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Ceres, asteroid and dwarf planet

 Automatic translation  Automatic translation Updated June 01, 2013

Ceres is the first bare asteroid. This spatial object 950 kilometers in diameter is situated in the main belt of asteroids between Mars and Jupiter. It is spherical, and enough massif to be raised to the rank of dwarfish planet in the same way as Pluto and Eris. The name of Ceres  is pulled by the Roman mythology, the goddess of the agriculture, the harvests and the fertility, associated with the Greek goddess Demeter.

NB: Ceres, girl of Saturn and Ops (either of Vesta or Cybele) taught to the men the art to cultivate the ground, to sow), to harvest the wheat, and to make it some bread, what made consider it as the goddess of the agriculture. Jupiter, her brother, been in love his beauty, had of her Proserpine (likened to Persephone of the Greek mythology). She was also liked by Neptune,
and, to escape her pursuit, she changed in mare.
The god noticed it and metamorphosed into horse. The courtship of Neptune made her a mother of the horse Arion.

Image: Ceres observed with the JWST telescope. Credit: NASA, ESA

 dwarf planet Ceres 
Ceres Characteristics
Aphelion 445 280 000 km
Perihelion 382 520 000 km
Semi-major axis 413 910 000 km
Equatorial diameter 974.6 km
Polar diameter 909.4 km
Axial tilt
Mass 9.445×1020 kg
Average orbital speed 17.882 km/s
Eccentricity 0.075797
Orbital period 4.6 yr or 1680.99 d
Synodic period 1.278 yr or 466.7 d
Inclination to Ecliptic 10.593°
Longitude of ascending node 80.3276°
Argument of perihelion  72.2921°
Right ascension 291°

Ceres or Hera


Ceres was a conscript Hera by the German astronomers. After its discovery, it had during almost 50 years the status of planet. With a mass of 9,445×1020 kg, Ceres concentrates to it only a third party of the total mass of the belt of asteroids - although it represents only approximately 3 % of the mass of the Moon. Ceres was observed for the first time on January 1st, 1801 by Giuseppe Piazzi, director of the observatory from Palermo to Sicily.
This one suggested baptizing it Ceres Ferdinandea by attaching the name of the goddess defender of Sicily to that of king of the island Ferdinand III de Sicily, his sponsor, then taken refuge in Palermo. Because of its position in the belt of asteroid main dynamics, its surface is probably heavily cratered.
If Ceres has big craters, they must be "relaxed", meaning that their shape became leveled in the time, with the gravity. Such relaxed craters are very common on the icy moons of Jupiter and Saturn.

Image: Giuseppe Piazzi, director of the observatory from Palermo to Sicily.




An occultation of a star by Ceres has been observed from Mexico and Florida in November 13, 1984.
In 2001, the Hubble Space Telescope has photographed Ceres and is made of a dark spot on the surface, which is probably a crater.
It was called "Piazzi".
The Keck telescope has also revealed two dark areas large. With Vesta, Ceres is one of the objectives of the probe Dawn embedded in the Delta 2 rocket, Thursday, September 27, 2007 at 11:34 UTC.
This ambitious NASA mission designed to orbit the Dawn spacecraft around Vesta in 2011 and Ceres in 2015. The study of these two celestial objects should allow a better understanding of the initial conditions of the Solar System shortly after its formation and to better understand the stages of planet formation.
Dawn who will travel a total of 5.1 billion kilometers, will evolve around 7 months of each asteroid. Overflights at low altitude are planned, at an altitude of 15 km for Vesta and Ceres 40 km.


Image: Orbit of Ceres, between Mars and Jupiter.

 Comparative size of dwarf planets

Image: Comparative size of dwarf planets.

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