Astronomers are buzzing with excitement! The James Webb Space Telescope (JWST) might have spotted the universe’s first stars, known as Population III or POP III stars, in a distant galaxy called LAP1-B. These stars are crucial because they were born shortly after the Big Bang, around 800 million years later. That’s 13 billion years ago! What we see now is how LAP1-B looked back then.
Eli Visbal, a scientist from the University of Toledo, shared that this could be our first glimpse of such ancient stars. “To discover POP III stars, we really needed the sensitivity of JWST and the 100 times magnification from a galaxy cluster in between,” he explained. This cluster, known as MACS J0416.1-2403, is about 4.3 billion light-years away and helped magnify the light from LAP1-B, thanks to a phenomenon called gravitational lensing that Einstein predicted back in 1915.
During this time, called “the epoch of reionization,” the first stars were changing the universe’s neutral gas into plasma. This marked the end of the so-called “cosmic dark ages.” POP III stars formed around 200 million years after the Big Bang, when the universe was cooling enough for hydrogen atoms to form. These stars played a key role in the early stages of galaxy formation. “They help us understand how galaxies evolved and can even tell us about dark matter,” said Visbal.
Finding these ancient stars hasn’t been easy. They tend to form in small clusters and are faint, making them hard to detect. Visbal noted, “They are elusive because they are very far away and mostly in small groups.” These stars are also interesting because they have low metallicity, meaning they lack heavier elements. This allows them to grow to enormous sizes—up to 100 times that of our Sun.
Interestingly, because primordial gas cools less efficiently, there’s less fragmentation during their formation. This results in more massive stars compared to their metal-rich younger counterparts. In LAP1-B, scientists found stars surrounded by gas with minimal metals, likely in groups of around 1,000 solar masses.
The team’s belief is that gravitational lensing can help discover more POP III stars. “We were surprised to find they should be common enough to observe behind a cluster like MACSJ0416,” Visbal said. Future studies will focus on how these stars transition to the next generation, Pop II stars, to link their characteristics with the spectrum of LAP1-B and similar galaxies.
The findings were recently published in The Astrophysical Journal Letters. These discoveries not only pique our curiosity but also lay the groundwork for understanding the cosmos. The exploration of deep space continues to reveal secrets about our universe’s origins!
