This is the best view yet of asteroid Hygiea in the main asteroid belt, from ESO’s Very Large Telescope (VLT). Hygiea is now seen to be nearly spherical, meaning it could possibly be classified as a dwarf planet. Image via ESO/P. Vernazza et al./MISTRAL algorithm (ONERA/CNRS).
The dwarf planets in our solar system are intriguing worlds, not large enough to be full-fledged planets, yet still distinct from asteroids. Eris and Pluto are the largest known of our solar system’s dwarf planets, and Ceres is the smallest of the current five official dwarf planets. But now there is a new contender for smallest dwarf planet: Hygiea.
Hygiea is the fourth largest object in the main asteroid belt between Mars and Jupiter, after Ceres (which is also counted as an asteroid), Vesta and Pallas. However, new observations from the European Southern Observatory’s (ESO) Very Large Telescope (VLT) – using the SPHERE instrument – suggest that it should be classified as a dwarf planet. The new peer-reviewed results were published on October 28, 2019, in Nature Astronomy. SPHERE is used primarily for taking images of larger exoplanets around other stars.
Hygiea was already known to have three of the four characteristics of dwarf ...