Summary
Using the Near-Infrared Imager and Slitless Spectrograph (NIRISS) instrument on the NASA/ESA/CSA James Webb Space Telescope, astronomers have discovered six new free-floating planetary-mass members of NGC 1333 with estimated masses between 5 and 15 times the mass of Jupiter.
NGC 1333 is a star-forming cluster located some 1,000 light-years away in the northern constellation of Perseus.
Only 1-3 million years old, NGC 1333 hosts about half as many brown dwarfs as stars, a higher proportion than seen before.
The observations revealed 19 known brown dwarfs and 6 free-floating planetary-mass objects between 5 and 10 times more massive than Jupiter.
The JWST/NIRISS Deep Spectroscopic Survey for Young Brown Dwarfs and Free-Floating Planets.