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New images reveal the secret of how supermassive stars are born

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We've long known how stars like our Sun are born, but we weren't sure about their much bigger counterparts. This image of a dust-shrouded, supermassive baby star offers some answers.

Located roughly 10,000 light-years away in the constellation of Centaurus, the star IRAS 13481-6124 is twenty times the Sun's mass and about five times bigger in diameter. Using NASA's Spitzer Space Telescope, astronomers discovered the star is still in the last stage before its "birth," encircled by a telltale disc of dust and gas.

That sort of disc has never been seen around such a massive star before. Astronomers already knew smaller stars had these prenatal discs before they reached final mass, but they were unsure whether such discs could survive the intensely bright light of stars more than ten times the mass of the Sun. However, without the extra mass that these dust discs provide, it wasn't clear how such stars ever attained their final mass. As an alternative, astronomers had proposed massive stars were actually the result of smaller stars falling into each other and merging.


Stefan Kraus, who led the team of astronomers, explains the significance of the find:

"Our observations show a disc surrounding an embryonic young, massive star, which is now fully formed. One can say that the baby is about to hatch!
"This is the first time we could image the inner regions of the disc around a massive young star. Our observations show that formation works the same for all stars, regardless of mass."


The star system is about 60,000 years old. Since IRAS 13481-6124 has reached its final mass, the disc will soon start to evaporate. That process will happen incredibly quickly because the star is an incredible 30,000 times brighter than our own Sun. The disc extends out about 130 times the distance between the Sun and Earth and weighs about as much as the star itself.

[Original Paper]