page_title: Geology of Ceres
section_title: Montes
hierarchical_section_title: Geology of Ceres / Montes
caption_attribution_description: English: Ceres in true color taken by Dawn on May 4, 2015. Oxo Crater, Haulani Crater, and Ahuna Mons are visible.
context_page_description: The geology of Ceres consists of the characteristics of the surface, the crust and the interior of the dwarf planet Ceres. The surface of Ceres is comparable to the surfaces of Saturn's moon Rhea and Tethys, and Uranus's moon Umbriel and Oberon.
  The spectrum of Ceres is similar to that of C-type asteroids. However, since it also has spectral features of carbonates and clay minerals, which are usually absent in the spectra of other C-type asteroids, Ceres is sometimes classified as a G-type asteroid.
  Ceres's surface has an albedo of 0.09, which is quite dark compared to the moons in the outer Solar System. This might be a result of the relatively high temperature of Ceres's surface, the maximum temperature with the Sun overhead was estimated from measurements to be 235 K on 5 May 1991. In a vacuum, ice is unstable at this temperature. Material left behind by the sublimation of surface ice could explain the dark surface of Ceres compared to the icy moons of the outer Solar System.
context_section_description: The best known mons on Ceres is Ahuna Mons, a cryovolcano about 6 kilometers high and 15 kilometers wide at the base. It was discovered on images taken by the Dawn spacecraft in orbit around Ceres in 2015. 
  Bright streaks run top to bottom on its slopes; these streaks are thought to be salt, similar to the better known Cererian bright spots. The low crater count on Ahuna mons suggests that the cryovolcano could be no older than 200 million years, and indeed models of plastic relaxation of ice at the latitude of Ahuna Mons is consistent with that age.
  There are twenty-two identified montes on Ceres. Most of these have relaxed substantially over time, and it was only after modeling of the expected shapes of old cryovolcanoes that they were identified. It has been calculated that Ceres averages one such cryovolcano every 50 million years. Yamor Mons (previously named Ysolo Mons), near the north pole, has a diameter of 16 km and is the only other Cererian with the shape of Ahuna Mons,, though old and battered, the cold temperatures at the pole have preserved its shape.Liberalia Mons is near the equator and has a diameter of 90 km.
caption: True-color image of Ceres
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