Exoplanets Found to Be Richer in Water Than Expected

A recent study led by Caroline Dorn, Professor for Exoplanets at ETH Zurich, reveals that planets may be more complex and water-rich than previously thought. The research, conducted in collaboration with Haiyang Luo and Jie Deng from Princeton University, utilized model calculations based on fundamental laws of physics to investigate the distribution of water within planets. The findings suggest that large planets with high-pressure interiors could harbor significant amounts of water, not just on their surfaces but also deep within their iron cores and silicate mantles. This discovery has implications for the interpretation of astronomical data, particularly for exoplanets.

The study was inspired by investigations into Earth's water content, which showed that the oceans on the surface represent only a small fraction of the planet's total water. Simulations indicated that the Earth's interior might hold more than 80 times the water found in its oceans. The research also found that under high-pressure conditions, iron can absorb up to 70 times more water than silicates, with the water existing in the form of hydrogen and oxygen rather than H2O molecules due to the extreme pressure at the core. This could significantly affect our understanding of the composition and habitability of exoplanets, especially those observed by instruments like the James Webb Space Telescope, which is currently analyzing exoplanet atmospheres.