Hygiea was long believed to be a large asteroid in the asteroid belt, but has met all the requirements needed to become a dwarf planet thanks to new observations made by Chile’s Very Large Telescope (VLT).
Thanks to the unique capability of the SPHERE instrument on the VLT, which is one of the most powerful imaging systems in the world, we could resolve Hygiea’s shape, which turns out to be nearly spherical,” Vernazza, an astronomer said in a media statement. “Thanks to these images, Hygiea may be reclassified as a dwarf planet, so far the smallest in the Solar System.”
Hygiea is just over 267 miles in diameter. To put it in context, Pluto, which is the most famous dwarf planet, is roughly 1,491 miles in diameter. Hygiea would be the smallest dwarf planet with a rotation rate of around 13.8 hours. One surprising finding was that it lacked an impact crater. Hygiea is the main member of one of the largest asteroid families that originated from the same parent body. Astronomers believe that the family of nearly 7,000 asteroids was created by a large impact that sent debris from Hygiea into an asteroid swarm about two billion years ago. While Vernazza and his team identified two unambiguous craters, neither of them could have been caused by the impact. “Neither of these two craters could have been caused by the impact that originated the Hygiea family of asteroids whose volume is comparable to that of a 100 km-sized object,” the study’s co-author Miroslav Brož of the Astronomical Institute of Charles University in Prague, Czech Republic., said in a media statement. “They are too small.”
The finding is an exciting one for astronomers all around the world.
Hygiea’s potential reclassification speaks to its gravitational pull Any object with enough self-gravity to pull itself into a spherical shape has the potential to be considered a ‘dwarf planet’. “As we explore more and more objects in the asteroid belt and beyond, we are finding objects that surprise us. It is why we explore the cosmos but there is still much to discover in the solar system itself…..