kareem El-Badry said in a statement. "Sometimes, a lurking third star is key."
The current consensus on cataclysmic variables is that they form when two stars are brought together by a "common envelope" of gas wrapped around them. This is known as "common envelope evolution."
Eventually, one of these two stars swells up as a red giant, puffing out to up to 100 times its original size, swallowing its stellar companion. After this envelope causes these stars to spiral together, it is ejected. The red giant is now a stripped core called a white dwarf with a companion star close enough for the dead star to strip it of its outer layers.
While many stars exist in binaries, triple-star systems are also common in the universe. That prompted El-Badry, Caltech graduate student Cheyanne Shariat, and their team to wonder how this process would play out for three stars.
To investigate this, the duo turned to the European Space Agency (ESA) mission Gaia. Before its recent retirement, Gaia tracked billions of stars to collect data that is allowing scientists to construct a detailed 3D map of our cosmic backyard.
El-Badry and Shariat found 50 cataclysmic variables in triple-star systems in which two stars are closely partnered while a third orbits at a much wider distance.
These results suggested to the duo that around 10% of cataclysmic variables are found in triple-star systems, a percentage that would be lower if lurking third stars had no role in creating cataclysmic variables.
To confirm this connection, the astronomers ran 2,000 simulations of hypothetical triple-star systems, watching the gravitational interactions between the three stars as the systems evolved.
In 400 of the systems, cataclysmic variables were born without the common envelope phase occurring. In that 20% sample of the total simulations, it was the third star that "torqued" the main binary, forcing them together.
"The gravity of the third star causes the binary stars to have a super eccentric orbit, and this forces the companion star closer to the white dwarf," Shariat said. "Tidal forces dissipate energy and shrink and circularize the orbit. The star doesn't have to spiral in through the common envelope."
But that wasn't all. In 60% of the simulated systems, a common envelope phase did begin, and it was triggered by the third star.
In the remaining 20% of the simulations, the common envelope formed in the standard way without the third star contributing.
Adjusting their data to account for a more realistic population of stars, reflective of the Milky Way, and including known cataclysmic variables, the duo predicted 40% of cataclysmic variables form in triple systems.
That is four times higher than the Gaia sample. The team reasons that this is because many third stars in these systems were either too difficult to see or have been ejected from the system.
Related Stories:
— 'This is the holy grail of theoretical physics.' Is the key to quantum gravity hiding in this new way to make black holes?
— Tiny 'primordial' black holes created in the Big Bang may have rapidly grown to supermassive sizes
— A 'primordial' black hole may zoom through our solar system every decade
The simulations performed by El-Badry and Shariat also allowed the team to predict the type of triple-star systems more likely to form cataclysmic variables.
They found white dwarfs were more likely to feed on a stellar companion with the assistance of a third star when the system starts with the third star separated by over 100 times the distance between Earth and the sun.
Indeed, Gaia data did seem to show that triple systems with cataclysmic variables do indeed tend to display wider orbits.
"For the past 50 years, people were using the spiral-in common-envelope evolution model to explain cataclysmic variable formation," El-Badry concluded. "Nobody had noticed before that this was largely happening in triples!"
The team's research was published in the journal Publications of the Astronomical Society of the Pacific.
Hashtags
Try Our AI Features
Explore what Daily8 AI can do for you:
Comments
No comments yet...
