Orbit::Ceres (dwarf planet)


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Proper (long-term mean) orbital elements compared to osculating (instant) orbital elements for Ceres:
(in AU)
e i Period
(in days)
Proper<ref name="Ceres-POE" /> 2.7671 0.116198 9.647435 1681.60
Osculating<ref name="jpl_sbdb" />
(Epoch 23 July 2010 )
2.7653 0.079138 10.586821 1679.66
Difference 0.0018 0.03706 0.939386 1.94
Orbit of Ceres

Ceres follows an orbit between Mars and Jupiter, within the asteroid belt, with a period of 4.6 Earth years.<ref name="jpl_sbdb" /> The orbit is moderately inclined (i = 10.6° compared to 7° for Mercury and 17° for Pluto) and moderately eccentric (e = 0.08 compared to 0.09 for Mars).<ref name="jpl_sbdb" />

The diagram illustrates the orbits of Ceres (blue) and several planets (white and gray). The segments of orbits below the ecliptic are plotted in darker colors, and the orange plus sign is the Sun's location. The top left diagram is a polar view that shows the location of Ceres in the gap between Mars and Jupiter. The top right is a close-up demonstrating the locations of the perihelia (q) and aphelia (Q) of Ceres and Mars. In this diagram (but not in general), the perihelion of Mars is on the opposite side of the Sun from those of Ceres and several of the large main-belt asteroids, including 2 Pallas and 10 Hygiea. The bottom diagram is a side view showing the inclination of the orbit of Ceres compared to the orbits of Mars and Jupiter.

Ceres was once thought to be a member of an asteroid family.<ref name="Cellino">{{#invoke:citation/CS1|citation |CitationClass=book }}</ref> The asteroids of this family share similar proper orbital elements, which may indicate a common origin through an asteroid collision some time in the past. Ceres was later found to have spectral properties different from other members of the family, which is now called the Gefion family after the next-lowest-numbered family member, 1272 Gefion.<ref name="Cellino" /> Ceres appears to be merely an interloper in the Gefion family, coincidentally having similar orbital elements but not a common origin.<ref name="Kelley">{{#invoke:Citation/CS1|citation |CitationClass=journal }}</ref>

The rotational period of Ceres (the Cererian day) is 9 hours and 4 minutes.<ref name="NSSDC">{{#invoke:Citation/CS1|citation |CitationClass=journal }}</ref>

Ceres is in a near-1:1 mean-motion orbital resonance with Pallas (their proper orbital periods differ by 0.2%).<ref name="Kovačević">{{#invoke:Citation/CS1|citation |CitationClass=journal }}</ref> However, a true resonance between the two would be unlikely; due to their small masses relative to their large separations, such relationships among asteroids are very rare.<ref name="Christou">{{#invoke:Citation/CS1|citation |CitationClass=journal }}</ref> Nevertheless, Ceres is able to capture other asteroids into temporary 1:1 resonant orbital relationships (for periods up to 2 million years or more); fifty such objects have been identified.<ref name="Christou2012">{{#invoke:Citation/CS1|citation |CitationClass=journal }}</ref>


Several temporary trojans of Ceres are known.<ref name=CeresVestatrojans>A population of main belt asteroids co-orbiting with Ceres and Vesta</ref>

Transits of planets from Ceres

Mercury, Venus, Earth, and Mars can all appear to cross the Sun, or transit it, from a vantage point on Ceres. The most common transits are those of Mercury, which usually happen every few years, most recently in 2006 and 2010. The most recent transit of Venus was in 1953, and the next will be in 2051; the corresponding dates are 1814 and 2081 for transits of Earth, and 767 and 2684 for transits of Mars.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

Ceres (dwarf planet) sections
Intro  History  Physical characteristics  Orbit  Origin and evolution  Potential habitability  Observation  Exploration  Maps  Gallery  See also  Notes  References  External links  

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