Webb Finds Brown Dwarfs Barely Twice Jupiter’s Mass, Challenging Star-Formation Models

Where does a planet end and a star begin? Webb found a free-floating brown dwarf only about twice Jupiter’s mass, surrounded by a disk of planet-forming material — an object with a planet’s mass that appears to have formed like a star.

Webb spectroscopy identifies a roughly two-Jupiter-mass IC 348 member with infrared excess from a disk, while spatial evidence favors star-like formation over planetary ejection.

Webb finds brown dwarfs barely twice Jupiter’s mass, challenging star-formation models

Webb finds brown dwarfs only twice Jupiter’s mass, pushing star formation into a realm once associated mainly with planets.

JWST found brown dwarfs at 2 Jupiter masses and a molecule no model predicted

A panoramic JWST survey of IC 348, a star-forming region 1,000 light-years away, has confirmed brown dwarfs barely twice the mass of Jupiter — the lightest ever spectroscopically verified. Eight carry an atmospheric compound no model predicted. The discovery breaks the theoretical minimum for stellar formation and proposes a new spectral class.