Related Articles
CNN
10 minutes ago
- CNN
Betelgeuse, one of the most familiar stars in the sky, may have a hidden companion star orbiting it
Astronomers have observed what they believe to be a never-before-seen companion star orbiting Betelgeuse, a pulsating red supergiant star in the shoulder of the Orion constellation. One of the best known and most luminous stars in the night sky, Betelgeuse has long intrigued anyone who has gazed up and seen its reddish tint, which is visible to the naked eye. What has most fascinated astronomers, however, is that its brightness has been known to change over time. Now, they think the newly detected celestial object may hold the key to understanding Betelgeuse's varying brightness. From late 2019 to the beginning of 2020, Betelgeuse dimmed so sharply that astronomers thought the star was on the brink of exploding in a supernova. Since the event, called the 'Great Dimming,' teams of astronomers have determined that the star ejected a large dust cloud, which temporarily blocked some of its light from Earth's perspective. The Great Dimming led to an increased interest in solving longstanding mysteries about one of the cosmos' most observed stars — such as why its brightness appears to fluctuate regularly over a six-year cycle and has for decades. A team of astronomers has now discovered an explanation. Using an instrument on the Gemini North telescope in Hawaii, they employed an unusual imaging technique to get a glimpse of a suspected companion star, colloquially called 'Betelbuddy,' that builds on a previous theory. They suggest calling the star Siwarha, or 'her bracelet,' an Arabic name befitting the companion to Betelgeuse, which means 'Hand of the Giant.' ('Elgeuse' is also the historic Arabic name of the Orion constellation.) Understanding more about the dynamic between Betelgeuse and its companion star, also referred to as Ori B in a new study published Thursday in The Astrophysical Journal Letters, could shed light on the entwined fate of both stars. As a supergiant star, Betelgeuse is immense. Compared with our sun, it's about 700 times the radius and contains 18 times as much mass, said lead study author Steve Howell, a senior research scientist at NASA Ames Research Center in California. If our sun were replaced with Betelgeuse, the star would not only engulf Earth and all the inner planets but reach past the orbit of Jupiter, according to NASA. It also shines 7,500 to 14,000 times as bright as the sun. At 10 million years old, Betelgeuse is a fraction of the age of our sun, which is estimated to be 4.5 billion years old. However, Betelgeuse's enormousness means it has already burned through all the hydrogen at its core, causing it to expand as it nears the end of its life. Years of observations have shown that its luminosity varies periodically about every 416 days, growing fainter and then brighter. This pulsation is typical of red supergiant stars. But Betelgeuse displays an unusual pattern on top of that. 'It has been noted for decades that Betelgeuse also shows a much longer period (of variation) of about 2,170 days (about six years) which remained unexplained,' Howell wrote in an email. Two independent groups of astronomers published papers in 2024 suggesting that an unseen companion star could cause the variability. The Hubble Space Telescope and NASA's Chandra X-Ray Observatory, however, could see no evidence of such a star. Betelgeuse's size and brightness have posed challenges to attempts to spot a companion. To see both Betelgeuse and its companion, an image has to be both high-resolution and high-contrast, said Jared Goldberg, a research fellow at the Flatiron Institute's Center for Computational Astrophysics. Goldberg authored a November study suggesting Betelgeuse may have a companion star, but he was not involved with the new research. 'Normally, the Earth's atmosphere makes it hard to do this for the same reason that stars twinkle — the moving gas in the atmosphere scatters the starlight around,' Goldberg said. Howell's team decided to use a speckle imager called 'Alopeke, which means 'fox' in Hawaiian, to search for the companion. 'Speckle imaging is a technique that obtained many thousands of very short exposures of an astronomical object,' Howell said. 'These images are so short that they do not look like stars or galaxies at all, but a blob of 'speckles.'' The speckles are due to distortions from Earth's atmosphere. The thousands of brief images are processed in a way that removes the atmospheric blurring, resulting in a high-resolution telescope image, Howell said. When members of Howell's team observed Betelgeuse during the Great Dimming in 2020, they didn't see anything; the companion was likely obscured behind Betelgeuse, according to Goldberg. But in December, they spied a faint blue glow exactly where Goldberg's research — as well as another study authored by Morgan MacLeod at the Harvard-Smithsonian Center for Astrophysics — predicted the companion would be. The speckle imaging revealed a young, bluish star that isn't burning hydrogen at its core yet and only has a mass of 1.5 times that of the sun. The companion star's faintness — four-tenths of one percent as bright as Betelgeuse — is just one reason it's been hard to spot, Howell said. The other is the stars' proximity to one another — only about four times the distance between Earth and the sun separates them. On average, the Earth is about 93 million miles (150 million kilometers) away from the sun. The thing that allows the companion star to be seen, said Goldberg, is that it is a different hue than Betelgeuse. 