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The universe is full of extreme phenomena, but the Tasmanian devil may be one of the strangest and rarest cosmic phenomena ever observed.
Months after astronomers witnessed the explosion of a distant star, they discovered something they had never seen before. The idea is that energetic signs of life are being emitted from a dead star about 1 billion light-years from Earth. The short, bright flare was just as powerful as the initial event that caused the star’s death.
Astronomers named the object the Tasmanian Devil and have observed it repeatedly exploding since it was first discovered in September 2022.
But the initial stellar explosion that caused this star’s death was not a typical supernova, one that gets brighter and brighter, explodes, sheds most of its mass, and then dies. Instead, it was an unusual type of explosion called a luminescent fast blue light transient (LFBOT).
LFBOTs shine brightly with blue light and dim within a few days after reaching their peak brightness, whereas supernovae can take weeks or months to dim.of The first LFBOT was discovered in 2018and ever since, astronomers have been trying to determine the cause of the rare catastrophe.
But the Tasmanian devil’s unexpected behavior reveals more questions than answers.
LFBOT is an unusual event, but the Tasmanian devil is even more unusual, leaving astronomers wondering about the process behind the repeated explosions.
“Surprisingly, rather than steadily dimming as expected, the light source briefly brightened again, over and over again,” said Cornell University College of Arts and Sciences, lead author of the study. said Anna Y. Q. Ho, assistant professor of astronomy at , in a statement. “LFBOT is already kind of a weird, exotic event, so this was even weirder.”
The findings on the latest Tasmanian devil LFBOT discovery, officially labeled AT2022tsd and observed with 15 telescopes around the world, were published Wednesday in the journal Nature.
“(LFBOT) emits more energy than an entire galaxy of hundreds of billions of stars like our Sun. The mechanism behind this enormous amount of energy is currently unknown,” said study co-author. Geoff Cook, professor at Australia’s Swinburne University of Technology and the ARC Gravitational Wave Discovery Center of Excellence, said in a statement. “But in this case, after the initial explosion and dimming, the extreme explosions continued to occur very quickly, over a period of minutes rather than weeks or months as in the case of supernovae.”
The software written by Ho first flagged this event. The software sifts through his 500,000 transients detected daily by his Zwicky Transient Facility in California, which surveys the night sky. Ho and his collaborators from various agencies continued to monitor the explosion until it subsided, reconsidering their observations several months later. The image showed an intense bright spike of light that quickly disappeared.
“Nobody really knew what to say,” Ho said. “We’ve never seen anything like that before in a supernova or FBOT (fast blue light transient), something this fast and as bright as the initial explosion months later. I’ve never had that happen.
I had never seen anything like that in astronomy. ”
To better understand the rapid light changes occurring in the Tasmanian devil, Ho and colleagues contacted other researchers to compare observations from multiple telescopes.
Jason Kosky/Cornell University
Anna Ho has developed software that detects signs of life emanating from stellar corpses.
Fifteen observatories, including the high-speed camera ULTRASPEC on the 2.4-meter-long National Telescope of Thailand, tracked 14 irregular light pulses over 120 days, likely a fraction of the total number of flares emitted by LFBOT. Mr. Ho believes that it is no more than a department. He said.
Some of the flares lasted only tens of seconds, which suggests to astronomers that the root cause is stellar debris formed by the initial explosion, either a dense neutron star or a black hole. It suggests that.
“This settles a long-standing debate about the power source for these types of explosions and reveals an unusually direct way to study the activity of stellar corpses,” Ho said.
Both objects can take on large amounts of material, which facilitates their subsequent explosion.
“This pushes the boundaries of physics not only because of its extreme energy production, but also because of its short explosion time,” Cook said. “Light travels at a finite speed. Therefore, the size of the energy source is limited by how quickly it can burst and disappear. This means that all this energy can be generated from a relatively small energy source. It means that it has been done.”
If it’s a black hole, the object could be spewing out jets of material and shooting them across space at near the speed of light.
Another possibility is that the first explosion could have been caused by an unconventional event, such as the merger of a star and a black hole, which could indicate a “completely different path for a cosmic cataclysm.” Mr. Ho said that there is.
Studying LFBOT could reveal much more about a star’s life cycle than just its life cycle, which ends in explosion and debris.
“Because the bodies aren’t just sitting there, they’re active and doing things that we can detect,” Ho said. “These flares could be coming from one of these newly formed cadavers, and this gives us a way to study the properties of the just-formed cadaver.”
Astronomers will continue to study the sky to see how common LFBOT is and to uncover more of its secrets.
“This discovery tells us more about how stars end their lives in different ways, and about the foreign countries that inhabit our universe,” said study co-author Vic Dillon, professor in the School of Physics and Astronomy at the University of Sheffield, UK. he said. statement.