|Hygiea, image of the Very Large Telescope (VLT) of the European Southern Observatory in Chile|
|Properties of the orbit ( animation )|
|Orbit type||Main outer belt asteroid|
|Asteroid family||Hygiea family|
|Major semi-axis||3.142 AU|
|Perihelion - aphelion||2.788 AU - 3.495 AU|
|Inclination of the orbit plane||3.8 °|
|Length of the ascending node||283.2 °|
|Argument of the periapsis||312.3 °|
|Time of passage of the perihelion||December 18, 2016|
|Sidereal period of rotation||5 a 207 d|
|Mean orbital velocity||16.75 km / s|
|Medium diameter||434 ± 14 km|
|Dimensions||500 × 385 × 350|
|Dimensions||(8.32 ± 0.8) 10 19 kg
≈ 9 10 19 kg
|Medium density||2.6 g / cm³|
|Rotation period||13.82559 ± 0.00005 h|
|Absolute brightness||5.4 likes|
(according to Tholen)
(according to SMASSII)
|Explorer||Annibale De Gasparis|
|Date of discovery||April 12, 1849|
|Source: Unless otherwise stated, the data comes from JPL Small-Body Database Browser . The affiliation to an asteroid family is automatically determined from the AstDyS-2 database . Please also note the note on asteroid items.|
(10) Hygiea (former name (10) Hygieia ) is the third largest asteroid and fourth largest celestial body in the main belt after Pallas and Vesta with a mean diameter of 434 kilometers . It is approximately spherical in shape and is probably in hydrostatic equilibrium , which means that it fulfills the criteria for classification as a dwarf planet candidate .
Discovery and naming
Hygiea was discovered on April 12, 1849 by the then 29-year-old Italian astronomer Annibale De Gasparis at the observatory in Naples and was named by the head of the observatory after Hygieia , the goddess of health and daughter of the Greek mythological god Asclepius . Her astronomical symbol is the Aesculapian staff .
Orbit and rotation
Hygiea orbits the sun in 5 years, 6 months and 24 days on an elliptical orbit between 2.79 AU and 3.49 AU from its center. The eccentricity of the orbit is slightly higher than that of the Ceres or Vesta at 0.112 , the orbit is 3.83 ° inclined to the ecliptic . In the aphelion , the asteroid is located on the outermost edge of the main belt. Based on light curve observations in 2017 and 2018, Hygiea rotates once around its axis in 13 hours and 49.5 minutes. The axis of rotation is inclined by 60 ° in relation to the orbit.
Size and mass
According to new findings from the European Southern Observatory in Chile, Hygeia, with an equivalent diameter of around 434 km and the almost spherical shape of a Maclaurin ellipsoid, meets all the criteria for being classified as a dwarf planet . The observations were made with the SPHERE instrument on the Very Large Telescope (VLT). The mass of the asteroid was determined in the course of this investigation to be about 8.3 · 10 19 kg.
Spectroscopic examinations showed that the chemical composition of Hygiea shows striking similarities with the carbonaceous meteorites Warrenton and Ornans . It is possible that Hygiea is the original body of these meteorites.
- MA Barucci, E. Dotto, JR Brucato, TG Müller, P. Morris, A. Doressoundiram, M. Fulchignoni, MC de Sanctis, T. Owen, J. Crovisier: 10 Hygiea: ISO infrared observations . In: Icarus . tape 156 , no. 1 . Elsevier, 2002, p. 202-210 .
- P. Vernazza, L. Jorda, JL Maestre: A basin-free spherical shape as an outcome of a giant impact on asteroid Hygiea. Nature Astronomy (October, 2019)
- ESO : ESO telescope reveals possibly smallest known dwarf planet in the solar system October 28, 2019
- scinexx.de: Smallest dwarf planet in the solar system detected October 30, 2019
- P. Vernazza, L. Jorda, P. Ševeček et al: A basin-free spherical shape as an outcome of a giant impact on asteroid Hygiea . In: Nature Astronomy . October 28, 2019. bibcode : 2019NatAs.tmp..477V . doi : 10.1038 / s41550-019-0915-8 .
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- AO Leuschner: Comparison of Theory with Observation for the Minor planets 10 Hygiea and 175 Andromache with Respect to Perturbations by Jupiter . In: National Academy of Sciences (Ed.): Proceedings of the National Academy of Sciences . 8, No. 7, July 15, 1922, pp. 170-173. bibcode : 1922PNAS .... 8..170L . doi : 10.1073 / pnas.8.7.170 . PMID 16586868 . PMC 1085085 (free full text).
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- ESO telescope reveals what is possibly the smallest known dwarf planet in the solar system. ESO, October 28, 2019, accessed December 26, 2019 .