Haumea

Haumea (minor-planet designation 136108 Haumea) is a dwarf planet located beyond Neptune's orbit. It was discovered in 2004 by a team headed by Mike Brown of Caltech at the Palomar Observatory in the United States and independently in 2005, by a team headed by José Luis Ortiz Moreno at the Sierra Nevada Observatory in Spain, though the latter claim has been contested. On September 17, 2008, it was recognized as a dwarf planet by the International Astronomical Union (IAU) and named after Haumea, the Hawaiian goddess of childbirth, though subsequent observations cast doubt on its shape being consistent with hydrostatic equilibrium (and thus perhaps not a dwarf planet). Haumea's mass is about one-third that of Pluto, and 1/1400 that of Earth. Although its shape has not been directly observed, calculations from its light curve indicate that it is a Jacobi ellipsoid, with its major axis twice as long as its minor. Its gravity was until recently thought to be sufficient for it to have relaxed into hydrostatic equilibrium. Haumea's elongated shape together with its rapid rotation and high albedo (from a surface of crystalline water ice), are thought to be the consequences of a giant collision, which left Haumea the largest member of a collisional family that includes several large trans-Neptunian objects (TNOs) and Haumea's two known moons, Hiʻiaka and Namaka. Haumea is currently the third-largest known trans-Neptunian object, after Eris and Pluto. Two teams claim credit for the discovery of Haumea. Mike Brown and his team at Caltech discovered Haumea in December 28, 2004 on images they had taken on May 6, 2004. On July 20, 2005, they published an online abstract of a report intended to announce the discovery at a conference in September 2005. At around this time, José Luis Ortiz Moreno and his team at the Instituto de Astrofísica de Andalucía at Sierra Nevada Observatory in Spain found Haumea on images taken on March 7–10, 2003. Ortiz emailed the Minor Planet Center with their discovery on the night of July 27, 2005. Brown initially conceded discovery credit to Ortiz, but came to suspect the Spanish team of fraud upon learning that his observation logs were accessed from the Spanish observatory the day before the discovery announcement. These logs included enough information to allow the Ortiz team to precover Haumea in their 2003 images, and they were accessed again just before Ortiz scheduled telescope time to obtain confirmation images for a second announcement to the MPC on July 29. Ortiz later admitted he had accessed the Caltech observation logs but denied any wrongdoing, stating he was merely verifying whether they had discovered a new object. Precovery images of Haumea have been identified back to March 22, 1955. IAU protocol is that discovery credit for a minor planet goes to whoever first submits a report to the MPC (Minor Planet Center) with enough positional data for a decent determination of its orbit, and that the credited discoverer has priority in choosing a name. However, the IAU announcement on September 17, 2008, that Haumea had been accepted as a dwarf planet, did not mention a discoverer. The location of discovery was listed as the Sierra Nevada Observatory of the Spanish team, but the chosen name, Haumea, was the Caltech proposal; Ortiz's team had proposed 'Ataecina', named for the ancient Iberian goddess of Spring. Until it was given a permanent name, the Caltech discovery team used the nickname 'Santa' among themselves, because they had discovered Haumea on December 28, 2004, just after Christmas. The Spanish team were the first to file a claim for discovery to the Minor Planet Center, in July 2005. On July 29, 2005, Haumea was given the provisional designation 2003 EL61, based on the date of the Spanish discovery image. On September 7, 2006, it was numbered and admitted into the official minor planet catalogue as (136108) 2003 EL61. Following guidelines established by the IAU that classical Kuiper belt objects be given names of mythological beings associated with creation, in September 2006 the Caltech team submitted formal names from Hawaiian mythology to the IAU for both (136108) 2003 EL61 and its moons, in order 'to pay homage to the place where the satellites were discovered'. The names were proposed by David Rabinowitz of the Caltech team. Haumea is the matron goddess of the island of Hawaiʻi, where the Mauna Kea Observatory is located. In addition, she is identified with Papa, the goddess of the earth and wife of Wākea (space), which, at the time, seemed appropriate because Haumea was thought to be composed almost entirely of solid rock, without the thick ice mantle over a small rocky core typical of other known Kuiper belt objects. Lastly, Haumea is the goddess of fertility and childbirth, with many children who sprang from different parts of her body; this corresponds to the swarm of icy bodies thought to have broken off the dwarf planet during an ancient collision. The two known moons, also believed to have formed in this manner, are thus named after two of Haumea's daughters, Hiʻiaka and Nāmaka.