Journal of Geophysical Research - Solid Earth ; Icarus

A new hydrous phase, ε-AlOOH, was observed to be stable at pressures above ~200 GPa. The stability of ε-AlOOH at extremely high pressures may affect the modelling results of the internal structure and deep water circulation of some extra-solar planets, such as terrestrial super-Earths, because the hydroxide may store water in these regions.