Astronomers have found the largest stars to date, including on that weighed more than 300 times the mass of the Sun at birth. This is twice as much as the current limit of 150 solar masses. And that makes for a pretty darn bright star.Using ESO’s Very Large Telescope (VLT)–yes, really– Paul Crowther, Professor of Astrophysics at the University 
of Sheffield, led a team of researchers in discovering these starts. Along with the VLT, the team used data from the archives of the NASA/ESA Hubble Space Telescope, to study two young clusters of stars.
These stars, NGC 3603 and RMC 136a, were explored in detail. NGC 3603, located 22000 light-years away from the Sun, is a cosmic factory where stars form extended clouds of gas and dust. RMC 136a is located inside the Tarantula Nebula, in a neighbouring galaxy, the Large Magellanic Cloud, 165 000 light-years away.
The team found that the surface temperatures of many of these stars was over 40 000 degrees, which is seven times hotter than the Sun. They were also tens of times larger and several million times brighter.The star R136a1, found in the R136 cluster, is largest star ever found.
“Unlike humans, these stars are born heavy and lose weight as they age,” explains Paul Crowther. “Being a little over a million years old, the most extreme star R136a1 is already ‘middle-aged’ and has undergone an intense weight loss programme, shedding a fifth of its initial mass over that time, or more than fifty solar masses.”
He continues: “[The R136’s] high mass would reduce the length of the Earth’s year to three weeks, and it would bathe the Earth in incredibly intense ultraviolet radiation, rendering life on our planet impossible,” says Raphael Hirschi from Keele University, who belongs to the team.
These rare stars keep the researchers puzzled; theorists, however, want to continue to explore the challenges to determine what makes them what they are, and how they form.
Not only is R136a1 the most massive star that has been discovered, but also the brightest, close to 10 million times greater than the Sun. “Owing to the rarity of these monsters, I think it is unlikely that this new record will be broken any time soon,” Crowther says.
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Image courtesy from apod.nasa.gov