10 Hygiea

10 Hygiea is a large, nearly spherical asteroid in the main asteroid belt, discovered in 1849 and named after Hygieia, the Greek goddess of health.

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Asteroid belt: The region between Mars and Jupiter containing most of the Solar System’s known asteroids. Hygiea orbits within this broad population of rocky and metallic bodies.
Asteroid rotation: The spinning motion of an asteroid, measured through changes in its brightness or resolved images. Hygiea’s rotation period helps constrain its shape and internal structure.
Annibale de Gasparis: An Italian astronomer who discovered several asteroids, including 10 Hygiea. De Gasparis discovered Hygiea in Naples in 1849.
Ceres: The largest object in the asteroid belt and the only dwarf planet located there. Ceres is larger and officially classified as a dwarf planet, unlike Hygiea.
C-type asteroid: A dark asteroid type rich in carbon-bearing materials and common in the outer asteroid belt. Hygiea’s low reflectivity and spectrum identify it as a carbon-rich C-type body.
Light curve: A record of an object's brightness over time, used to infer rotation and shape. Brightness variations helped astronomers determine Hygiea’s spin and elongated shape before direct imaging.
Discovery of 10 Hygiea: The 1849 identification of the asteroid 10 Hygiea by Annibale de Gasparis. The discovery made Hygiea the tenth asteroid identified.
Pallas: A large asteroid in the main belt, notable for its high orbital inclination. Pallas is comparable in size but markedly less spherical than Hygiea.
Hydrostatic equilibrium: A state in which gravity and internal pressure balance, allowing a body to assume a rounded shape. Hygiea’s near-spherical shape suggests gravity has rounded it despite its modest size.
Adaptive optics: A technique that corrects atmospheric distortion to sharpen telescope images. Adaptive-optics observations resolved Hygiea’s surface and revealed its unusually round outline.