James Webb telescope may have found the first stars in the universe, new study claims
Astronomers using the James Webb Telescope may have discovered some of the first stars in the universe and could offer clues to how galaxies formed. Using the James Webb Space Telescope (JWST) and a phenomenon first predicted by Albert Einstein, scientists have spotted the first stars, known as Population III stars, in a distant cluster called LAP1-B, located 13 billion light-years from Earth. They described their results on October 27 in Letters from the astrophysical journal.
Population III stars, sometimes called dark starsare theoretically among the first stars formed after the Big Bang about 13.8 billion years ago. According to this theory, hydrogen and helium combined with dark mattercreating gargantuan stars a million times the mass of the sun and a billion times brighter than our star.
For example, the spectra of stars, which show their composition based on the light they absorb and emit, showed emission lines suggesting many high-energy photons, consistent with Population III predictions. The spectra also suggest that the stars are very large – each on the order of 100 solar masses – and that the masses of the stars meet certain theoretical calculations.
“If Pop III is indeed detected, this is the first detection of these primordial stars,” Visbal told Live Science.
However, JWST was suspected of having seen Population III stars before, the team noted in the study. For example, peer-reviewed research in March 2024 suggested that the telescope had spotted in the galaxy GN-z11 which formed only 430 million years after the universe itself.
The new study, however, argues that the detection of LAP1-B is the only one that meets three theoretical conditions for Population III stars: it formed in a low metallicity environment (hydrogen and helium) with a temperature suitable for star formation; stars formed in low-mass clusters with only a few very large stars present; and the cluster meets the mathematical conditions of the initial mass function, or how the masses of stars were distributed within a population during their formation.
JWST was essential for the observations because its 6.5-meter (21-foot) mirror allows it to capture faint objects at incredible distances, Visbal said. But what helped LAP1-B appear is a phenomenon called gravitational lensing, which occurs when a very massive object, such as a galaxy, bends space-time around it while a background object is in just the right place. When light from the distant background object passes through the “warp” created by the foreground object, the background light is distorted into rings or arcs. This phenomenon is sometimes called Einstein ringbecause it confirms what Einstein suggested more than a century ago.
In this case, LAP1-B became visible when a closer galaxy cluster, called MACS J0416, passed in front of it and “lensed” the light from LAP1-B.
JWST also made it possible to observe the emission lines of stars, which were initially emitted in ultraviolet wavelengths and then stretched into infrared wavelengths due to the expansion of the universe, Visbal said. JWST is optimized for infrared observationsallowing the stars to be visible.
Besides the novelty of finding stars, LAP1-B helps show how galaxies evolved, Visbal said. Because Population III stars are expected to form in small dark matter structures that were also building blocks of larger galaxies, “they teach us about the early stages of galaxy formation and evolution – for example, how metals pollute initially pristine hydrogen and helium.”
