A tiny galaxy discovered more than 13 billion light-years from Earth may offer the clearest evidence yet of the universe¡¯s earliest stars, according to a recent study by a Japanese-led research team.
An international research team led by researchers from Kanazawa University and the National Astronomical Observatory of Japan used the James Webb Space Telescope to observe an ultra-faint galaxy known as LAP1-B, dating to roughly 800 million years after the Big Bang. The study was published Wednesday in the scientific journal Nature.
The team observed the tiny galaxy using gravitational lensing, a phenomenon in which the gravity of a massive galaxy cluster acts as a lens to magnify the light from a more distant object behind it.
Immediately after the Big Bang, which occurred approximately 13.8 billion years ago, the universe contained only light elements found at the beginning of the periodic table, such as hydrogen, helium and trace amounts of lithium. As these elements gathered together to form stars, nuclear fusion within them gradually produced heavier elements such as carbon, oxygen and iron, which were later scattered across the universe through supernovas.
Astronomers are interested in first-generation stars because they are believed to have produced the first heavy elements in the cosmos, laying the foundations for later generations of stars, planets and eventually life itself. But it has been difficult to see the chemical makeup of the young stars as the earliest galaxies hosting such stars have remained so small and faint.
They determined through the observation that LAP1-B¡¯s oxygen abundance is roughly 1/240 that of the sun.
¡°I was instantly thrilled by the extreme lack of oxygen revealed in the data,¡± said Kimihiko Nakajima, an associate professor at Kanazawa University and leader of the research team. ¡°Finding a galaxy in such a primitive state is astonishing. It¡¯s a chemical signature that clearly indicates a primordial galaxy caught in the moments shortly after its formation.¡±
¡°We hope this discovery marks a historic step in understanding how the elements that make up our own bodies were first born and accumulated across the universe.¡±
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