The Hubble Space Telescope has been used to study Ganymede, the largest Jupiter’s moon, and in particular its aurorae. Analyzing their characteristics, it was possible to get the best clues found so far of the existence of a Ganymede underground ocean of liquid salt water. This ocean may contain more water than it exists on the surface of the Earth.
SPHERE (Spectro-Polarimetric High-contrast Exoplanet REsearch) is an instrument built especially to take direct pictures of exoplanets but the first scientific article based on its observations was about the binary system V471 Tauri. A group of astronomers led by Adam Hardy carried out this research, published in the journal “Astrophysical Journal Letters”, explaining why it led to a surprise.
The astronomers expected that there was a brown dwarf orbiting this double star but SPHERE didn’t find anything. It’s a surprising result because the presence of a brown dwarf was by far the most plausible explanation for the strange behavior of V471 Tauri.