Latest news with #ZTF
Yahoo
13-06-2025
- Science
- Yahoo
Missing link star? Why this 'teenage vampire' white dwarf has scientists so excited
When you buy through links on our articles, Future and its syndication partners may earn a commission. Astronomers have discovered the "missing link" connecting the death of sunlike stars to the birth of white dwarf stellar remnants, in the form of a "teenage vampire" white dwarf. This vampire isn't interested in the blood that runs through your veins, though. The white dwarf in question, designated Gaia22ayj and located around 8,150 light-years from Earth, is ravenously feeding on stellar plasma from a companion star. The team that made this discovery observed the white dwarf using the Zwicky Transient Facility (ZTF) at the Palomar Observatory in California. The researchers scanned the night sky over the Northern Hemisphere, hunting "transients" — astronomical bodies undergoing rapid change. Gaia22ayj originally attracted the attention of astronomers with its rapidly pulsing signal, which led to it being classified as a detached double white dwarf binary — two white dwarf stars orbiting each other. However, this theory didn't quite match further observations of Gaia22ayj, which revealed it to be one of the most extreme pulsating objects ever seen, increasing in brightness by 700% over just a 2-minute span. That's because Gaia22ayj is actually a white dwarf feeding on a companion star, with this binary in a rare and short-lived phase of its life (or should that be death). Stars die after they use up the fuel needed for nuclear fusion. What kind of death, and afterlife, they experience depends on their mass. Stars with masses above eight times that of the sun die in violent supernova explosions and then become either highly dense neutron stars or black holes. Stars with masses closer to that of the sun don't "go nova," instead undergoing more muted transformations into white dwarfs. Our own sun will experience this latter transformation in around six billion years after shedding most of its mass during a swollen red giant phase, eventually sputtering out as a smoldering stellar ember. However, around half of all stars with masses similar to that of the sun have a binary companion star. And, if their companion stars get too close, white dwarfs can get a second burst of life by stripping them of stellar material. That vampiric mass transfer process is exactly what seems to be happening between the white dwarf of Gaia22ayj and its companion star. Gaia22ayj initially confused astronomers. The way that its light intensity varied over time — its light curve— made no sense for a detached double white dwarf binary. This led Tony Rodriguez, a graduate student in the California Institute of Technology's ZTF Stellar Group, to question why the light curve would take the shape it did. Gathering more data, Rodriguez and colleagues realized that Gaia22ayj is likely a white dwarf orbited by a "normal" low-mass star, not a second white dwarf. And they further determined that Gaia22ayj is highly magnetic, with its white dwarf component spinning at a rapid rate. This reminded them of a white dwarf pulsar, a highly magnetic dead star that sweeps electromagnetic radiation across the universe as it spins, like a cosmic lighthouse. However, the vampiric feeding process found in Gaia22ayj isn't something usually associated with white dwarf pulsars. The team eventually concluded that Gaia22ayj is a missing link in the life cycle of white dwarf pulsars, a rare and short-lived early phase of these objects. "We have already seen two infant systems, white dwarf stars in a binary system whose rapid spin builds up a strong magnetic field. And we had seen lots of adult star systems where the white dwarf star was spinning very slowly," Rodriguez said in a statement. "But this was the first star we've seen that is right in the middle of its 'teenage' phase, when it has already established a strong magnetic field and is just beginning to funnel matter from the companion star onto itself," he added. "We have never before caught a system in the act of spinning so rapidly but also slowing down dramatically, all while gaining mass from its companion." This discovery is even more exciting because this phase lasts for just around 40 million years. That might sound like an incredibly long period of time, but it's relatively short when considering that stars like the sun live for around 10 billion years before they even transform into white dwarfs. Thus, this "teenage phase" accounts for just 0.4% of a star's lifetime. For context, if the star were an average human, this teenage phase would last just around 107 days. Hardly enough time to paint your bedroom black. Related Stories: — Puffy white dwarfs could shed light on mysterious dark matter. Here's how. — White dwarfs are 'heavy metal' zombie stars endlessly cannibalizing their dead planetary systems — 'Daredevil' white dwarf star could be closest-known object to a weird black hole "The data taken at the W. M. Keck Observatory provided firm evidence that this system had a strong magnetic field and was funneling matter onto the white dwarf," Rodriguez said. "Additional data from the unique instruments available at Palomar Observatory showed that this system is, remarkably, slowing down." The team's research was published in February in the journal Publications of the Astronomical Society of the Pacific.
