Potential mass (upper panel) and radius (lower panel) evolutionary tracks for V1298 Tau c (black) and V1298 Tau b (red). M₀ and R₀ refer to the current mass and radius, respectively. For planet c, we assume 5.24 R⊕ and 17 M⊕ (median value from ATMO atmospheric retrieval) as the current radius and mass. For planet b, we assume 9.95 R⊕ as the current radius. We show models for two values for the current mass for planet b: 10 M_⊕ (solid red line), which is consistent within 1σ with the mass measured from our ATMO retrievals (8-4 M æ), and 23 Mæ which is the 3σ upper limit from Barat et al. (2024). The left panels zoom in on the first 100 Myr and the right panels show the evolutionary tracks for 1 Gyr. The evolutionary models described in Appendix D calculate the mass and radius evolution due to cooling and atmospheric mass loss. We used evolutionary models described in Vazan et al. (2022). For further discussion, see Sect. 4.4. These evolutionary models represent one possible scenario for the early evolution of both these planets and do not take into account the planet mass uncertainty.