'If the two headlights on a car represent the two stars, our view from Earth to Betelgeuse and its companion would be the same as trying to separate the two car headlights with your eye from a distance of 50,000 miles,' Howell said. 'Our observations were aided by the fact that we can directly observe Betelgeuse using very short exposures (14 milliseconds each) so as to not saturate our cameras and the large mirror size of Gemini (8 meters) allows us to obtain very high angular resolutions in images of the sky, enough resolution to separate the two stars.' It's the first time a stellar companion has been detected orbiting a supergiant star so closely, the study authors said. 'I was surprised that the companion was so obvious immediately after our data was processed,' Howell said. 'I was thinking it'd be hard to find, but boom, it was right there.' MacLeod, a postdoctoral fellow in theoretical astrophysics and member of the Institute for Theory and Computation at the Harvard-Smithsonian Center for Astrophysics, worked on research published in December that collected historical measurements of Betelgeuse's radial velocity, or motion toward or away from Earth, that began around 1896 on photographic glass plates. The team saw a repeating six-year pattern consistent with the tug of a smaller, orbiting companion star, MacLeod said. 'Putting these lines of evidence, collected from a century of astronomical measurements, together let us predict right where a companion 'should be' if it were real,' he said. 'But we hadn't seen it directly. Howell and his team made a pioneering observation in order to be able to make this initial detection.' MacLeod, who was not involved with the new study, calls its finding 'an amazing result … that shows that even the best-studied stars in our night sky have mysteries to reveal.' 'Because this was such a challenging detection to make, the observations are on the very edge of detection,' MacLeod said. 'What pushed this over the edge is that the star appeared just where we expected when we pulled together the predictions of a century's worth of astronomers.' While the discovery of the companion aligns with Goldberg's research predictions, future observations are still needed to confirm the detection. Speckle imaging is a hard measurement to make and isn't always accurate, Goldberg said. Given that the star was discovered near the limits of the instrument, its presence is probable but 'not yet a slam dunk,' said Edward Guinan, professor of astronomy and astrophysics at Villanova University in Pennsylvania. Guinan has studied Betelgeuse but was not involved in the new research. However, seeing the companion star track along its proposed six-year orbit would represent a definitive detection of the companion, Guinan said. 'Currently, we think the companion is moving away from us, and going behind Betelgeuse. So there is a clear path to confirm the new study's results: Look again when we expect the companion to be fully behind Betelgeuse, and it will be gone. Look once more when it should be coming back around on the other side, and it should be there,' Goldberg said. A new opportunity to confirm the companion's presence with telescopes will occur in November 2027 when the star would be at its farthest distance from Betelgeuse, making it easier to spot. Like MacLeod's team, Goldberg and his colleagues also determined that Betelgeuse wobbles toward and away from Earth within the same six-year period due to the presence of a stellar companion. Still, questions remain about how exactly a companion star is contributing to Betelgeuse's six-year variability, which appears to be connected to changes in dust around the star, Goldberg said. 'The dimmer phase happens when the companion is behind Betelgeuse, and the brighter phase is when the companion is in front of Betelgeuse,' Goldberg said by email. 'This means it's the opposite of an eclipse, so it seems most likely that Betelgeuse is producing its own dust and the companion is shaping it, rather than dragging it along.' About 30% of pulsating red giant and supergiant stars show the same type of variability, and if that means a companion is present, 'then many more stars harbor these little friends,' Goldberg added. 'Understanding this stellar pair can help us understand the population of things like it. And understanding that population will teach us about star and planet formation in systems that are otherwise extremely hard to observe.' Meanwhile, astronomers still wonder when Betelgeuse will explode, a catastrophic event that has been anticipated since the Great Dimming. While Betelgeuse and its companion star were likely born at the same time, the companion is still forming as a normal star, Howell said. But companion's close orbit, within the outer layers of Betelgeuse's atmosphere, will be its doom, he said. One of two things will happen. The companion star's orbit may cause it to drift slowly closer and plunge into Betelgeuse in about 10,000 years. 'At that point Betelgeuse and its companion will enter into an eternal hug,' Goldberg said. 'If we can get decades of precise direct observations, we might be able to directly test that prediction by seeing if the orbit is shrinking, and if so how quickly.' But if Betelgeuse explodes before that — 'maybe tomorrow, maybe in 100 years' — then the companion star will be destroyed in the supernova, Howell said. 'The future is not good for either star.' Sign up for CNN's Wonder Theory science newsletter. Explore the universe with news on fascinating discoveries, scientific advancements and more.
