Pleiades: Expert gives tips on spotting star clusters
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Astronomers have said the newly-found star is acting like it is Betelgeuse but “on steroids”. Between December and January 2020, a distant star known as Betelgeuse began dimming rapidly, leaving astronomers questioning whether the star, which is 725 light-years from Earth, was ready to explode. In December 2019, Betelgeuse went from one of the top 10 brightest stars visible to the naked eye to the 21st in January – of roughly 5,000 which can be seen.
The dimming suggested it was expected to supernova. Stars supernova when they are at the end of their lives and have run out of fuel after millions of years.
However, the star, which is located in the constellation Orion, regained some of its brightness, prompting an investigation from NASA’s Hubble Telescope to determine what was causing the sporadic dimming.
The space agency revealed the star ejected hot material from its core, which formed around Betelgeuse.
NASA has now spotted another star acting in a similar fashion, and wanted to see if the cause was the same – and the agency was stunned by the findings.
The star is a red hypergiant known as VY Canis Majoris, found in the adjoining constellation of Canis Major.
Study lead author Roberta Humphreys of the University of Minnesota, Minneapolis, said: “VY Canis Majoris is behaving a lot like Betelgeuse on steroids.
“In VY Canis Majoris we see something similar, but on a much larger scale.”
VY Cannis Majoris is about 300,000 times brighter than the Sun, but it was once much more visible.
NASA said it is no longer visible to the naked eye, even though it was just a century ago.
Experts have put this down to huge ejections of plasma that surround the star, meaning it is essentially shedding.
Dr Humphreys said: “Massive ejections of material which correspond to its very deep fading, which is probably due to dust that temporarily blocks light from the star.
“This star is absolutely amazing. It’s one of the largest stars that we know of — a very evolved, red supergiant.
“It has had multiple, giant eruptions. It’s amazing the star can do it.
“The origin of these high mass-loss episodes in both VY Canis Majoris and Betelgeuse is probably caused by large-scale surface activity, large convective cells like on the Sun.
“But on VY Canis Majoris, the cells may be as large as the whole Sun or larger.”
According to Dr Humphreys, this is the first time scientists have observed a major star in this stage of its evolution.
She said: “So what’s special about it? VY Canis Majoris may be in a unique evolutionary state that separates it from the other stars.
“It’s probably this active over a very short period, maybe only a few thousand years. We’re not going to see many of those around.”
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