A dead star surprises scientists by returning to life.. What is the story?
Arabia Weather - Apparently, a distant star has returned to life after it exploded, radiating repeated active flares over an incomparable period according to astronomers.
Although all the luminosity remains for a short period 100 days after the first explosion, it remains as bright and powerful as it was during the original explosion - a unique type of stellar event known as a "Luminous Fast Blue Optical Transient" or LFBOT.
Located about a billion light-years from Earth, the rare phenomenon has been officially named AT2022tsd. LFBOT appears brighter than the typical explosions that signal the death of massive stars, but fades more quickly after the explosion, over days rather than weeks.
This extreme phenomenon was first discovered in 2018, and over the last half decade since then, its origin has remained a mystery. However, the previous flare activity of this Tasmanian star suggests that this behavior, which has been observed by 15 different telescopes around the world, may have occurred. Offering some answers, this behavior seems to link LFBOTS to either a black hole or a neutron star — which are the posthumous remains of massive stars.
Detecting superluminous gas and irregular flares in the universe of massive stars
In order to explore this unexpected type of "return to life" phenomenon by the Tasmanian star, the team collected observations from 12 other telescopes, including one that captured the event with a high-speed camera. After ruling out other potential light sources, the researchers were left with 14 light pulses. The irregular flare occurred over the course of 120 days and researchers believe this may be just a small fraction of the total flares generated by the entire event.
Professor Ho, lead author of the research, noted:
“Amazingly, instead of steadily fading as expected, the source briefly brightened again – again and again.”
“LFBOTs are already kind of weird and weird events, so this was even weirder,” she added.
Now, she and her team intend to investigate the processes that lead to these light outbursts, and the current main suspects are jets of matter funneled by the black hole's magnetic field, which explode at light-like speeds. However, the possibility remains that LFBOTs are caused by black holes colliding and merging. .
Professor Ho said:
“We may be seeing a completely different channel for cosmic catastrophe.” This research is expected to help reveal more about how stars die, as well as the types of stellar debris they leave behind. Essentially, LFBOTs may provide the opportunity to observe stars as they transition from "life" to "death."
The rapidly fading lights of massive stars and their new astronomical mysteries
LFBOTs also appear to fade more quickly after death, over a short period of days rather than weeks. These extreme phenomena were first discovered in 2018, and for the last half of the past decade, their origins have remained a mystery. However, the glow activity appears to be... This behavior, observed by 15 telescopes around the world, suggests that the engine running LFBOTS is either a black hole or a neutron star - which are the remains left behind by massive stars after they die. .
In this context, Anna Y. Kew Ho, lead author of the research and assistant professor of astronomy at Cornell University, said:
"We don't think anything else could produce these kind of flares."
She added:
“This curtain raises the curtain on years of debate about what drives these types of explosions, and reveals an unusual and direct way to study the activity of stellar bodies.”
The Tasmanian star was first identified by its development program in September 2022, as the system was sifting through data containing about half a million variable objects. It was discovered through the Zwicky Transient Facility and later, during routine LFBOT monitoring during its disappearance in December 2022. She and her colleagues discovered another bright spike of light, which suddenly appeared, then immediately disappeared. This unusual new appearance is among the most unique astronomical phenomena. She said:
“We have never seen anything like this before, with such tremendous speed and brightness, months after the first explosion of any supernova or FBOTs.”
Read also:
Artificial intelligence helps astronomers estimate the ages of stars
Under the stars.. Walking at night helps you sleep
Sources:
Browse on the official website