Mars: A new core-crystallization regime

The evolution of the martian core is widely assumed to mirror the characteristics observed for Earth's core. Data from experiments performed on iron-sulfur and iron-nickel-sulfur systems at pressures corresponding to the center of Mars indicate that its core is presently completely liquid and that it will not form an outwardly crystallizing iron-rich inner core, as does Earth. Instead, planetary cooling will lead to core crystallization following either a snowing-core model, whereby iron-rich solids nucleate in the outer portions of the core and sink toward the center, or a sulfide inner-core model, where an iron-sulfide phase crystallizes to form a solid inner core.