Stability of H <sub>3</sub> O at extreme conditions and implications for the magnetic fields of Uranus and Neptune
Peihao Huang, Hanyu Liu, Jian Lv, Quan Li, Chunhong Long, Yanchao Wang, Changfeng Chen, Russell J. Hemley, Yanming Ma
Abstract
Significance Understanding the interior structure and dynamics of outer Solar System planets in terms of their component materials is a major scientific challenge. A highly intriguing case concerns the anomalous nondipolar and nonaxisymmetric magnetic fields of Uranus and Neptune. A thin-shell dynamo model has been shown to capture observed phenomena but leaves unexplained its origin and materials basis. We report extensive theoretical calculations that indicate the stability of trihydrogen oxide (H 3 O) in solid, superionic, and fluid metallic states at the deep interior conditions of these planets. The fluid metallic phase is stable in a thin-shell zone near their cores and exhibits the properties required to produce the observed enigmatic magnetic fields. These findings have implications for other planets, including related exoplanets.