To Evolution

The Rare Cosmic Alignment Reveals The Most Distant Star Ever Seen

    Abdulaziz Sobh
    By Abdulaziz Sobh

    Categories: Science


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    The Hubble Space Telescope has broken another observation record: the famous observatory has found the most distant "distant" star ever seen, a staggering 9 billion light-years from Earth, which means that light scientists began to travel at least 9 billion years ago. In comparison, the age of the universe is approximately 13,800 million years. Normally, stars so far away are too difficult to distinguish individually; A galaxy or a supernova (explosion of stars) is much easier to see. But this particular star classified as an ordinary star, that is, a star in the main sequence of evolution that is fusing hydrogen into helium, came to light thanks to a strange alignment, researchers reported in a new study. When a main sequence star stops burning the hydrogen in its core, it leaves the main sequence. This leads to a variety of different results for the stars. Commonly, the larger stars of the main sequence explode into supernovas, while the smaller stars collapse into white dwarfs.The astronomers found the star, nicknamed Icarus, through gravitational lenses. This phenomenon refers to how a massive galaxy cluster or another object can bend the light of the objects behind it, making the faint objects much brighter from the perspective of the Earth. [In photos: Cosmic lenses reveal the expansion of the universe]Typically, this lens process can magnify objects up to 50 times, but astronomers were lucky here: the newly discovered star was enlarged more than 2,000 times because a star briefly passed through the line of sight between Hubble and Icarus, the scientists said. researchers in a statement from the University of California, Berkeley. This rare glimpse of a distant star could provide a window into how stars evolve in general, especially those that are extremely bright, the team said."You can see individual galaxies, but this star is at least 100 times farther than the next individual star we can study, except for the supernova explosions," study author Patrick Kelly said in the statement. Kelly was a postdoctoral researcher at the University of California, Berkeley, when he worked in research, but is currently on the faculty of the University of Minnesota.Icarus, more formally known as MACS J1149 Lensed Star 1 (LS1), appeared when Kelly was following a supernova, called SN Refsdal, which he discovered in 2014. The supernova was discovered using a gravitational lens in the constellation of Leo; The lens was formed by a cluster of galaxies known as MACS J1149 + 2223."For the first time, we are seeing an individual normal star, not a supernova, nor a gamma-ray explosion, but a single stable star, at a distance of nine billion light years," co-author of the study, Alex Filippenko. , an astronomer at UC Berkeley, said in the same statement. These lenses are amazing cosmic telescopes. "Kelly's team examined the colors from the light of Icarus and discovered that it was a blue supergiant. This type of star is more massive and bigger than our sun, shining hundreds of thousands of times brighter. Even so, Icarus was so far away that astronomers would never have seen it without powerful lenses. Kelly suspected that the star was much more enlarged than the supernova, a hypothesis later confirmed by modeling."In modeling the lens, [the astronomers] came to the conclusion that Icarus' apparent great improvement was probably due to a unique effect of the gravitational lens," UC Berkeley representatives said in the statement. "While an extended lens, such as a cluster of galaxies, can only enlarge a background object up to 50 times, smaller objects can increase much more."A single star in a close-up lens, if aligned with a background star, can magnify the background star thousands of times," they added. "In this case, a star the size of our sun passed briefly directly through the line of sight between the distant star Icarus and Hubble, increasing its brightness more than 2,000 times."Fortunately for astronomers, Icarus is well located for more of these alignments. As the stars of the MACS J1149 + 2223 cluster move, the brightness of Icarus could increase up to 10,000 times during other lens events. Astronomers may catch more of these rare events in general if they look in the right place, the team added."There are alignments like this everywhere as the stars or background stars move around the galaxies, offering the possibility of studying very distant stars that date from the primitive universe, just as we have been using gravitational lenses to study distant galaxies", Filippenko He said in the statement. "For this type of research, nature has provided us with a larger telescope than we can possibly build."Icarus appeared in Hubble images taken between April 2016 and April 2017. A second star appeared in some observations that could be a mirror image of Icarus or a star more gravitationally.Astronomers also probed dark matter, a poorly understood substance that makes up most of the universe, with observations of Icarus. In contrast to what some earlier theories have claimed, the new observations suggest that dark matter is not composed of primordial black holes within galaxy clusters.