Yahoo
05-06-2025
- Science
- Yahoo
Astronomers discover most powerful cosmic explosions since the Big Bang
When you buy through links on our articles, Future and its syndication partners may earn a commission. Astronomers have discovered the most powerful cosmic explosions since the Big Bang, naming them "extreme nuclear transients." These incredibly energetic explosions occur when stars with masses at least three times greater than that of the sun are torn apart by supermassive black holes. While such events have been witnessed before, astronomers say some of the ones recently discovered are powerful enough to be classified as a new phenomenon: extreme nuclear transients (ENTs). "We've observed stars getting ripped apart as tidal disruption events for over a decade, but these ENTs are different beasts, reaching brightnesses nearly ten times more than what we typically see," said Jason Hinkle, a researcher at the University of Hawaii's Institute for Astronomy (IfA) who led a study on these events, in a statement. "When I saw these smooth, long-lived flares from the centers of distant galaxies, I knew we were looking at something unusual." Hinkle discovered the existence of these ENTs while combing through data gathered on long-lasting flares originating from galactic centers. Two flares caught Hinkle's eye, recorded by the European Space Agency's Gaia spacecraft in 2016 and 2018, respectively. A third event discovered in 2020 by the Zwicky Transient Facility (ZTF) appeared similar to the two phenomena discovered by Gaia, which gave researchers clues that these belonged to a new class of extreme cosmic explosions. That's because these events appeared to release far more energy than other known star explosions, or supernovas, and seemed to last much longer. These explosions also differed from tidal disruption events (TDEs), which are massive releases of energy that occur when extreme gravitational forces around black holes rip stars apart, flinging much of their mass outward into space. But TDEs typically last only a matter of hours; the events studied by Hinkle and other researchers appeared to last much longer. "Not only are ENTs far brighter than normal tidal disruption events, but they remain luminous for years, far surpassing the energy output of even the brightest known supernova explosions," Hinkle said in the statement. One of these ENTs, which astronomers have named Gaia18cdj, released over 25 times more energy than the most powerful supernova ever discovered, more than the amount of energy that would be released by 100 suns throughout their entire lifetime. RELATED STORIES: — The most powerful explosions in the universe could reveal where gold comes from — 'Shocking' nova explosion of dead star was 100 times brighter than the sun — Astronomers discover black hole ripping a star apart inside a galactic collision. 'It is a peculiar event' Aside from being the most powerful known explosions in the universe, ENTs can help astronomers learn more about monster black holes in faraway galaxies. That's because the incredible brightness of these events means they can be seen across vast distances, according to IfA's Benjamin Shappee, who co-authored the study. "By observing these prolonged flares, we gain insights into black hole growth when the universe was half its current age and galaxies were busy places — forming stars and feeding their supermassive black holes 10 times more vigorously than they do today," Shappee said in the statement. A study on this discovery was published June 4 in the journal Science Advances.
Yahoo
31-05-2025
- General
- Yahoo
Astronomers discover black hole ripping a star apart inside a galactic collision. 'It is a peculiar event'
When you buy through links on our articles, Future and its syndication partners may earn a commission. Astronomers have taken a detailed look at a rare and incredibly violent cosmic event resulting from an unfortunate star venturing too close to a supermassive black hole. The team behind the research hopes it could reveal more about how such events, dubbed "tidal disruption events" or "TDEs," influence the evolution of their host brutal battles between stellar bodies and the immense gravity of black holes with masses millions or even billions of times that of the sun result in stars being shredded and fed to the black holes. This cosmic cannibalism causes blasts of light that can outshine the combined light of every star in the host galaxy of the TDE, alerting scientists to a gory stellar death. This particular TDE has been designated AT 2022wtn, and occurred in a galaxy located around 700 million light-years away. This galaxy is in the early stages of merging with one of its galactic neighbors. The galaxy that hosts the TDE is known as SDSSJ232323.79+104107.7, and it is the smaller of the two colliding galaxies. The other galaxy mixed up in this merger is at least ten times larger than SDSSJ232323.79+104107.7. It is thought that the two galaxies in this merging system have already made a close pass to one other. This represents just the second time that a TDE has been detected in interacting galaxies. That's despite a prevailing theory that the early stages of mergers create the kind of conditions that favor these brutal occurrences. AT 2022wtn was first brought to the attention of astronomers at the Zwicky Transient Facility (ZTF), with further investigation in wavelengths of light ranging from radio to infrared and even X-rays, which revealed its nature as a TDE. The astronomers were able to determine that the black hole involved in this TDE has a mass equal to around 1 million suns, while its stellar meal is a low-mass star. However, despite clearly presenting itself as an example of a supermassive black hole ripping apart a star, there are some unusual aspects of AT 2022wtn that set it apart from other TDEs. "It is