Using the ESPRESSO instrument on ESO’s Very Large Telescope and the HARPS instrument at ESO’s La Silla 3.6-m telescope, astronomers have detected a sodium cloud close to but slightly out of sync with the hot, Saturn-sized gas-giant exoplanet WASP-49Ab. This artist’s concept depicts a potential volcanic exomoon between WASP-49Ab (left) and its parent star. Image credit: NASA / JPL / Caltech. WASP-49A is a faint Sun-like star discovered by the...