Planet or Star? Webb Redefines Cosmic Boundaries

Using the James Webb Space Telescope, scientists have analyzed 29 Cygni b, a massive object with fifteen times the mass of Jupiter. Despite its size, its heavy-element composition and orbital alignment reveal a planetary origin.

The findings confirm that it formed through accretion in a protoplanetary disk, rather than as a star via gas cloud collapse. This challenges existing classifications and helps define the upper limits of planet formation.

The study offers new insight into how the largest worlds emerge—blurring the boundary between planets and stars and reshaping our understanding of cosmic evolution.

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