/R∗ 12.9 ± 0.3 a [au] 0.1212 ± 0.0033 T14 [hours] 5.5 ± 0.1 i [◦] 86.80 ± 0.32 Rp [R⊕] 12.3 ± 0.3 Mp [M⊕] 149 ± 15 ρp [kg/m3] 440 ± 60 Teq [K] 1095 ± 30
Notes: U indicates a uniform prior while N and L indicate normal and log-normal priors respectively.]

5.3. Interior structure modeling From the derived properties of TOI-2147 b and TOI-6019 b, we model their interior structure by comparing them to an extended grid of interior structure models from Thomas et al. (2025b) that was calculated with the GAS gianT modeL for Interiors (GASTLI Acuña et al. 2021, 2024). GASTLI was developed to model the interior structure of gas-giant and sub-Neptune exoplanets by assuming a core composed of water and rock with a fully convective envelope composed of H/He and metals on top. The interior is coupled self-consistently to a grid of atmospheric models. Thomas et al. (2025b) used GASTLI’s default atmospheric grid for warm exoplanets with equilibrium temperatures of Teq ≤1000 K. For both planets, we ran retrievals on the grid with Gaussian priors on the derived radius, mass, and ages. Following the procedure in Thomas et al. (2025b), we ran three retrievals for both planets, assuming different levels of envelope enrichment as we have no information on the atmospheric metallicity (log(Fe/H)) of our planets. The three different metallicity cases are: low (−2.0 < log(Fe/H) < 0.5), medium (0.5 < log(Fe/H) < 1.4), and high (1.4 < log(Fe/H) < 1.7). Interestingly, we found that for our high atmospheric metallicity retrieval (1.4 < log(Fe/H) < 1.7), the model was not able to match the observed radius with the observed mass. This indicates that, based on the observed mass and radius of the two planets, we would not expect any significant metal enrichment of their atmospheres, which is expected based on observations of the solar system giants and other gas giant exoplanets (Kipping 2014; Thorngren et al. 2016; Ohno et al. 2026; Thomas et al. 2025b). Table 4 shows our derived bulk metal mass fraction (Zp) and envelope mass fraction (fenv) for the other two retrievals, which were largely consistent with each other. Given the moderate eccentricities and low bulk densities, there is a possibility that the radii of our two planets are inflated, which can lead to an overestimation of the envelope mass fraction in interior modeling (Millholland et al. 2020; Hallatt & Millholland 2026). Tidal inflation is stronger for planets close to their host star, but could still play a role for eccentric WJs. We can use Eqs. 23 and 24 in Leconte et al. (2010) to estimate the amount of tidal heating that is expected from the derived eccentricity (see also Acuña-Aguirre et al. 2026). The reduced tidal quality factor of Q′ p = 3Qp/2k2 is ∼105 (Yoder & Peale 1981; Lainey et al. 2009) for Jupiter, ∼104 −105 for Uranus and Neptune (Tittemore & Wisdom 1990; Banfield & Murray 1992), and ∼103−104 for Saturn (Lainey et al. 2012; Polycarpe et al. 2018). Constraints on Q′ p for HJs have generally resulted in larger values Q′ p ≳105 (see e.g., Quinn et al. 2014; Kawai et al. 2025). As we had no information on Q′ p for our two planets, we took the range Q′ p = 103 −106 to estimate the minimum and maximum expected temperature from tidal heating. For TOI-2147 b this results in a tidal temperature of Ttide = 40 −230 K and for TOI-6019 b, we estimated Ttide = 140 −800 K. With this, we run another set of interior retrievals where we put a prior on the internal temperature from the tidal heating. The total internal temperature is calculated as Tint = (T 4 tide + T 4 age)1/4 with Tage