The explosive demise of a distant star leaves behind the corpse of an active star, which is thought to be the source of multiple high-energy flares detected over several months. The phenomenon, something astronomers have never seen before, was recently reported by a team led by Cornell University in a study published in the journal Science. Nature.
The bright, short flashes (lasting just a few minutes and as powerful as the first explosion 100 days later) appeared in the aftermath of a rare type of stellar cataclysm (known as a luminescence event) that researchers were hoping to discover. Ta. Fast Blue Light Transient, or LFBOT.
Since the discovery in 2018, astronomers have speculated about what could cause such an extreme explosion. This explosion is much brighter than the violent outbursts that massive stars typically experience, but it fades away in days rather than weeks. The research team is convinced that the engine must be the remains of a star, due to previously unknown flare activity studied with 15 telescopes around the world. Black Hole or neutron star.
Unique astronomical event: AT2022tsd
“We don’t think there’s anything else that can cause this kind of flare,” said Anna YQ Ho, assistant professor of astronomy in the College of Arts and Sciences. “This settles a long-standing debate about the dynamics of these types of explosions and reveals an unusually direct way to study the activity of stellar corpses.”
Ho is one of more than 70 people who helped characterize the LFBOT, officially named AT2022tsd and nicknamed the “Tasmanian Devil,” and its subsequent light pulse, seen about 1 billion light-years from Earth. He is the lead author of a recent study published with co-authors.
Ho wrote the software to alert him to this event in September 2022 while scrutinizing the 500,000 changes, or transients, detected each day in an all-sky survey conducted by the California-based Zwicky Transient Facility. .
And in December 2022, while regularly monitoring the fading explosion, Ho and his collaborators Daniel Perley from Liverpool John Moores University in the UK and Ping from the Weizmann Institute of Science in Israel Mr. Chen met to review new observations made and analyzed by Ping. It consists of 5 images, each lasting several minutes. The first one showed nothing, as expected, but the second one picked up light, followed by a very bright spike in the center frame, which quickly disappeared.
“Nobody really knew what to say,” Ho recalled. “We’ve never seen anything like a supernova or FBOT so fast and as bright as the initial explosion several months later. We’ve never seen anything like that in astronomy. There was no.”
To further investigate the sudden brightness, the researchers collaborated with partners who contributed observations from more than a dozen other telescopes, including one equipped with a high-speed camera. The team combed through previous data and worked to rule out other possible light sources. Their analysis ultimately identified at least 14 irregular light pulses over 120 days, Ho said, but likely only a fraction of the total number.
“Surprisingly, instead of steadily dimming as expected, the light source briefly brightened again, over and over again,” she said. “LFBOT is already kind of a weird, exotic event, so this was even weirder.”
Stellar evolution and its impact on cataclysms
Exactly what process was at work, possibly causing the black hole to eject jets of stellar material outward at near the speed of light, continues to be studied. Ho hopes this research will advance a long-held goal of predicting how a star dies and what kind of corpse it produces based on its properties during its lifetime.
In the case of LFBOT, Ho said, high-speed rotation or a strong magnetic field are likely key elements of the firing mechanism. It’s also possible that they were caused by a merger between a star and a black hole, rather than a traditional supernova.
“We may be seeing a completely different path of cosmic cataclysm,” she says.
This unusual explosion is expected to provide new insights into the life cycle of stars, which are typically not part of a single system and are only seen in snapshots of different stages (stars, explosions, debris). Yes, Ho said. LFBOT could provide an opportunity to observe stars as they transition into the afterlife.
“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.”
Reference: “Minute-by-minute optical flares due to supernova luminosity” Anna YQ Ho, Daniel A. Perley, Ping Chen, Steve Schulze, Vik Dhillon, Harsh Kumar, Aswin Suresh, Vishwajeet Swain, Michael Bremer, Stephen J. Smartt, Joseph P Anderson, GC Anupama, Supachai Awifan, Sudhanshu Barway, Eric C. Bellm, Sagi Ben-Ami, Varun Barao, Thomas de Boer, Thomas G. Brink, Rick Burrus, Poonam Chandra, Tingwan Chen. , Wenping Chen, Jeff Cook, Michael W. Coughlin, Kaustav K. Das, Andrew J. Drake, Alexei V. Filipenko, James Freeburn, Christopher Fremling, Michael D. Fulton, Avishay -Gal-Yam, Luis Galvani, Hua Gao, Matthew J. Graham, Maus Gromacki, Claudia P. Gutierrez, K-Ryan Hines, Cosimo Inserra, Nayana AJ, Viraj Karamberkar, Mansi M. -Kasliwal, Shri Kulkarni, Thomas E. Muller Bravo, Eugene A. Magnier, Ashish A. Mahabal, Thomas Moore, Chow Chun Nyo, Matt Nichol, Elan O. Ofek, Connor MB. Omand, Francesca Honori, Yen Chen Pang, Priscilla J. Pesci, Glenn Petitpas, David Polihook, Saran Poshachinda, Mika Prussiainen, Reid Riddle, Antonio C. Rodriguez, Ben Rasholm , Enrico Segre, Yashvi Sharma, Ken W. Smith, Jesper Solerman, Shubham Srivastav, Nora Lynn Strojohan, Mark Sarr, Dmitri Svinkin, Yanan Wang, Philip Wiseman, Avery Wald, Shen Yang, Yi Yang, Yuhan Yao, Mr. David R. Young and Mr. Weikang Zheng, November 15, 2023. Nature.
DOI: 10.1038/s41586-023-06673-6