a peculiar event. Its light curve is characterized by a plateau in the phase of maximum brightness, lasting about 30 days, accompanied by a sharp drop in temperature and a spectral sequence that shows the development of two emission lines corresponding to the wavelengths of helium and nitrogen," team leader and National Institute for Astrophysics (INAF) Francesca Onori said in a statement. "Something that we had never observed with such clarity." Like all TDEs, AT 2022wtn would have begun when a doomed star's orbit brought it too close to the central supermassive black hole at the heart of its host galaxy. This results in the immense gravitational influence of the black hole generating immense tidal forces within the star. These forces squash the star horizontally while stretching it vertically, a process colorfully known as "spaghettification."Some of the resulting stellar wreckage winds around the destructive supermassive black hole like actual spaghetti around a fork, forming a whirling flattened cloud of plasma called an accretion disk. Not all of the material from the wrecked star falls around the black hole and eventually into its maw, however. A great deal of stellar matter is blasted out as powerful, high-speed outflows or jets. In the case of AT 2022wtn, these outflows created a short, bright radio emission from the TDE and extreme changes in the velocity of light-emitting elements around the also indicated that the star was completely destroyed as a result of this TDE and that, in addition to an accretion disk, the cosmic cannibalistic event created an expanding spherical "bubble" of expelled gas. Related Stories: — Black hole announces itself to astronomers by violently ripping apart a star — Massive star's gory 'death by black hole' is the biggest and brightest event of its kind — Star escapes ravenous supermassive black hole, leaving behind its stellar partner "We found clear traces of the dynamics of the surrounding material also in some emission lines which show characteristics compatible with a fast propagation towards the outside," Onori said. "Thanks to our monitoring campaign, we were able to propose an interpretation of the origin of the observed radiation: AT2022wtn gave rise to a rapid formation of the disk around the black hole and the subsequent expulsion of part of the stellar matter. "This result is particularly relevant, since the source of visible light and the physical conditions of the region from which it comes, in TDEs, are still under study."The team's research was published on May 23 in the journal Monthly Notices of the Royal Astronomical Society.
Time of India
30-05-2025
- Science
- Time of India
Astronomers witness supermassive black hole tear star apart during violent galactic collision—here's what exactly happened in this rare tidal disruption event
Black hole rips apart star in rare galactic collision: Astronomers witness violent tidal disruption event- A supermassive black hole ripping a star apart during a galaxy merger has given astronomers a rare and violent spectacle to study—one that could unlock new insights into how black holes influence their galaxies. This cosmic event, called a tidal disruption event (TDE), happened about 700 million light-years from Earth in a merging pair of galaxies. The event, named AT 2022wtn, is only the second TDE ever seen in interacting galaxies, making it an extraordinary discovery. Scientists say it sheds light—quite literally—on how massive black holes feed, evolve, and possibly impact galactic development. What exactly is a tidal disruption event and why is AT 2022wtn so rare? A tidal disruption event occurs when a star strays too close to a supermassive black hole—an object millions or even billions of times heavier than the Sun. The black hole's gravitational pull is so intense that it rips the star apart, stretching and squeezing it in a process astronomers call spaghettification. by Taboola by Taboola Sponsored Links Sponsored Links Promoted Links Promoted Links You May Like Giao dịch vàng CFDs với sàn môi giới tin cậy IC Markets Tìm hiểu thêm Undo In the case of AT 2022wtn, this violent dismemberment took place in a galaxy called SDSSJ232323.79+104107.7. This galaxy is currently colliding with a larger neighboring galaxy, at least ten times its size, in the early stages of a galactic merger. The merging process is believed to stir up activity near black holes, possibly triggering TDEs like this one. The discovery of AT 2022wtn is crucial because, although galaxy mergers are common, seeing a TDE in one is extremely rare. That's what makes this observation so special. Live Events How did astronomers find out about this cosmic disaster? The TDE was first spotted by the Zwicky Transient Facility (ZTF), which scans the sky for sudden bursts of light and unusual activity. From there, teams across the globe dug deeper, observing the event across the entire spectrum of light—from radio waves to X-rays. The black hole at the center of this event is estimated to have a mass around 1 million times that of the Sun, and the unlucky star it consumed was a low-mass star. Researchers saw a massive burst of light when the star was torn apart, which temporarily outshone the entire galaxy it lived in. What makes AT 2022wtn different from other star-eating events? According to Francesca Onori from Italy's National Institute for Astrophysics (INAF), this event showed features never seen this clearly before. She called it 'a peculiar event' and noted that its light curve stayed at peak brightness for about 30 days—a long time in TDE terms. During that time, the temperature dropped sharply, and scientists detected specific emission lines in the light from the event—namely helium and nitrogen. This suggests very complex chemical activity and possibly a rapid formation of an accretion disk, a spinning cloud of