Dec 13, 2023 - In a groundbreaking discovery, NASA's James Webb Space Telescope team has identified the smallest free-floating brown dwarf ever observed, challenging existing theories of star formation. This tiny celestial object, with only three to four times the mass of Jupiter, was found within the star cluster IC 348, located 1,000 light-years away in the Perseus star-forming region.

What are Brown Dwarfs?

Brown dwarfs, often described as objects straddling the line between stars and planets, form like stars but never reach the temperature and density required for hydrogen fusion. Some are comparable in size to giant planets, with masses only a few times that of Jupiter.

Search Strategy:

Lead author Kevin Luhman, from Pennsylvania State University, and colleague Catarina Alves de Oliveira selected the young star cluster IC 348 for their study. Using Webb's NIRCam and NIRSpec instruments, they identified three intriguing brown dwarf candidates with masses ranging from three to eight times that of Jupiter. The cluster's youth, at just 5 million years old, made the brown dwarfs relatively bright in infrared light.

A Mystery Molecule:

The discovery provides insights into the star-formation process, particularly for objects with masses as small as three to four times that of Jupiter. The team also observed two brown dwarfs exhibiting the spectral signature of an unidentified hydrocarbon – a molecule containing hydrogen and carbon. This marks the first detection of this molecule outside our solar system, challenging existing models for brown dwarf atmospheres.

Brown Dwarf or Rogue Planet?

The newfound brown dwarfs' masses fall within the range of giant planets, sparking a debate about whether they are brown dwarfs or rogue planets ejected from planetary systems. While the team cannot definitively rule out the latter, they argue that the objects are more likely brown dwarfs. The rarity of ejected giant planets and the cluster's young age make it improbable that these celestial bodies were expelled from their original systems.

Future Exploration:

The discovery prompts further exploration to confirm the status of these objects and expand our understanding of the star formation process. Longer surveys may uncover fainter, smaller objects, potentially reaching one Jupiter mass. The ongoing research is part of Guaranteed Time Observation program 1229, and the results have been published in the Astronomical Journal.

NASA's Webb Telescope has once again revolutionized our understanding of the cosmos, uncovering a record-setting free-floating brown dwarf within the star cluster IC 348. As scientists delve into the mysteries surrounding these celestial objects, the discovery raises new questions about the fundamental processes that govern the birth and evolution of stars and planets. Stay tuned for more revelations from the forefront of space exploration with the James Webb Space Telescope.

Source - NASA