Webb finds brown dwarfs barely twice Jupiter’s mass, challenging star-formation models
Webb has identified brown dwarfs in IC 348 with estimated masses of only about twice Jupiter’s, pushing the known lower boundary of star formation. One of the tiny objects appears to possess a circumstellar disk, raising the possibility that planets could form around an object already comparable in mass to a giant planet. Spectra also reveal an unidentified hydrocarbon associated with the coolest brown dwarfs, prompting astronomers to propose a new “H” spectral class. A stellar nursery 1,000 light-years away has produced objects so small that the boundary between stars and planets is becoming increasingly difficult to define. Deep observations from the James Webb Space Telescope have revealed brown dwarfs in the star-forming region IC 348 with estimated masses of only about twice that of Jupiter. That equals roughly 0.19% of the Sun’s mass and pushes observations into a range where theories struggle to explain how objects can form through the same process that makes stars. The findings were published in The Astrophysical Journal Letters. They build on earlier Webb observations of IC 348 that …
