Dwarf planets · Space Codex
Ceres
The first asteroid ever found is also a dwarf planet holding a quarter of the main belt's mass.
Dwarf planet · largest body in the asteroid belt
At a glance
Key points
Bright salt deposits in Occator crater mark brine that rose from deep below.
- First asteroid discovered (1801) and the only dwarf planet in the inner Solar System
- Salt 'bright spots' in Occator crater
- A day lasts only about 9 hours
Surface
Ceres is a dark, cratered globe, but Occator crater holds dazzling white spots of sodium carbonate, the most carbonate-rich deposits seen beyond Earth. Dawn's gravity data point to a briny reservoir tens of kilometres below that fed them; some salts appear only centuries old. Ahuna Mons, a lone dome about 4 km high, is the youngest of about two dozen possible ice volcanoes.
Interior
Ceres is partly differentiated: a rocky interior under a crust of rock, ice and salts. It may have hosted a global ocean early on, and pockets of brine may remain.
Exploration
NASA's Dawn reached Ceres in March 2015, making it the first dwarf planet visited by a spacecraft, and orbited until its fuel ran out in 2018.
What we still don't know
How much liquid remains inside today, and whether Ceres formed where it is or migrated in from the outer Solar System.
Missions
- 2007–2018
Dawn
NASACompletedOrbited Vesta (2011–2012) then Ceres (2015–2018) with ion propulsion.
Related entries
- Main asteroid beltRocky debris between Mars and Jupiter
- 4 VestaA layered protoplanet
Sources
- UC Berkeley: Ceres has reservoirs of salty water (2020) (opens in a new tab)
- JPL Small-Body Database: 1 Ceres (opens in a new tab)
- NASA Science: Ceres facts (opens in a new tab)
- NASA JPL: PIA22769: Ahuna Mons (opens in a new tab)
Last reviewed against these sources. Built from public NASA, ESA and JPL data; not affiliated with or endorsed by any agency.