3 Juno

3 Juno is a large, stony asteroid orbiting the Sun in the main asteroid belt. Karl Ludwig Harding discovered it in 1804.

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Asteroid: A small rocky or metallic body that orbits the Sun and is not classified as a planet or comet. Juno belongs to this broad class of small Solar System bodies.
Orbital elements: The parameters that specify the size, shape, orientation, and timing of an orbit. These parameters describe Juno’s path around the Sun.
Karl Ludwig Harding: A German astronomer who discovered the asteroid 3 Juno in 1804. Harding found Juno while searching for objects in the region between Mars and Jupiter.
Stellar occultation by asteroids: The use of a star's temporary disappearance behind an asteroid to measure the asteroid's position and dimensions. Occultations by Juno can refine its size and shape beyond estimates from brightness alone.
1 Ceres: The largest object in the asteroid belt and a dwarf planet discovered in 1801. Ceres is far larger than Juno and has a distinct dwarf-planet classification.
Main asteroid belt: The region between Mars and Jupiter containing most known asteroids. Juno follows its orbit within this dense population of asteroids.
Orbital resonance: A gravitational relationship in which orbiting bodies exert regular, repeating influences because their orbital periods are related by whole numbers. Resonances with Jupiter can shape the long-term dynamics of bodies in Juno’s region.
Discovery of Ceres: The 1801 discovery of Ceres, the first known object in the asteroid belt. Ceres initiated the sequence of asteroid discoveries that included Juno.
Asteroid photometry: The measurement of sunlight reflected by asteroids to infer their rotation, shape, and surface properties. Photometry turns Juno’s brightness variations into constraints on its physical form.
2 Pallas: A large asteroid discovered in 1802, with an unusually inclined orbit. Pallas shares Juno’s early discovery history but follows a markedly different orbit.