Mass and radius diagram for Ross 176 b. There are two world composition models from Zeng et al. 2019: The brown model is an Earth-like planet (30% Fe + 70% MgSiO₃), the blue model is a waterworld planet (50% H₂O + 50% Earth-like), the navy blue line is a full water-world planet (100% H₂O) with a T_eq of 700 K. The gray dots show confirmed exoplanets from the NASA exoplanet archive filtered with a mass and radius precision better than 20% that orbit K-type stars in April 2025.