About 11.5 billion years ago, a distant star about 530 times larger than our sun died in a cataclysmic explosion that blew its outer layers of gas into the surrounding universe, a supernova. recorded in detail by astronomers.
Researchers on Wednesday said NASA’s Hubble Space Telescope captured three separate images over an eight-day period starting just hours after the explosion – an even more remarkable achievement. than when it happened how long ago and at a distance.
According to astronomer Wenlei Chen, a postdoctoral researcher at the University of Minnesota and lead author of the study published in the journal Nature, these images were discovered during a review of archival data. Hubble observations since 2010.
They offer the first look at a supernova that cooled rapidly after the initial explosion in a single set of images, and the first insight into a supernova very early in the history of the universe, when it was not full 1/5 of the present age.
“The supernova is expanding and cooling, so its color changes from hot blue to cold red,” said University of Minnesota astronomy professor and study co-author Patrick Kelly.
The perishing star, a type known as a red supergiant, resides in a dwarf galaxy and explodes at the end of its relatively short life.
“Red supergiants are bright, massive, and massive stars, but they’re much cooler than most other high-mass stars – that’s why they are colored,” says Chen. red. “After a red supergiant has exhausted the fusion energy in its core, core collapse will occur, and the supernova explosion will then blow up the star’s outer layers – the hydrogen shell of the star. it.”
The first image, from about six hours after the first explosion, shows the explosion starting out relatively small and intensely hot – about 180,000 degrees Fahrenheit (100,000 degrees Kelvin / 99,725 degrees Celsius).
The second image is from about two days later and the third is from about six days later. In these two images, the gaseous matter ejected from the star is seen expanding outward. In the second image, the explosion is only 1/5 as hot as the first image. In the third photo, it’s only a tenth as hot as the first.
The remnants of the star that exploded could very well become an extremely dense object called a neutron star, Chen said.
A phenomenon known as strong gravitational lensing explains how Hubble was able to obtain three images at different points in time after the explosion. The enormous gravitational force exerted by a cluster of galaxies in front of the exploding star from Earth’s point of view acts as a lens – bending and magnifying the light emitted by the supernova.
“The gravitational force in the galaxy cluster not only bends light from behind it, but it also delays the travel time of light because the stronger the gravity, the slower the clock moves,” said Chen. “In other words, light emission from a single source behind the lens can pass through many paths towards us, and then we see multiple images of the source.”
Kelly calls the ability to see a supernova cool rapidly in a single set of images by gravitational lensing “absolutely amazing.”
“It’s like seeing a color film of a growing supernova, and it’s a much more detailed picture of any known supernova that existed when the universe was just one,” said Kelly. small compared to the present age”.
Kelly added: “The only other examples we’ve seen of a very early supernova are very nearby explosions. “When astronomers see more distant objects, they are going back in time.”
(Except for the title, this story has not been edited by NDTV staff and is published from an aggregated feed.)
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