Signs of Monster Stars 10,000 Times Our Sun's Mass Found at The Dawn of Time

The characteristics of the first stars in the universe are unknown. We have only seen traces of them while gazing into the far reaches of the early Universe.

But a new line of evidence found in images from the James Webb Space Telescope appears to support a recent theory that is gaining traction: absolute colossi with masses up to 10,000 Suns were fusion-powered balls of heat and fury that appeared not long after the appearance of the first stars, if not among them.

According to astronomer Corinne Charbonnel of the University of Geneva in Switzerland, "We believe we have found a first clue of the presence of these extraordinary stars today, thanks to the data collected by the James-Webb Space Telescope."

A kind of star group known as a globular cluster is the first component of this puzzle. There are around 157 objects classified as globular clusters in the Milky Way, making them rather common in our neighborhood of the universe. They are spherical, very dense clusters with between 100,000 and 1 million stars. The chemical makeup of all of these stars is remarkably identical, indicating that they all formed from the same cloud of gas at around the same time.

Astronomers see these ancient globular clusters as "fossils" of the early Universe and study them to get knowledge about the chemistry of eons past. They also frequently include very old stars on the verge of extinction.

However, there is a really odd quality to these older globular clusters. They show relative depletion of carbon and oxygen and enrichment of helium, nitrogen, and sodium, chemical abundance ratios that vary from star to star and are difficult to understand.

Hydrogen burning at extremely high temperatures is the hypothesis that best matches these abundances. In 2013, scientists hypothesized that the cores of big stars may be one place where very high temperatures might exist. really large stars. possibly supermassive, with cores that are far hotter and under much higher pressures than those of the stars we currently observe in our vicinity, with masses of roughly 10,000 solar masses.

Then, in 2018, Charbonnel and her colleague Mark Gieles from the University of Barcelona in Spain came to the conclusion that it was feasible for the stellar wind released by these stars to "pollute" the interstellar medium of globular clusters with these elements. Gieles was formerly at the University of Surrey. The star's mass was being restored as collisions with lesser stars continued. The chemical abundances sown by the giant stars in the early Universe would be inherited by any stars created from the tainted interstellar material.

Unfortunately, the light from those old, polluted stars has long since faded from vision; they have long since died.

Globular clusters are between 10 and 13 billion years old, whereas superstars have a maximum life of two million years, according to Gieles. "They consequently left the currently observed clusters extremely quickly. There are no direct traces left.

Although everything is fairly orderly, further observational data was needed. The JWST then focused on GN-z11, a galaxy that was discovered just 440 million years after the Big Bang and whose light has traveled for 13.3 billion years across expanding space before finally reaching us.

While JWST, the most potent space telescope ever built, was used to investigate the spectrum of light that GN-z11 conveyed to us across space and time, we had known about it for a few years.

The data turned out to be somewhat strange. Nitrogen is far more abundant than oxygen in the interstellar medium of GN-z11, with an abundance ratio that is more than four times that of the Sun. Strange, if compatible with how globular clusters have been observed to develop by astronomers.

After thorough analysis and modeling, Charbonnel and her coworkers discovered that the abundance ratios in globular clusters as well as GN-z11 can be consistently explained by giant stars between 1,000 and 10,000 solar masses that formed through runaway collisions of smaller objects.

As demonstrated by the simulations created by Laura Ramirez-Galeano, a Master's student on our team, the substantial nitrogen presence can only be explained by the burning of hydrogen at extremely high temperatures, which only the core of supermassive stars can achieve.

Although the data is far from definitive, it does point to where we might go for further details. In order to find these early chonker stars, the researchers aim to collect additional information about early galaxies via JWST. This in turn could provide light on other unanswered questions, such as how supermassive black holes developed in the early Universe and the characteristics of the first stars.

The researchers note that if the supermassive star scenario can be supported by further study, it will be a significant step toward better understanding globular clusters and supermassive star development in general.

In any case, the peculiar characteristics of GN-z11 that JWST has just discovered demand further research in order to comprehend the physical processes occurring in such extreme objects in the early Universe and their potential connections to the formation of globulars, supermassive stars, and potentially even supermassive black holes, among other things.

The research has been published in Astronomy & Astrophysics.