CNN
17 minutes ago
- CNN
Betelgeuse, one of the most familiar stars in the sky, may have a hidden companion star orbiting it
Astronomers have observed what they believe to be a never-before-seen companion star orbiting Betelgeuse, a pulsating red supergiant star in the shoulder of the Orion constellation. One of the best known and most luminous stars in the night sky, Betelgeuse has long intrigued anyone who has gazed up and seen its reddish tint, which is visible to the naked eye. What has most fascinated astronomers, however, is that its brightness has been known to change over time. Now, they think the newly detected celestial object may hold the key to understanding Betelgeuse's varying brightness. From late 2019 to the beginning of 2020, Betelgeuse dimmed so sharply that astronomers thought the star was on the brink of exploding in a supernova. Since the event, called the 'Great Dimming,' teams of astronomers have determined that the star ejected a large dust cloud, which temporarily blocked some of its light from Earth's perspective. The Great Dimming led to an increased interest in solving longstanding mysteries about one of the cosmos' most observed stars — such as why its brightness appears to fluctuate regularly over a six-year cycle and has for decades. A team of astronomers has now discovered an explanation. Using an instrument on the Gemini North telescope in Hawaii, they employed an unusual imaging technique to get a glimpse of a suspected companion star, colloquially called 'Betelbuddy,' that builds on a previous theory. They suggest calling the star Siwarha, or 'her bracelet,' an Arabic name befitting the companion to Betelgeuse, which means 'Hand of the Giant.' ('Elgeuse' is also the historic Arabic name of the Orion constellation.) Understanding more about the dynamic between Betelgeuse and its companion star, also referred to as Ori B in a new study published Thursday in The Astrophysical Journal Letters, could shed light on the entwined fate of both stars. As a supergiant star, Betelgeuse is immense. Compared with our sun, it's about 700 times the radius and contains 18 times as much mass, said lead study author Steve Howell, a senior research scientist at NASA Ames Research Center in California. If our sun were replaced with Betelgeuse, the star would not only engulf Earth and all the inner planets but reach past the orbit of Jupiter, according to NASA. It also shines 7,500 to 14,000 times as bright as the sun. At 10 million years old, Betelgeuse is a fraction of the age of our sun, which is estimated to be 4.5 billion years old. However, Betelgeuse's enormousness means it has already burned through all the hydrogen at its core, causing it to expand as it nears the end of its life. Years of observations have shown that its luminosity varies periodically about every 416 days, growing fainter and then brighter. This pulsation is typical of red supergiant stars. But Betelgeuse displays an unusual pattern on top of that. 'It has been noted for decades that Betelgeuse also shows a much longer period (of variation) of about 2,170 days (about six years) which remained unexplained,' Howell wrote in an email. Two independent groups of astronomers published papers in 2024 suggesting that an unseen companion star could cause the variability. The Hubble Space Telescope and NASA's Chandra X-Ray Observatory, however, could see no evidence of such a star. Betelgeuse's size and brightness have posed challenges to attempts to spot a companion. To see both Betelgeuse and its companion, an image has to be both high-resolution and high-contrast, said Jared Goldberg, a research fellow at the Flatiron Institute's Center for Computational Astrophysics. Goldberg authored a November study suggesting Betelgeuse may have a companion star, but he was not involved with the new research. 'Normally, the Earth's atmosphere makes it hard to do this for the same reason that stars twinkle — the moving gas in the atmosphere scatters the starlight around,' Goldberg said. Howell's team decided to use a speckle imager called 'Alopeke, which means 'fox' in Hawaiian, to search for the companion. 'Speckle imaging is a technique that obtained many thousands of very short exposures of an astronomical object,' Howell said. 'These images are so short that they do not look like stars or galaxies at all, but a blob of 'speckles.'' The speckles are due to distortions from Earth's atmosphere. The thousands of brief images are processed in a way that removes the atmospheric blurring, resulting in a high-resolution telescope image, Howell said. When members of Howell's team observed Betelgeuse during the Great Dimming in 2020, they didn't see anything; the companion was likely obscured behind Betelgeuse, according to Goldberg. But in December, they spied a faint blue glow exactly where Goldberg's research — as well as another study authored by Morgan MacLeod at the Harvard-Smithsonian Center for Astrophysics — predicted the companion would be. The speckle imaging revealed a young, bluish star that isn't burning hydrogen at its core yet and only has a mass of 1.5 times that of the sun. The companion star's faintness — four-tenths of one percent as bright as Betelgeuse — is just one reason it's been hard to spot, Howell said. The other is the stars' proximity to one another — only about four times the distance between Earth and the sun separates them. On average, the Earth is about 93 million miles (150 million kilometers) away from the sun. The thing that allows the companion star to be seen, said Goldberg, is that it is a different hue than Betelgeuse. 