James Webb finds cosmic dust factories in the early universe

The James Webb Space Telescope has revealed how metal-poor stars produced cosmic dust in the early universe, a key process for understanding chemical evolution and new star formation, according to a study published in The Astrophysical Journal. Researchers studied Sextans A, a dwarf galaxy 4.6 million light-years away with only 1% to 7% of the Sun's heavy elements, using it as a nearby laboratory for early galactic conditions. Observations with NIRCam and MIRI mapped stars in the asymptotic giant branch phase. About 90% of these stars lacked dust envelopes, but roughly twenty were surrounded by dense dust layers. Models indicate these cosmic factories formed 2,000 to 3,000 million years ago from stars with initial masses around 1.5 times the Sun's.