Possible First Stars: JWST Identifies GLIMPSE-16043 as a Leading Population III Candidate

GLIMPSE-16043 — a candidate for the universe’s first stars

GLIMPSE-16043 is a tiny, gravitationally lensed dwarf galaxy that a team of astronomers has flagged as a strong candidate for hosting Population III stars — the hypothesized first generation of stars formed from primordial hydrogen and helium.

Why this matters

The Big Bang produced mostly hydrogen and helium (with trace lithium and beryllium). Heavier elements such as carbon, oxygen and iron were forged later inside stars and dispersed by supernovae. Astronomers classify later, metal-enriched stars as Population I and II; the first, metal-free generation is called Population III. Detecting such a population would illuminate the earliest stages of star and galaxy formation and the origin of the elements that make planets and life possible.

How GLIMPSE-16043 was found

The discovery team searched thousands of gravitationally lensed galaxies imaged by the James Webb Space Telescope (JWST). A foreground galaxy magnifies GLIMPSE-16043’s light, making this otherwise faint object visible. The researchers selected candidates that appeared redder in certain filters — a signature of strong hydrogen emission or rest-frame ultraviolet shape at high redshift — and estimated ages from multi-filter photometry. They kept objects whose photometric ages fell in the expected window for Population III systems: roughly 700 million to 1.2 billion years after the Big Bang.

What the observations show

GLIMPSE-16043 sits at an epoch of about 900 million years after the Big Bang and shows little to no detectable metals based on current broad-band imaging and photometric modeling. As a small, nearly point-like, hydrogen-dominated source in JWST images, it fits the expected profile for a late-surviving Population III candidate.

Limitations and next steps

Confirming Population III status requires spectroscopy to detect (or tightly constrain) metal lines and to measure the galaxy’s redshift and ionization state precisely. GLIMPSE-16043 is extremely faint; current JWST imaging with broad filters provides strong hints but lacks the spectral resolution and signal-to-noise to make a definitive chemical measurement. Future deep spectroscopy with JWST’s spectrographs (pushing integration times) or next-generation ground- and space-based observatories (for example, ELT-class telescopes and more sensitive instruments) will be needed to confirm whether this object truly lacks metals.

Conclusion

If GLIMPSE-16043 is confirmed as a Population III system, it would be one of the rare surviving examples of the universe’s first stars and a key probe of early cosmic chemistry and galaxy formation. For now, it remains a compelling candidate that invites deeper spectroscopic follow-up.