Haumea (dwarf planet)

( 136 108 ) Haumea is a dwarf planet, the subclass of Plutoiden and is among the largest known objects in the Kuiper Belt. Due to their fast rotation, it has at a distance of the poles of only about 1100 km is an ellipsoidal shape with a strong equatorial diameter of about 2200 km.

Discovery

The discovery of Haumea was announced on 28 July 2005 by JL Ortiz, FJ Aceituno, P. Santos Sanz from the Sierra Nevada Observatory in Spain after re- evaluation of recordings of 7 March 2003, after July 20, 2005, the Working Group by Mike Brown had announced a conference fee to the object under the working name K40506A in the United States at Caltech. The observations of Ortiz found with a standard Schmidt- Cassegrain telescope instead of a main mirror of 35 cm diameter, as it is also used by amateur astronomers. The group was able to start out with just three days the object. Later, the object could also be found on archival footage, including on images from the Palomar Observatory Sky Survey from the year 1955. Due to this additional data safe orbit determination was possible, so that the discovery was made public on 28 July 2005. Because of unresolved doubt caused by the fact that the Ortiz group before the reported discovery had downloaded and evaluated from the Internet, the observation data of the group to Mike Brown, without pointing out, the discoverers name, the Minor Planet Center provisional restoration from its list deleted.

Controversy surrounding the discovery

Mike Brown, Chad Trujillo and David Rabinowitz of the California Institute of Technology found the object on 28 December 2004 at the Palomar Observatory. The research group led by Mike Brown used for the object, the unofficial working title " Santa ". Because of the publication of the discovery of Haumea ( ex. 2003 EL61 ) by the Spanish astronomers announced the discovery of the group to Brown two even larger trans-Neptunian objects ( 136199 ) Eris ( ex. 2003 UB313, Xena ) and ( 136472 ) Makemake ( ex. FY9 2005 ) only a few hours later at a press conference.

Brown and his group recognized initially Ortiz et al. as the discoverer of ( 136 108 ) Haumea, until it turned out that Ortiz et al. had access to publicly available on the Internet telescopic log of the group to Brown before the group to Ortiz made ​​known the discovery. While the accusation was in the room that the Spanish group had only found the object using this data on their recordings from 2003, insisted Ortiz to have only checked if it is the announced under the working name K40506A object of Brown et al. acted by the same celestial body, which his group had found independently. Brown's group then threw the group to Ortiz in breach of the rules of scientific ethics and demanded by the Minor Planet Center (MPC ), Ortiz et al. deprive the state of the discoverer.

The controversy stems from the fact that according to the applicable rules of the International Astronomical Union, the discovery of an asteroid or dwarf planet is awarded to those observers who submit the first enough position measurements to the MPC to determine the orbit of the object in the solar system with sufficient accuracy. While the group around Haumea Brown has found the end of 2004, but kept the discovery secret. The group, however, Ortiz sent its observations on 28 July 2005 to the MPC. The Sierra Nevada Observatory is therefore headed by the MPC as the discoverer.

Name

On 17 September 2008 was 2003 EL61 named by the International Astronomical Union, following a proposal Browns after the Hawaiian goddess Haumea. At the same time Haumea was recognized as the fifth dwarf planet in the solar system, and thus also as the fourth Plutoid. The proposed name of Ortiz was Ataecina, after the name of a revered in pre-Roman period in the Iberian Peninsula deity.

Orbit

( 136 108 ) Haumea runs on an elliptical orbit in 285 years of the sun. The perihelion is about 35 AU from the Sun, the aphelion around 51 AU. The orbital plane is inclined 28 ° to the ecliptic.

Size and composition

From the orbital motion of the larger of the two moons (see below) was the mass of ( 136 108 ) Haumea be determined with high reliability at 3.9 × 1021 kg, which corresponds to 30 % of the mass of ( 134340 ) Pluto. From the observed light curve can be concluded that the object rotates in only 3.9154 hours on its own axis: ( 136 108 ) Haumea rotates faster than any other known object in the solar system with a size of more than 100 km. The observed light changes can also lead to the conclusion that the object has assumed an elliptical shape due to the rapid rotation: It is assumed that the shape is a triaxial ellipsoid whose length is estimated to be about 2200 ± 200 km and its short axis only is half as large.

The rapid rotation of Haumea is explained by the formation by the collision of two dwarf planets. Accordingly, the original celestial body to be in conflict with a 1000 km long object. A large part of the ice shell was blown away by the collision, so Haumea has a significantly higher density than other Kuiper belt objects. From the fragments of the collision is not only the two moons, but also other small objects, with Haumea form together a family of celestial bodies emerged. The apparent magnitude is 17.3 m while the opposition.

Spectroscopic observations at the Keck and Gemini Observatory on show traces of water ice on the surface of ( 136 108 ) Haumea. Haumea was confirmed as a dwarf planet because it is despite their widely different from the spherical shape form with a high likelihood of hydrostatic equilibrium.

Monde

Observations using adaptive optics at the Keck Observatory have shown that ( 136 108 ) Haumea is orbited by two moons. The larger of the two, Hiiaka runs at a orbital eccentricity of 0.0513 in the average distance of 49,880 km in about 49.5 days around the dwarf planet. The smaller, Namaka, has a distance of 25,657 kilometers, its orbital period is 18.3 days. The orbital planes of the moons are about 13 ° tilted against each other, their masses are estimated at about 1 % and 0.2 % of the mass of ( 136 108 ) Haumea.

In the Hawaiian mythology are Hiiaka and Namaka daughters of the fertility goddess Haumea, which originated from different parts of the body Haumeas. The names of the moons thus play on their predicted emergence as fragments Haumeas after the collision with another object.