​In a groundbreaking set of observations, the James Webb Space Telescope (JWST) has identified surprising mechanisms of dust creation in the dwarf galaxy Sextans A. Located about 4 million light-years away, this chemically primitive galaxy resembles conditions shortly after the Big Bang, when the cosmos was largely composed of hydrogen and helium.

Stars in the final stage of their life shed material into space and help seed galaxies with dust. Until now, scientists believed that dying stars in chemically primitive galaxies could only produce simple dust like silicon carbide or soot.

MIRI's sensitive infrared vision has changed this, revealing a star producing metallic iron dust. This is the first time iron-bearing dust has been detected in such a metal-poor environment, where heavy elements are scarce.

MIRI revealed aging stars, a stage our own Sun will eventually reach, producing unexpected dust types, including metallic iron and silicon carbide, materials thought to require richer environments.

These discoveries challenge old ideas that only supernovae could make dust. Instead, aging stars like these may have been key contributors, creating a diverse mix of dust types in the early Universe, helping form planets and galaxies sooner than expected.

Dr Olivia Jones, Webb Fellow at UK ATC and co-author on this study, said: “You've probably heard the saying, 'We are all made of stardust.' These new results from the James Webb Space Telescope show just how true this is. They reveal that even in the Universe's earliest, most primitive galaxies, stars were already forging the complex building blocks of planets, atmospheres and life itself."​

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