A Jupiter-mass object circling a brown dwarf could be the first moon found outside the Solar System - eGamers.io

While studying the CD-35 2722 system, astronomers picked up evidence of a body with a mass of at least one Jupiter. It appears to be orbiting a brown dwarf that weighs approximately 37 Jupiter masses. Should this finding be confirmed, the object would represent the first exomoon ever discovered—a natural satellite beyond our Solar System.

Brown dwarf mystery

Brown dwarfs occupy an unusual category in celestial classification—they are more massive than planets but lack the mass required to sustain nuclear fusion that makes stars shine. This makes the candidate moon particularly intriguing, as its planetary mass combined with its orbit around a brown dwarf rather than a planet creates a unique astronomical phenomenon.

Detection method

The research team utilized the European Southern Observatory's Very Large Telescope and its CRIRES+ instrument to detect the object using the radial velocity method. This technique identifies minuscule changes in the brown dwarf's movement, with the gravitational tug of the orbiting body being the primary evidence of its existence.

Unanswered questions

Two critical questions remain unresolved. First, the object's existence has not yet been definitively confirmed. Second, due to its substantial mass, astronomers are still debating whether it should be classified as a moon or a planet. The research detailing these findings has been published in the journal Nature.