Haumea
Haumea is a dwarf planet in the Kuiper belt whose rapid rotation gives it an unusually elongated shape. It has two moons and a ring.
Rotational flattening: The deformation of a rotating body as centrifugal effects oppose gravity, making it wider at the equator. Haumea spins so rapidly that rotation contributes substantially to its elongated figure.
Dwarf planet: A body orbiting the Sun that is nearly round under its own gravity but has not cleared its orbital neighborhood. This classification places Haumea alongside Pluto, Eris, and other bodies beyond Neptune.
Pluto: A dwarf planet in the Kuiper belt with a large moon, Charon, and a complex system of smaller moons. Pluto is the best-known Kuiper belt dwarf planet, but its shape and rotation differ from Haumea’s.
Michael E. Brown: An American astronomer known for discovering and studying several large trans-Neptunian objects. Brown’s team announced Haumea’s discovery, in a contested history involving another observing group.
Hydrostatic equilibrium: A state in which gravity and internal pressure balance, allowing a body's shape to reflect its rotation and internal structure. Haumea’s shape has been used to assess whether its interior relaxed under self-gravity.
Kuiper belt: A region beyond Neptune containing icy small bodies and dwarf planets. Haumea occupies this distant population of icy Solar System objects.
Eris: A distant dwarf planet in the scattered disc, comparable in size to Pluto. Eris contrasts with Haumea as a large trans-Neptunian dwarf planet without Haumea’s extreme rotation.
José Luis Ortiz Moreno: A Spanish astronomer whose team observed Haumea before its public announcement by another group. Ortiz’s team’s earlier observations became central to the dispute over discovery credit.
Haumea family: A group of Kuiper belt objects with similar orbits and surface properties, thought to share a collisional origin with Haumea. The family is evidence that a major impact helped shape Haumea’s history.
Trans-Neptunian object: An object whose orbit lies partly or wholly beyond Neptune’s orbit. Haumea is one of the largest known members of this broad orbital population.