James Webb detects 'celestial monster' stars 10,000 times the mass of the Sun

James Webb provides first evidence of early supermassive stars

The team behind the discovery detected chemical traces of the enormous stars inside globular clusters, which are tightly bound clusters of stars sometimes made up of millions of stars.

Globular clusters are incredibly old, making them targets for astronomers who wish to peer into the universe's ancient past.

The researchers, who published their findings in a paper in the journal Astronomy and Astrophysics, believe the discovery could help us better understand how heavy elements were first formed in our universe.

They trained James Webb's infrared camera on the galaxy GN-z11, one of the most distant and oldest galaxies ever discovered, some 13.3 billion light-years away from Earth.

They then took spectroscopy readings — measuring the light frequencies emitted by different chemicals — to determine that high nitrogen levels surrounded the stars in the ancient cluster.

"The strong presence of nitrogen can only be explained by the combustion of hydrogen at extremely high temperatures, which only the core of supermassive stars can reach," Charbonnel explained.

NASA's Webb telescope sheds new light on early cosmos

Though globular clusters formed roughly at the same time and from the same dust and gas clouds from 13.4 billion years ago, they surprisingly contain stars with very different proportions of elements.

Scientists have hypothesized that this may be down to supermassive stars that burned their fuel at much higher temperatures, meaning they were able to produce heavier elements that eventually made their way to the smaller stars that are more common today.

Though these supermassive stars will have burned with a brightness up to 10,000 times higher than our Sun, detecting them is surprisingly challenging. That's because they all exploded in massively violent events called hypernovas a very long time ago.

"Globular clusters are between 10 and 13 billion years old, whereas the maximum lifespan of superstars is two million years. They therefore disappeared very early from the clusters that are currently observable. Only indirect traces remain," co-author Mark Gieles, a professor of astrophysics at the University of Barcelona, said in the statement. 

Thankfully, James Webb's incredible capacity to peer into the distant past has provided direct evidence of their existence. Next, the team of researchers aims to investigate more ancient globular star clusters to see if they can detect more traces of early supermassive stars.