Advances in astronomical observations have resulted in the discovery of an extraordinary number of extrasolar planets, some of which are believed to have a rocky composition similar to Earth. Learning more about their interior structure could provide important clues about their potential habitability.

Led by Lawrence Livermore National Laboratory (LLNL), a team of researchers aims to unlock some of these secrets by understanding the properties of iron oxide —one of the constituents of Earth’s mantle—at the extreme pressures and temperatures that are likely found in the interiors of these large rocky extrasolar planets. The results of their experiments were published today in Nature Geoscience.

“Because of the limited amount of data available, the majority of interior structure models for rocky exoplanets assume a scaled-up version of the Earth, consisting of an iron core, surrounded by a mantle dominated by silicates and oxides. However, this approach largely neglects the different properties the constituent materials may have at pressures exceeding those existing inside the Earth,” said Federica Coppari, LLNL physicist and lead author on the study. “With the ever-increasing number of confirmed exoplanets, including those believed to be rocky in nature, it is critical to gain a better understanding of how their planetary building blocks behave deep inside such bodies.”