Ceres (dwarf planet) facts for kids
|Discovered by||Giuseppe Piazzi|
|Discovery date||January 1, 1801|
|MPC designation||1 Ceres|
|A899 OF; 1943 XB|
|Epoch November 26, 2005
2.765 956 424 AU
Average orbital speed
|Flattening||0.067 ± 0.005|
|Mass||9.46 ± 0.04×1020 kg|
Equatorial surface gravity
Equatorial escape velocity
Sidereal rotation period
|6.7 to 9.32|
|0.84" to 0.33"|
Ceres was discovered on 1 January 1801, by Giuseppe Piazzi, and is named after the Roman goddess Ceres, as the goddess of growing plants, the harvest, and of motherly love. After about 200 years from its discovery, the International Astronomical Union decided to upgrade Ceres from an asteroid (or minor planet) to dwarf planetary status in 2006.
With a diameter of about 950 km, Ceres is by far the largest and most massive object in the asteroid belt, and has about a third of the belt's total mass. It was once thought to be smaller than Vesta, which is brighter.
Ceres's small size means that even at its brightest, it is too dim to be seen by the naked eye, except under extremely dark skies. As a result, its surface features are barely visible even with the most powerful telescopes, and little was known about it until the robotic NASA spacecraft Dawn approached Ceres for its orbital mission in 2015.
Dawn found Ceres's surface to be a mixture of water ice and hydrated minerals such as carbonates and clay. Gravity data suggest Ceres to be partially differentiated into a muddy (ice-rock) mantle/core and a less dense but stronger crust that is at most thirty percent ice by volume. Although Ceres likely lacks an internal ocean of liquid water, brines still flow through the outer mantle and reach the surface, allowing cryovolcanoes such as Ahuna Mons to form roughly every fifty million years.
Ceres has an unusual crater, Occator which contains bright salts.
Ceres follows an orbit between Mars and Jupiter, near the middle of the asteroid belt, with an orbital period (year) of 4.6 Earth years. Compared to other planets and dwarf planets, Ceres's orbit is moderately tilted relative to that of Earth.
Ceres is the largest asteroid in the main asteroid belt. Measurements from the Dawn spacecraft found a mean diameter of 939.4 km (583.7 mi) and a mass of 9.38×1020 kg. This gives Ceres a density of 2.16 g/cm3, suggesting that a quarter of its mass is water ice.
Dawn revealed that Ceres has a heavily cratered surface, though with fewer large craters than expected.
Ceres's north polar region shows far more cratering than the equatorial region.
In 2017, Dawn confirmed that Ceres has a transient atmosphere of water vapour.
Origin and evolution
Ceres is a surviving protoplanet that formed 4.56 billion years ago; alongside Pallas and Vesta, one of only three remaining in the inner Solar System, with the rest either merging to form terrestrial planets, being shattered in collisions or being ejected by Jupiter.
Although Ceres is not as actively discussed as a potential home for microbial extraterrestrial life as Mars, Europa, Enceladus, or Titan are, it has the most water of any body in the inner Solar System after Earth, and the likely brine pockets under its surface could provide habitats for life.
|The Solar System|
☾ = moon(s) ∅ = rings
|Mercury||Venus||Earth ☾||Mars ☾|
|Jupiter ☾ ∅||Saturn ☾ ∅||Uranus ☾ ∅||Neptune ☾ ∅|
|Dwarf planets||Ceres||Pluto ☾||Haumea ☾||Makemake|
|Groups and families: Vulcanoids · Near-Earth asteroids · Asteroid belt
Jupiter Trojans · Centaurs · Neptune Trojans · Asteroid moons · Meteoroids · Pallas · Juno · Vesta · Hygiea · Interamnia · Europa
|See also the list of asteroids.|
|Kuiper belt – Plutinos: Orcus · Ixion – Cubewanos: Varuna ·
Quaoar · Huya
|Scattered disc: Sedna|
|Comets||Periodic comets and non-periodic comets
Damocloids · Oort cloud
|See also the list of solar system objects|
Images for kids
Giuseppe Piazzi, discoverer of Ceres
Orbits of Ceres (red, inclined) along with Jupiter and the inner planets (white and gray). The upper diagram shows Ceres's orbit from top down. The bottom diagram is a side view showing Ceres's orbital inclination to the ecliptic. Lighter shades indicate above the ecliptic; darker indicate below.
Artist's conception of Dawn spacecraft
In Spanish: Ceres (planeta enano) para niños
Ceres (dwarf planet) Facts for Kids. Kiddle Encyclopedia.