What could be the first exomoon orbiting a brown dwarf has been discovered
To date, more than 6,000 exoplanets — planets orbiting a star other than the Sun — have been discovered, but no moon outside the Solar System — known as an exomoon — has ever been definitively identified. Now, a study published in Nature presents evidence of what could be an exomoon orbiting a brown dwarf — an object halfway between a star and a planet. By analysing radial velocity data from observations made by the European Southern Observatory’s (ESO) Very Large Telescope, a team has identified a signal indicating the presence of a satellite with a minimum mass of 0.9 times that of Jupiter and an orbital period of around 170 days. “Although it is unclear whether this exosatellite will meet the criteria—yet to be defined—for being considered an exomoon, it represents an important step towards that first indisputable detection,” the authors state.