Ceres (dwarf planet)

Ceres (/ˈsɪərz/;[18] minor-planet designation: 1 Ceres) is a dwarf planet in the asteroid belt between the orbits of Mars and Jupiter. It was the first asteroid discovered, on 1 January 1801, by Giuseppe Piazzi at Palermo Astronomical Observatory in Sicily and announced as a new planet. Ceres was later classified as an asteroid and then a dwarf planet  the only one orbiting entirely within Neptune's orbit.

1 Ceres ⚳
Ceres in true colour in 2015
Discovered byGiuseppe Piazzi
Discovery date1 January 1801
1 Ceres
Named after
AdjectivesCererian, -ean (/sɪˈrɪəriən/)
Orbital characteristics[2]
Epoch 21 January 2022 (JD 2459600.5 )
Aphelion2.98 AU (446 million km)
Perihelion2.55 AU (381 million km)
2.77 AU (414 million km)
  • 4.60 yr
  • 1680 d
17.9 km/s
7 December 2022
Proper orbital elements[5]
2.77 AU
78.2 deg / yr
4.60358 yr
(1681.458 d)
Precession of perihelion
54.1 arcsec / yr
Precession of the ascending node
−59.2 arcsec / yr
Physical characteristics
Dimensions(964.4 × 964.2 × 891.8) ± 0.2 km[2]
Mean diameter
939.4±0.2 km[2]
2,772,368 km2[6]
Volume434,000,000 km3[6]
Mean density
2.162±0.008 g/cm3[2]
Equatorial surface gravity
0.36±0.15[7][lower-alpha 1] (estimate)
Equatorial escape velocity
0.51 km/s[6] 1141 mph
9.074170±0.000001 h[2]
Equatorial rotation velocity
92.61 m/s[6]
North pole right ascension
North pole declination
0.090±0.0033 (V-band)[12]
Surface temp. min mean max
Kelvin ≈110[13] 235±4[14]
0.854″ to 0.339″

    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. Its apparent magnitude ranges from 6.7 to 9.3, peaking at opposition (when it is closest to Earth) once every 15- to 16-month synodic period. 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 30% 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. This makes Ceres the closest known cryovolcanic body to the Sun, and the brines provide a potential habitat for microbial life.

    In January 2014, emissions of water vapour were detected around Ceres, creating a tenuous, transient atmosphere known as an exosphere.[19] This was unexpected because vapour is usually a hallmark of comets, not asteroids.

    Share this article:

    This article uses material from the Wikipedia article Ceres (dwarf planet), and is written by contributors. Text is available under a CC BY-SA 4.0 International License; additional terms may apply. Images, videos and audio are available under their respective licenses.