Featured Image: Low-Mass Brown Dwarfs in a Class of Their Own?
The glowing green nebula in this JWST image surrounds the star cluster
IC 348, which is the subject of a recent study by Kevin Luhman (Penn
State University) and Catarina Alves de Oliveira (European Space
Agency). Using JWST’s Near-Infrared Camera, Luhman and Alves de Oliveira
searched the cluster’s young stellar population for free-floating brown
dwarfs — objects that are less massive than stars but more massive than
most planets — and discovered multiple candidates with masses down to
just twice the mass of Jupiter. Follow-up JWST spectroscopy confirmed
the masses of these objects, making them the lowest-mass brown dwarfs
known to date. In addition to their mass, these newly discovered brown
dwarfs are remarkable because their spectra show evidence of hydrocarbon
molecules, the exact identities of which are not yet known. Luhman and
Alves de Oliveira proposed that low-mass brown dwarfs bearing this
chemical signature be inducted into a new spectral class called “H” for
“hydrocarbon.” To add to the intrigue of these objects, the authors also
discovered signs of circumstellar disks around two of them, suggesting
that they may be capable of forming and harboring planets. To learn more
about the low-mass brown dwarfs in IC 348, be sure to check out the
full research article linked below.
By Kerry Hensley
Citation
“A New Spectral Class of Brown Dwarfs at the Bottom of the IMF in IC 348,” K. L. Luhman and C. Alves de Oliveira 2025 ApJL 986 L14.
doi:10.3847/2041-8213/addc55
