“Ceres”的概念、定义、翻译、参考文献-科学参考

Ceres

Astronomy

The first asteroid to be discovered, by G. Piazzi on 1801 January 1, and hence given the number 1. Since 2006 it has also been classified as a dwarf planet. Ceres is by far the largest member of the asteroid belt, an oblate spheroid 965 × 891 km, mean diameter 940 km, mass 9.4 × 10²⁰ kg (about 1% the mass of the Moon) and mean density 2.1 g/cm³. Its rotation period is 9.074 hours. Ceres contains roughly one-third the mass of the entire asteroid belt. Its mean magnitude at opposition is 7.4; only Vesta can ever become brighter. Its orbit has a semimajor axis of 2.77 au, period 4.61 years, perihelion 2.56 au, aphelion 2.98 au, and inclination 10°.6. Ceres is of G type, with a reflectance spectrum that indicates a surface composition resembling the carbonaceous chondrite meteorites. However, its low density implies that beneath the surface it has a considerable layer of water ice surrounding a rocky core. Ceres is the largest member of a small family of asteroids with a mean distance of 2.76–2.80 au from the Sun and orbital inclinations of 9–11°. Other Ceres family members include (39) Laetitia, (264) Libussa, (374) Burgundia (all S-type), and (446) Aeternitas (A-type). NASA’s Dawn spacecraft went into orbit around it in 2015 March, revealing a surface saturated with impact craters, the largest of which is Kerwan, 280 km across, and detecting water ice inside some of the permanently shadowed craters near the poles.

Space Exploration

The largest object in the asteroid belt and the only dwarf planet located in the inner Solar System. The object, 940 km in diameter, was discovered by Italian astronomer Giuseppe Piazzi in 1801. The first object in the asteroid belt to be discovered, Ceres was known as an asteroid until scientists reclassified it in 2006. Ceres orbits the Sun every 4.6 years at an average distance of 414 million km. Its mass is about 0.014 of that of the Earth's Moon. In 2007, the spacecraft Dawn took off on a mission to study Vesta and Ceres. It arrived at Ceres in March 2015 and took close-up images of a pair of bright spots on the planet. At first believed to be composed of hydrated magnesium sulphate (like Epsom salt), the spots likely formed from impacts heating subsurface ice and releasing briny liquid water or vapour in geysers that deposit salty frozen droplets onto the surface. Once the water sublimates away, it leaves behind a shiny, salt-rich residue that we see as bright spots on crater floors. Eventually Dawn imaged 130 bright patches on the dwarf planet's dark surface, mostly associated with craters.

Geology and Earth Sciences

A solar system dwarf planet, diameter 974 km, approximate mass 10²¹ kg; rotation period 9.078 hours; orbital period 4.6 years. Ceres was discovered in 1801 by G. Piazzi. In 2007, the spacecraft Dawn took off on a mission to study Vesta and Ceres. It arrived at Ceres in March 2015 to map the surface in detail and take close-up images of a pair of bright spots on the planet believed to be deposits of water ice or mineral salts. In 2018 it was still in orbit about Ceres, propelled by an ion engine.
https://dawn.jpl.nasa.gov/mission/ Dawn Mission Overview.

单词	Ceres
释义	Ceres Astronomy The first asteroid to be discovered, by G. Piazzi on 1801 January 1, and hence given the number 1. Since 2006 it has also been classified as a dwarf planet. Ceres is by far the largest member of the asteroid belt, an oblate spheroid 965 × 891 km, mean diameter 940 km, mass 9.4 × 10²⁰ kg (about 1% the mass of the Moon) and mean density 2.1 g/cm³. Its rotation period is 9.074 hours. Ceres contains roughly one-third the mass of the entire asteroid belt. Its mean magnitude at opposition is 7.4; only Vesta can ever become brighter. Its orbit has a semimajor axis of 2.77 au, period 4.61 years, perihelion 2.56 au, aphelion 2.98 au, and inclination 10°.6. Ceres is of G type, with a reflectance spectrum that indicates a surface composition resembling the carbonaceous chondrite meteorites. However, its low density implies that beneath the surface it has a considerable layer of water ice surrounding a rocky core. Ceres is the largest member of a small family of asteroids with a mean distance of 2.76–2.80 au from the Sun and orbital inclinations of 9–11°. Other Ceres family members include (39) Laetitia, (264) Libussa, (374) Burgundia (all S-type), and (446) Aeternitas (A-type). NASA’s Dawn spacecraft went into orbit around it in 2015 March, revealing a surface saturated with impact craters, the largest of which is Kerwan, 280 km across, and detecting water ice inside some of the permanently shadowed craters near the poles. Space Exploration The largest object in the asteroid belt and the only dwarf planet located in the inner Solar System. The object, 940 km in diameter, was discovered by Italian astronomer Giuseppe Piazzi in 1801. The first object in the asteroid belt to be discovered, Ceres was known as an asteroid until scientists reclassified it in 2006. Ceres orbits the Sun every 4.6 years at an average distance of 414 million km. Its mass is about 0.014 of that of the Earth's Moon. In 2007, the spacecraft Dawn took off on a mission to study Vesta and Ceres. It arrived at Ceres in March 2015 and took close-up images of a pair of bright spots on the planet. At first believed to be composed of hydrated magnesium sulphate (like Epsom salt), the spots likely formed from impacts heating subsurface ice and releasing briny liquid water or vapour in geysers that deposit salty frozen droplets onto the surface. Once the water sublimates away, it leaves behind a shiny, salt-rich residue that we see as bright spots on crater floors. Eventually Dawn imaged 130 bright patches on the dwarf planet's dark surface, mostly associated with craters. Geology and Earth Sciences A solar system dwarf planet, diameter 974 km, approximate mass 10²¹ kg; rotation period 9.078 hours; orbital period 4.6 years. Ceres was discovered in 1801 by G. Piazzi. In 2007, the spacecraft Dawn took off on a mission to study Vesta and Ceres. It arrived at Ceres in March 2015 to map the surface in detail and take close-up images of a pair of bright spots on the planet believed to be deposits of water ice or mineral salts. In 2018 it was still in orbit about Ceres, propelled by an ion engine. https://dawn.jpl.nasa.gov/mission/ Dawn Mission Overview.
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