(65489) Ceto
Template: Infobox Asteroid / Maintenance / Error 2
( 65489 ) Ceto is a transneptunisches object that is classified as SDO and as a centaur. Since Ceto has a large companion called Phorcys, this system can also be understood as a double asteroid system.
- 3.1 Size / surface
- 3.2 Internal structure
Discovery and designation
Ceto was discovered on 22 March 2003 by a team of astronomers from the California Institute of Technology in Pasadena consisting of Mike Brown and Chad Trujillo as part of the NEAT program at Palomar Observatory. The asteroid first received the provisional designation 2003 FX128.
On November 23, 2006 together with the systems Typhon / Echidna and Logos / Zoe, Ceto and Phorcys were by the International Astronomical Union ( IAU) officially named after the sea monster Keto from Greek mythology, who with her brother Phorkys the Gorgons, the Graiai and Echidna and Ladon gave birth. Mainly it is famous because of their monstrous offspring.
Web properties
Orbit
Ceto and Phorcys orbiting the sun on a prograde, highly elliptical orbit between 2.655938 billion km ( 17.754 AU) and 27,409,638,000 km ( 183.222 AE) distance from its center. The orbital eccentricity is 0.823, the orbit is tilted 22.305 degrees to the ecliptic. Therefore, the highly eccentric orbit of the system runs in its perihelion, which it reached in 1989, well within the orbit of Uranus, while at aphelion after about 500 years of traversing the entire Kuiper belt 6 times the distance of Neptune and 2.4 -fold Apheldistanz Pluto reached by the sun. His next perihelion would have to make the system reach around the year 2996.
The orbital period of Ceto is 1007.35 years or 367,933 days, 17 hours, 44 minutes and 22 seconds.
Rotation
Ceto rotates in 4 hours and 25.8 minutes once on its axis. It follows that she performs in a Ceto - year 1.99332 million own twists ( "days" ).
Physical Properties
Size / surface
Ceto has a diameter of 223 km, based on an assumed albedo of 5.8%. The surface is so very dark. Their diameter was previously estimated to be 174 km.
Internal construction
The binary nature of the system has made it possible to calculate the mass of the system directly, the mass fraction of Ceto in the system is 69.1 %. This also provided further evidence for the internal composition of both components. The density of the system was calculated to be 1.37 g / cm ³ to be relatively low. If the system inside is not porous (→ Rubble Piles ), it consists of a water-ice - rock mixture, the stone content is about 50%.
It has been hypothesized that tidal forces have (for example, collisions or 26Al - radiation ), the temperature may be increased along with other potential sources of heat sufficient to crystallize amorphous ice and fill the voids in the two bodies. The same tidal forces could be responsible for the quasi- circular orbits of the two components.
Moon
On 9 September 2006 discovered another team of astronomers at Keith S. Noll with the Hubble Space Telescope a natural companion, whose diameter is smaller by only 23.4%. Thus, this system in absolute and relative proportions strong parallels to Borasisi -Pabu system on, which is, however, a Cubewano double system; Moreover, these two components orbit in about 2.5 -fold greater distance. This system is regarded as a double asteroid system, comparable to the - officially as such - named System ( 79360 ) Sila Nunam.
Research
After his discovery, Ceto was in photos dating back to 1982 and calculate its orbit relatively precise. Since the asteroid and his companion were observed by different telescopes like the Hubble and the Spitzer Space Telescope and ground-based telescopes also, so far a total of exactly 80 times within 25 years. (As of Sept. 2012 )