Overview
- The discovery was published Wednesday in Nature after 23 radial‑velocity measurements made with the VLT’s CRIRES+ between October 2023 and February 2026 that revealed a repeating 170‑day wobble of the brown dwarf.
- Modeling gives the companion a minimum mass about 90 percent of Jupiter and the host brown dwarf a mass near 30–37 Jupiters, which implies a host‑to‑satellite mass ratio of roughly 2.5 percent.
- The team calls the object an “exosatellite” and describes it as a strong candidate rather than a confirmed exomoon because current data provide only minimum mass and lack orbital inclination.
- Authors and outside experts say the signal must be checked with astrometry and direct imaging to measure the true mass and orbit, tasks that the ELT and further VLT monitoring could enable.
- If confirmed, the finding would open a new way to find moon‑like companions, force work on formation models for massive satellites, and prompt the community to refine how it defines moons versus planets.