Overview
- A team led by Kevin Hoy published a Nature paper on July 22 reporting radial‑velocity measurements from ESO’s VLT that reveal a roughly 170‑day wobble of the brown dwarf CD‑35 2722 b consistent with a companion at least about 0.9 times Jupiter’s mass.
- The result rests on repeated CRIRES+ spectra taken from October 2023 through February 2026 and gives a minimum mass (M sin i) so the object’s true mass and inclination remain uncertain.
- Authors use the neutral term “exosatellite,” but the finding collides with the IAU’s 2018 wording that would classify a planet‑mass body orbiting a brown dwarf as an exoplanet, leaving nomenclature and taxonomy unresolved.
- Scientists say the system bears on formation theories because the companion’s mass, close orbit and youth favor direct gravitational collapse over satellite core accretion though alternative scenarios, including a binary brown‑dwarf interpretation, have not been ruled out.
- Teams plan follow‑up with complementary methods — astrometry, direct imaging, transit searches and targeted JWST and future ELT and PLATO observations — to measure inclination, confirm the object’s nature and probe how such worlds form.