Mass–radius diagram for HIP 41378 transiting planets. Confirmed planets from the NASA Exoplanet Archive with 20% precision on mass and radius are represented as grey dots. Planets with densities under 0.2 g/cm⁻³ are highlighted. The colours show the importance of mass loss through α_evap. Theoretical composition models for rocky planets and water worlds from Zeng et al. (2019) are represented as dashed lines, and rocky planets with H/He atmospheres from Lopez & Fortney (2014) are represented as dotted lines. The isodensity curves are show straight lines. Parts of this plot were prepared using mr-plotter (Castro-González et al. 2023).