Water-rich sub-Neptunes and rocky super Earths around different Stars: Radii shaped by Volatile Partitioning, Formation, and Evolution
The study tested how water is distributed inside sub-Neptunes during formation and evolution by modeling four scenarios: perfect mixing, fractionation, layering, and water dissolution into a magma ocean. Findings show that while mixed models work for smaller planets, the water dissolution model better explains larger planets above $3 M_{\oplus}$. Layered structures consistently fail to match observed mass-radius relations.