spaceSpace and PhysicsspaceAstronomy

"Celestial Monster" Stars Up To 10,000 Times Our Sun's Mass Left Clues For JWST

The space observatory found an intriguing detection pointing at the very first stars.


Dr. Alfredo Carpineti


Dr. Alfredo Carpineti

Senior Staff Writer & Space Correspondent

Alfredo (he/him) has a PhD in Astrophysics on galaxy evolution and a Master's in Quantum Fields and Fundamental Forces.

Senior Staff Writer & Space Correspondent

This image from the NASA/ESA Hubble Space Telescope shows NGC 6388, a dynamically middle-aged globular cluster in the Milky Way. While the cluster formed in the distant past (like all globular clusters, it is over ten billion years old), a study of the distribution of bright blue stars within the cluster shows that it has aged at a moderate speed, and its heaviest stars are in the process of migrating to the centre.

NGC 6388 a globular cluster in the Milky Way.

Image Credit: NASA, ESA, F. Ferraro (University of Bologna)

Humanity has never observed the very first stars that shone in the universe. They lived fast and died young, but they were the ones that created the heavier elements that eventually ended up making us. Astronomers now suggest that some recent observations of very distant galaxies can only be explained by the presence of enormous stars.

The team called them "celestial monsters", and they are not kidding. These are stars between 5,000 and 10,000 times the mass of our Sun that lived at most for two million years. At their cores, they were five times hotter than the center of the Sun.


These supermassive stars formed in many different environments, but the one that intrigued researchers was globular clusters. These are the most massive and oldest clusters of stars in the universe, and they are very dense. Astronomers believe that these supermassive stars formed in globular clusters as well – not that they can be seen directly yet, unfortunately.

“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, ICREA professor at the University of Barcelona, said in a statement

But they do leave something behind: heavier elements. And it is this signature that JWST has spotted in galaxy GN-z11, an object that for a while held the title of the most distant known galaxy. Thanks to JWST's observations, astronomers have learned a lot more about this object whose light comes from just 400 million years after the Big Bang. 

“It has been established that it contains very high proportions of nitrogen and a very high density of stars,” added co-author Daniel Schaerer from the University of Geneva. 


And the extra nitrogen is seen as a telltale sign of the fleeting but crucial presence of the supermassive stars in these globular clusters. You wouldn’t get as much of that element unless you had stars massive enough. 

“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, as shown by the models of Laura Ramirez-Galeano, a Master’s student in our team,” explained lead author Professor Corinne Charbonnel, also from the University of Geneva.

The model can explain the anomaly in the abundance of nitrogen but it is not definite proof of the supermassive stars having been there. The team plans to use more JWST observations of distant galaxies to further strengthen their work.

The study is published in the journal Astronomy and Astrophysics.


spaceSpace and PhysicsspaceAstronomy
  • tag
  • stars,

  • JWST,

  • Astronomy,

  • globular cluster,

  • star clusters,

  • Population III stars,

  • distant universe