Английская Википедия:65489 Ceto

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Шаблон:Short description Шаблон:Infobox planet

65489 Ceto, as a binary also (65489) Ceto/Phorcys,[1] is a binary trans-Neptunian object (TNO) discovered on March 22, 2003, by Chad A. Trujillo and Michael Brown at Palomar. It is named after the sea goddess Ceto from Greek mythology. It came to perihelion in 1989.[2]

Physical characteristics

Файл:65489 Ceto.tiff
Polar view of Ceto's orbit

65489 Ceto is an example of a close binary TNO system in which the components are of similar size. Combined observations with the infrared Spitzer Space Telescope and the Hubble Space Telescope allow the diameter of Ceto itself to be estimated at Шаблон:Val and the diameter of Phorcys at Шаблон:Val, assuming equal albedo for both components.[1]

The binary nature of Ceto enables direct calculation of the system mass, allowing estimation of the masses of the components and providing additional constraints on their composition. The estimated density of Ceto is Шаблон:Val, significantly less than that of the large TNOs (Haumea: Шаблон:Val, Eris: 2.26, Pluto: 2.03, Charon: 1.65) but significantly more than that of smaller TNOs (e.g. Шаблон:Val for Шаблон:Mpl). Phorcys has a mass of about Шаблон:Val.[1] Unless the bodies are porous, the density is consistent with rock–ice composition, with rock content around 50%.[1]

It has been suggested that tidal forces, together with other potential heat sources (e.g. collisions or 26Al decay) might have raised the temperature sufficiently to crystallise amorphous ice and reduce the void space inside the object. The same tidal forces could be responsible for the quasi-circular orbits of the components of Ceto.[1]

Ceto is listed on Michael Brown's website as possibly a dwarf planet.[3]

Satellite

Шаблон:Infobox planet

Ceto's satellite was identified as a binary on April 11, 2006, by K. Noll, H. Levison, W. Grundy and D. Stephens using the Hubble Space Telescope; the object was named Phorcys, formally (65849) Ceto I Phorcys, after the Greek sea god. Using an extended definition of a centaur as an object on a non-resonant (unstable) orbit with its perihelion inside the orbit of Neptune,[4] the Ceto system can be considered the second known binary centaur.[1]

Phorcys's diameter has been estimated to be Шаблон:Val[5] and Шаблон:Val.[1]

See also

References

Шаблон:Reflist

External links

Шаблон:Minor planets navigator Шаблон:Small Solar System bodies Шаблон:Authority control

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  3. Шаблон:Cite web
  4. Шаблон:Cite journal
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