A 5-kilometer-high mountain on the dwarf planet Ceres is most likely volcanic in origin, according to the findings of NASA’s Dawn mission. The lonely mountain, named Ahuna Mons, was actually a cryovolcano that spewed a liquid composed of volatiles like water instead of silicates.

Ahuna Mons is unlike anything scientists have seen elsewhere in the solar system. According to Ottaviano Ruesch of NASA’s Goddard Space Flight Center in Greenbelt, Maryland, the ice volcano “is the only known example of a cryovolcano that potentially formed from a salty mud mix, and that formed in the geologically recent past.”

This ice volcano discovery is just one of the many that the Dawn spacecraft found while orbiting Ceres. The study published in the journal Science also shows that Ceres has a temporary atmosphere.

The gamma ray and neutron (GRaND) detector aboard the spacecraft reveal that Ceres had accelerated electrons from the solar wind to very high energies in just six days. Scientists believe that this is the result of the interaction between the solar wind’s energetic particles and atmospheric molecules.

The temporary atmosphere would be consistent with the Herschel Space Observatory’s finding that the dwarf planet has water vapor. However, the research team still needs to follow up on this.

Moreover, Dawn’s visible and infrared mapping spectrometer (VIR) detected water ice at Oxo Crater, a tiny sloped depression located at mid-latitudes on Ceres. The dwarf planet’s crust has a significant amount of water-ice, the scientists believe.

Ceres also contains craters with flow-like features. The shapes of some craters also suggest that water-ice is present in them. Ceres has experienced a complex geological evolution, which is why the distribution of craters is uneven and its crust is not uniform.

A study also found that clay-forming minerals called phyllosilicates are found all over Ceres. These minerals are rich in magnesium and have some amount of ammonium embedded. The dwarf planet must have undergone a global process involving water that caused the minerals’ distribution on its surface.

The Dawn spacecraft is presently 385 kilometers above Ceres’ surface. On Sept. 2, it will increase its altitude to gather more information that can solve the mysteries the dwarf planet holds.