Experimental evidence for a phase transition in magnesium oxide at exoplanet pressures

Abstract

Little is known about the structure of possible mantle materials of extra-solar super-Earths with interior pressures of up to 1,000 GPa. Dynamic X-ray diffraction measurements of ramp-compressed magnesium oxide, an important component of Earth’s mantle, show a solid–solid state transition at about 600 GPa, with a high-pressure structure that is stable up to 900 GPa.