Researchers wielding the capabilities of the NASA/ESA/CSA James Webb Space Telescope have identified spectroscopic indicators of nascent stars, each possessing a mass ranging from 1,000 to 10,000 times that of our Sun, within the ancient galaxy designated GS 3073. This galaxy is situated at a redshift of 5.55, corresponding to approximately one billion years post-Big Bang.
A primordial supermassive star in the early Universe. Image credit: Gemini AI.
In the year 2022, theoretical models proposed by astronomers posited that colossal stars would naturally materialize within scarce, turbulent conduits of frigid gas prevalent in the nascent universe, thereby offering an explanation for the existence of quasars at epochs preceding one billion years after the universe’s inception.
“Our most recent finding contributes significantly to resolving a cosmological enigma that has persisted for two decades,” stated Dr. Daniel Whalen, an astrophysicist affiliated with the University of Portsmouth.
“In the case of GS 3073, we have secured the inaugural empirical substantiation for the actual existence of these prodigious stellar entities.”
“These celestial behemoths would have blazed with immense luminosity for a confined duration before undergoing gravitational collapse to become massive black holes, leaving behind the chemical imprints that we are able to discern billions of years hence.”
“Much like the dinosaurs on Earth, they were characterized by their immense scale and primordial nature. Furthermore, their lifespans were ephemeral, lasting only a quarter of a million years—a fleeting moment in cosmic terms.”
The pivotal factor in this groundbreaking discovery was the precise quantification of the nitrogen-to-oxygen ratio observed within the GS 3073 galaxy.
This particular galaxy exhibits a nitrogen-to-oxygen ratio registering at 0.46, a value substantially exceeding that which can be accounted for by any currently understood stellar type or stellar cataclysm.
“The relative abundances of chemical elements serve as unique cosmological signatures, and the spectral pattern identified in GS 3073 is fundamentally distinct from anything generated by conventional stars,” remarked Dr. Devesh Nandal, a researcher at the University of Virginia and the Harvard-Smithsonian Center for Astrophysics.
“Its exceptionally high nitrogen content aligns exclusively with a singular known source: presolar stars possessing masses thousands of times greater than that of our Sun.”
“This observation indicates that the initial stellar population encompassed truly colossal objects that played a crucial role in shaping the early galaxies and may have been the progenitors of the supermassive black holes observed today.”
The research team meticulously simulated the evolutionary pathways of stars with masses ranging from 1,000 to 10,000 solar masses and the elemental products they synthesized.
Their findings pinpointed a specific nucleosynthetic pathway responsible for generating substantial quantities of nitrogen: (i) these gargantuan stars undergo helium fusion in their cores, yielding carbon; (ii) this carbon then diffuses into an adjacent surrounding shell where hydrogen fusion is occurring; (iii) the carbon subsequently fuses with hydrogen, resulting in the production of nitrogen via the carbon/nitrogen/oxygen (CNO) nucleosynthesis cycle; (iv) convective motions within the star facilitate the redistribution of this newly formed nitrogen throughout its structure; and (v) ultimately, this nitrogen-enriched material is expelled into the interstellar medium, thereby augmenting the chemical composition of the surrounding gas.
This intricate process persists for millions of years during the star’s helium-burning phase, leading to the accumulation of the nitrogen surplus observed in GS 3073.
Furthermore, the models developed by the research group prognosticate the ultimate fate of these titanic stars—they do not undergo supernovae; rather, they experience direct gravitational collapse to form nascent black holes with masses in the thousands of solar mass range.
Intriguingly, GS 3073 harbors an actively consuming black hole at its core, which may very well be the direct remnant of one of these primordial supermassive stars.
Should this hypothesis be substantiated, it would concurrently resolve two profound cosmological mysteries: the origin of the observed nitrogen enrichment and the formation mechanism of the central black hole.
The investigation also revealed that this distinctive nitrogen signature is exclusively detected within a narrow mass spectrum.
“Stars with masses below 1,000 solar masses or exceeding 10,000 solar masses do not generate the requisite chemical profile for this signature, indicating the existence of a specific ‘optimal range’ for this particular type of nucleosynthetic enrichment,” the scientific personnel concluded.
The comprehensive study has been formally documented and disseminated in the Astrophysical Journal Letters.
_____
Devesh Nandal et al. 2025. 1000-10,000 MSun Primordial Stars Created the Nitrogen Excess in GS 3073 at z = 5.55. ApJL 994, L11; doi: 10.3847/2041-8213/ae1a63