'If the two headlights on a car represent the two stars, our view from Earth to Betelgeuse and its companion would be the same as trying to separate the two car headlights with your eye from a distance of 50,000 miles,' Howell said. 'Our observations were aided by the fact that we can directly observe Betelgeuse using very short exposures (14 milliseconds each) so as to not saturate our cameras and the large mirror size of Gemini (8 meters) allows us to obtain very high angular resolutions in images of the sky, enough resolution to separate the two stars.' It's the first time a stellar companion has been detected orbiting a supergiant star so closely, the study authors said. 'I was surprised that the companion was so obvious immediately after our data was processed,' Howell said. 'I was thinking it'd be hard to find, but boom, it was right there.' MacLeod, a postdoctoral fellow in theoretical astrophysics and member of the Institute for Theory and Computation at the Harvard-Smithsonian Center for Astrophysics, worked on research published in December that collected historical measurements of Betelgeuse's radial velocity, or motion toward or away from Earth, that began around 1896 on photographic glass plates. The team saw a repeating six-year pattern consistent with the tug of a smaller, orbiting companion star, MacLeod said. 'Putting these lines of evidence, collected from a century of astronomical measurements, together let us predict right where a companion 'should be' if it were real,' he said. 'But we hadn't seen it directly. Howell and his team made a pioneering observation in order to be able to make this initial detection.' MacLeod, who was not involved with the new study, calls its finding 'an amazing result … that shows that even the best-studied stars in our night sky have mysteries to reveal.' 'Because this was such a challenging detection to make, the observations are on the very edge of detection,' MacLeod said. 'What pushed this over the edge is that the star appeared just where we expected when we pulled together the predictions of a century's worth of astronomers.' While the discovery of the companion aligns with Goldberg's research predictions, future observations are still needed to confirm the detection. Speckle imaging is a hard measurement to make and isn't always accurate, Goldberg said. Given that the star was discovered near the limits of the instrument, its presence is probable but 'not yet a slam dunk,' said Edward Guinan, professor of astronomy and astrophysics at Villanova University in Pennsylvania. Guinan has studied Betelgeuse but was not involved in the new research. However, seeing the companion star track along its proposed six-year orbit would represent a definitive detection of the companion, Guinan said. 'Currently, we think the companion is moving away from us, and going behind Betelgeuse. So there is a clear path to confirm the new study's results: Look again when we expect the companion to be fully behind Betelgeuse, and it will be gone. Look once more when it should be coming back around on the other side, and it should be there,' Goldberg said. A new opportunity to confirm the companion's presence with telescopes will occur in November 2027 when the star would be at its farthest distance from Betelgeuse, making it easier to spot. Like MacLeod's team, Goldberg and his colleagues also determined that Betelgeuse wobbles toward and away from Earth within the same six-year period due to the presence of a stellar companion. Still, questions remain about how exactly a companion star is contributing to Betelgeuse's six-year variability, which appears to be connected to changes in dust around the star, Goldberg said. 'The dimmer phase happens when the companion is behind Betelgeuse, and the brighter phase is when the companion is in front of Betelgeuse,' Goldberg said by email. 'This means it's the opposite of an eclipse, so it seems most likely that Betelgeuse is producing its own dust and the companion is shaping it, rather than dragging it along.' About 30% of pulsating red giant and supergiant stars show the same type of variability, and if that means a companion is present, 'then many more stars harbor these little friends,' Goldberg added. 'Understanding this stellar pair can help us understand the population of things like it. And understanding that population will teach us about star and planet formation in systems that are otherwise extremely hard to observe.' Meanwhile, astronomers still wonder when Betelgeuse will explode, a catastrophic event that has been anticipated since the Great Dimming. While Betelgeuse and its companion star were likely born at the same time, the companion is still forming as a normal star, Howell said. But companion's close orbit, within the outer layers of Betelgeuse's atmosphere, will be its doom, he said. One of two things will happen. The companion star's orbit may cause it to drift slowly closer and plunge into Betelgeuse in about 10,000 years. 'At that point Betelgeuse and its companion will enter into an eternal hug,' Goldberg said. 'If we can get decades of precise direct observations, we might be able to directly test that prediction by seeing if the orbit is shrinking, and if so how quickly.' But if Betelgeuse explodes before that — 'maybe tomorrow, maybe in 100 years' — then the companion star will be destroyed in the supernova, Howell said. 'The future is not good for either star.' Sign up for CNN's Wonder Theory science newsletter. Explore the universe with news on fascinating discoveries, scientific advancements and more.
