Cybele,

minor planet designation A formal minor-planet designation is, in its final form, a number–name combination given to a minor planet (asteroid, centaur, trans-Neptunian object and dwarf planet but not comet). Such designation always features a leading number (catalog or ...

65 Cybele, is one of the

largest asteroids The following is a collection of lists of asteroids of the Solar System that are exceptional in some way, such as their size or orbit. For the purposes of this article, "asteroid" refers to minor planets out to the orbit of Neptune, and includ ...

in the Solar System. It is located in the outer asteroid belt. It is thought to be a remnant primordial body. It gives its name to the Cybele group of asteroids that orbit outward from the Sun from the 2:1 orbital resonance with Jupiter. The X-type asteroid has a relatively short

rotation period The rotation period of a celestial object (e.g., star, gas giant, planet, moon, asteroid) may refer to its sidereal rotation period, i.e. the time that the object takes to complete a single revolution around its axis of rotation relative to the ...

of 6.0814 hours. It was discovered by

Wilhelm Tempel Ernst Wilhelm Leberecht Tempel (4 December 1821 – 16 March 1889), normally known as Wilhelm Tempel, was a German astronomer who worked in Marseille until the outbreak of the Franco-Prussian War in 1870, then later moved to Italy. Tempel was b ...

in 1861, and named after Cybele, the earth goddess.

Discovery and naming

''Cybele'' was discovered on 8 March 1861, by German astronomer

from the

Marseilles Observatory Marseille Observatory (french: Observatoire de Marseille) is an astronomical observatory located in Marseille, France, with a history that goes back to the early 18th century. In its 1877 incarnation, it was the discovery site of a group of gala ...

in southeastern France. A minor controversy arose from its naming process. Tempel had awarded the honour of naming the asteroid to

Carl August von Steinheil Carl August von Steinheil (12 October 1801 – 14 September 1870) was a German physicist, inventor, engineer and astronomer. Biography Steinheil was born in Ribeauvillé, Alsace. He studied law in Erlangen since 1821. He then studied astronomy i ...

in recognition of his achievements in telescope production. Von Steinheil elected to name it "Maximiliana" after the reigning monarch Maximilian II of Bavaria. At the time, asteroids were conventionally given classical names, and a number of astronomers protested this contemporary appellation. The name Cybele was chosen instead, referring to the

Phrygia In classical antiquity, Phrygia ( ; grc, Φρυγία, ''Phrygía'' ) was a kingdom in the west central part of Anatolia, in what is now Asian Turkey, centered on the Sangarios River. After its conquest, it became a region of the great empires ...

n goddess of the earth. (The previously discovered

45 Eugenia Eugenia ( minor planet designation: 45 Eugenia) is a large asteroid of the asteroid belt. It is famed as one of the first asteroids to be found to have a moon orbiting it. It was also the second triple asteroid to be discovered, after 87 Sylvia ...

54 Alexandra Alexandra ( minor planet designation: 54 Alexandra) is a carbonaceous asteroid from the intermediate asteroid belt, approximately 155 kilometers in diameter. It was discovered by German-French astronomer Hermann Goldschmidt on 10 September 1858, ...

, and 64 Angelina had nevertheless also been given non-classical names; 64 Angelina had also been discovered by Tempel, but its name stood despite similar protests.)

Physical characteristics

The first Cybelian stellar occultation was observed on 17 October 1979, in the Soviet Union. The asteroid appeared to have an irregular shape, with the longest

chord Chord may refer to: * Chord (music), an aggregate of musical pitches sounded simultaneously ** Guitar chord a chord played on a guitar, which has a particular tuning * Chord (geometry), a line segment joining two points on a curve * Chord ( ...

being measured as 245 km, closely matching results determined by the IRAS satellite in 1983 ''(see below)''. During the same 1979 occultation, a hint of a possible 11 km wide minor-planet moon at 917 km distance was detected, but has since never been corroborated. As of 2017, neither the ''Asteroid Lightcurve Data Base'' nor ''Johnstons archive'' consider ''Cybele'' to be a binary asteroid.

Diameter estimates

Mean-diameter estimates for ''Cybele'' range between 218.56 and 300.54 kilometers. According to observations by the Infrared Astronomical Satellite IRAS in 1983, the asteroid has a diameter of 237.26 km. The NEOWISE mission of NASA's Wide-field Infrared Survey Explorer gave a diameter of 218.56 and 276.58 km. The largest estimates of 300.54 km is from the Japanese Akari satellite. In 2004, Müller estimated ''Cybele'' using thermophysical modelling (TPM) to have dimensions of 302 × 290 × 232 km, which corresponds to a mean-diameter of 273.0 km.

Spectrum

Examination of the asteroid's infrared spectrum shows an absorption feature that is similar to the one present in the spectrum of

24 Themis Themis ( minor planet designation: 24 Themis) is one of the largest asteroids in the asteroid belt. It is also the largest member of the Themistian family. It was discovered by Annibale de Gasparis on 5 April 1853. It is named after Themis, th ...

. This can be explained by the presence of water ice. The asteroid may be covered in a layer of fine silicate dust mixed with small amounts of water-ice and organic solids.

Recent occultations

On August 24, 2008, ''Cybele''

occulted An occultation is an event that occurs when one object is hidden from the observer by another object that passes between them. The term is often used in astronomy, but can also refer to any situation in which an object in the foreground blocks ...

2UCAC 24389317, a 12.7- magnitude star in the constellation Ophiuchus which showed a long axis of at least 294 km. On 11 October 2009, ''Cybele'' occulted a 13.4-magnitude star in the constellation

Aquarius Aquarius may refer to: Astrology * Aquarius (astrology), an astrological sign * Age of Aquarius, a time period in the cycle of astrological ages Astronomy * Aquarius (constellation) * Aquarius in Chinese astronomy Arts and entertainment ...

Notes

References

External links

Asteroid Lightcurve Database (LCDB)
query form

)
Dictionary of Minor Planet Names
Google books

at Observatoire de Genève, Raoul Behrend

– Minor Planet Center * * {{DEFAULTSORT:Cybele 000065 Discoveries by Wilhelm Tempel Named minor planets 000065 000065 000065 000065 18610308