James Webb Reveals Secrets of Giant Stars in the Early Universe

A model of the NASA Hubble Space Telescope (Image via Getty)

Discovery of Early Giant Stars

Astronomers utilizing the James Webb Space Telescope (JWST) have uncovered compelling evidence for a unique type of massive star that may have existed in the early universe. These stars are believed to have emerged shortly after the Big Bang and are no longer present today. According to scientific theories, these stars were significantly larger than any currently known stars and had extremely short lifespans.

The evidence supporting this hypothesis is not derived from direct images but rather from chemical residues found in distant galaxies. These residues serve as records of the birth and death of the first stars. The discovery was made by studying a galaxy named GS 3073, which is located approximately 12.7 billion light-years away and appears as it did about 1.1 billion years after the Big Bang.

Chemical Patterns and Stellar Fingerprint

Data from the JWST revealed a distinctive chemical pattern within GS 3073 that does not align with what is expected from known stars. Scientists believe this pattern is indicative of stars with masses ranging from 1,000 to 10,000 times that of the sun. These stars likely collapsed into singularities within a period of about 250,000 years after their demise.

This finding could be crucial in understanding the origin of supermassive black holes that appeared in the early universe. Such black holes, with masses equivalent to millions of suns, have puzzled scientists due to their rapid growth in young galaxies. The research was published in the journal The Astrophysical Journal Letters.

Unusual Chemistry and Cosmic Fingerprints

The key evidence for this research comes from the chemical composition of GS 3073. The JWST data showed an unusually high amount of nitrogen compared to oxygen. The nitrogen-to-oxygen ratio measured at 0.46 cannot be explained by normal stars or known stellar explosions.

Daniel Whalen of the University of Portsmouth stated, “With GS 3073, we have the first observational evidence that these monster stars existed.” Scientists explain that elements created inside stars are released into space when they lose mass or die. These elements then become part of the gas in a galaxy, preserving a record of earlier stars.

Devesh Nandal of the Center for Astrophysics, Harvard and Smithsonian, added, “Chemical abundances act like a cosmic fingerprint.” He noted that the nitrogen levels in GS 3073 match predictions for extremely massive, early-generation stars.

To test this theory, researchers developed computer models of stars with masses ranging from 1,000 to 10,000 times that of the sun. The models demonstrated that these stars could generate large amounts of nitrogen through internal fusion processes. Carbon produced in the core moves into the outer layers, where it reacts with hydrogen to form nitrogen. Over time, this nitrogen spreads through the star and escapes into space, enriching the surrounding gas.

Stars of different mass ranges do not produce the same chemical results, making these early giant stars the best explanation for the observations.

Early Black Holes and Short-Lived Stars

The study also provides a possible explanation for how supermassive black holes formed so early in cosmic history. Observations indicate that some galaxies, less than 1 billion years after the Big Bang, already contain black holes millions of times more massive than the sun.

Researchers suggest that these early massive stars ended their lives by collapsing directly into black holes. Unlike many stars today, they likely did not explode as supernovae. Whalen explained that the stars “burned brilliantly for a brief time before collapsing into massive black holes.” Because there was no significant explosion, much of the star’s mass could remain in the black hole.

GS 3073 contains an actively feeding supermassive black hole. Scientists believe it may have grown from smaller black holes formed by the collapse of these early stars, followed by mergers over time.

The research team plans to search for more galaxies with similar chemical signatures. Identifying additional examples would help confirm that these massive early stars were common and played a key role in shaping early galaxies and black holes.