Yahoo
27 minutes ago
- Yahoo
Scientists Find Evidence That Original Life on Earth Was Assembled From Material in Space
The molecules that form the building blocks to life may be far more common in space than once thought, according to researchers from the Max Planck Institute. Their work, published in The Astrophysical Journal, reports the detection of over a dozen types of complex organic molecules swimming closely around a protostar in the constellation Orion, suggesting that the chemicals can survive the violent processes that give birth to stars and thus may abound in space, instead of having to wait for a planet with the right conditions to form them. Two of the most notable organic molecules detected in the system — tentatively, the astronomers stress — are ethylene glycol and glycolonitrile. Both are precursors of the nucleic acids that form DNA and RNA. "Our finding points to a straight line of chemical enrichment and increasing complexity between interstellar clouds and fully evolved planetary systems," lead author Abubakar Fadul, an astronomer at the Max Planck Institute, said in a statement about the work. And thus, quoting the researchers' statement: "this suggests that the seeds of life are assembled in space and are widespread." Until now, the assumption has been that most organic molecules would be destroyed when a star system is born from a chilly cloud of collapsing gas called an interstellar cloud. When this happens, the protostar undergoes a violent, tumultuous change, blasting out damaging radiation that heats the surrounding gas while pummeling it with powerful shockwaves. This leaves behind a protoplanetary disk that can eventually form little worlds in the star's orbit. But in the process, this was also believed to "reset" all the progress that'd been made towards seeding the system with chemical building blocks, which wouldn't start again until the right planet with the ideal conditions came along. "Now it appears the opposite is true," study co-author Kamber Schwarz, a fellow astronomer at MPI, said in a statement about the work. "Our results suggest that protoplanetary disks inherit complex molecules from earlier stages, and the formation of complex molecules can continue during the protoplanetary disk stage." Complex organic molecules are difficult to detect because they're typically trapped in shards called icy dust grains, where they first formed. But in the V883 system, the star is still blasting bursts of radiation into space as it feeds on the leftover gas in its disk. "These outbursts are strong enough to heat the surrounding disk as far as otherwise icy environments, releasing the chemicals we have detected," Fadul said. Once liberated, the gases quickly heat up and produce emissions that astronomers can see. The researchers spotted them, fortuitously, using the Atacama Large Millimeter/submillimeter Array (ALMA), a huge radio telescope in Chile made of 66 separate antennas working in tandem. Poetically, it appears that a young star's destructive tendencies are freeing the seeds of life to roam space. If the precursors to life's building blocks can survive a system's violent formation, that means their chemical evolution can start way before planet formation begins. In short, it looks like life's building blocks can form in space, and may be rife throughout the cosmos. Follow-up observations will need to confirm the detections, but the results have the researchers buzzing. "Perhaps we also need to look at other regions of the electromagnetic spectrum to find even more evolved molecules," Fadul said. "Who knows what else we might discover?" More on astronomy: Hubble Snaps Photos of Interstellar Invader