material forming around the black hole from the remains of the star. Onori added, 'We found clear traces of the dynamics of the surrounding material,' showing that stellar debris was being pushed outward rapidly, creating a kind of expanding bubble of gas. What happens when a star becomes 'spaghetti'? When a star ventures too close to a black hole, the difference in gravity between the side closest to the black hole and the side furthest away becomes extreme. This causes the star to be squeezed and stretched into long, thin strands—hence the term spaghettification. In AT 2022wtn, this shredded material formed a whirling disk of plasma. Some of the star's material spiraled into the black hole, while other parts were blasted away into space as jets and high-speed outflows. The team also detected a brief burst of radio waves, confirming these explosive emissions. Why is this discovery so important for science? This rare black hole-star interaction not only gave scientists a detailed view of how TDEs form, but also helped them understand the physical conditions around black holes during galaxy mergers. According to the research team, the study provides new evidence that supports the idea that galaxy collisions can trigger black holes to become more active. It also adds crucial data on how TDEs evolve, how accretion disks form, and how the resulting radiation is produced. Their findings were published on May 23 in the Monthly Notices of the Royal Astronomical Society. A cosmic warning and a clue to galaxy growth? While Earth is safe from such destruction (our Sun isn't near any massive black holes), these events serve as important reminders of the raw power of gravity and the extreme physics happening in deep space. More importantly, they give us clues about how black holes grow, how they interact with their environment, and how they may even shape the galaxies around them. For astronomers, AT 2022wtn is more than a violent end for one star—it's a rare and valuable opportunity to study the life cycle of galaxies and the monstrous forces that control them. FAQs: Q1: What is a tidal disruption event in a galaxy merger? A tidal disruption event is when a star gets torn apart by a supermassive black hole during a galactic collision. Q2: Why is AT 2022wtn important for black hole research? It's a rare case of a black hole eating a star during a galaxy merger, offering new insights into black hole behavior.
Time of India
27-05-2025
- Science
- Time of India
Astronomers stunned as sleeping Black Hole roars back to life after 20 years
The night sky was once thought of as a calm, unchanging dome, but over the years, it has become a dynamic canvas for discovery. Modern telescopes like the Zwicky Transient Facility (ZTF) are now looking deep into the night sky and the cosmos in real time, capturing sudden flashes, flares, and transformations as they happen. The advancement in technology every day is giving ways to observe the universe and witness cosmic events that happen over days, weeks, or even years, events that were previously considered too rare or distant to catch in action. One such surprise came up during late 2019, when a quiet galaxy, SDSS1335+0728, suddenly lit up in the Virgo constellation, located about 300 million light-years from Earth. What followed has kept astronomers captivated for over four years, and the show isn't over yet. What is happening in the cosmos? In December 2019, astronomers spotted that the quiet core of SDSS1335+0728, a spiral galaxy in the Virgo constellation, suddenly brightened by several orders of magnitude. Located about 300 million light-years away, this galaxy had shown no signs of activity for over two decades. Now, its center home to a supermassive black hole roughly a million times the mass of the Sun was blazing to life. Astronomers immediately suspected either a tidal disruption event, where a star gets torn apart by a black hole's gravity, or the first signs of an active galactic nucleus (AGN) waking up. But what made this case unusual was the duration. More than four years later, the flare hasn't faded, far exceeding the timescale of typical star-eating episodes or supernovae. 'This behavior is unprecedented,' said Paula Sánchez Sáez, lead author of the study published in Astronomy & Astrophysics and an astronomer at the European Southern Observatory (ESO) in Germany. Instruments including ESO's X-shooter spectrograph detected a consistent rise in ultraviolet, optical, and infrared light—and in February 2024, X-ray emissions began for the first time. The spectrum now reveals broad emission lines, meaning gas moving near light-speed close to the black hole. 'Suddenly, its core starts showing dramatic changes in brightness, unlike any typical event we've seen before,' Sánchez Sáez added. Co-author Lorena Hernández García of the Millennium Institute of Astrophysics (MAS) in Chile noted, 'If so, this would be the first time that we see the activation of a massive black hole in real time.' There is a new nuclear activity in space That makes SDSS1335+0728 a cosmic rarity. It doesn't shine as brightly as classic quasars, but its persistence rules out most common flare types. It sits in a gray area, possibly marking a new category of nuclear activity. 'This could also happen to our own Sgr A*, the massive black hole at the center of our galaxy,' said Claudio Ricci of Diego Portales University in Chile. 'But it's unclear how likely that is.' Researchers are now trying to determine whether this is a very slow tidal disruption, the birth of a new accretion disk, or something never seen before. Each scenario could reshape models of how supermassive black holes evolve today. 'We expect that instruments such as MUSE on the VLT and those on the upcoming Extremely Large Telescope will be key to understanding why the galaxy is brightening,' said Sánchez Sáez.
