James Webb Space Telescope May Have Spotted the Universe’s First Stars, Astronomers Say

NASA's James Webb Space Telescope (JWST) is peering back to the cosmic dawn. Astronomers report it may have at last observed the universe's first stars — the elusive “Population III” stars born from pure hydrogen and helium soon after the Big Bang. For decades, astronomers have sought these cosmic relics. These primordial objects would signal the end of the cosmic dark ages. They could also teach us more about how the earliest galaxies formed.

Clues of Population III Stars

According to the findings published in The Astrophysical Journal Letters, a team led by astronomer Eli Visbal reported evidence of Pop III stars in the galaxy LAP1-B, seen ~800 million years after the Big Bang. Webb's infrared spectrum shows its stars emit intense ultraviolet light, and each is roughly 100 times the Sun's mass. The surrounding gas is nearly metal-free, consistent with first-generation stars. “If indeed Pop III, this is the first detection of these primordial stars,” Visbal said.

Webb Surveys the Cosmic Dawn

Extremely distant and faint galaxies are spotted by Webb using its 6.5-meter mirror and infrared cameras. A foreground cluster (MACS J0416) served as a cosmic lens and magnified the light of a distant galaxy up to about 100x times. These are instruments that allowed Webb to see the universe some 800 million years after the Big Bang.

Population III stars were formed from pure hydrogen and helium, with virtually no heavy metal elements, and had a lifespan of just a few million years, which made them incredibly difficult to detect. The sensitivity and lensing of Webb now provide the astronomers with an opportunity to discover these ancient objects.