Relationship between selected system properties for hot giant Jupiters (WASP-43b, HD 189733b, HD 209458b) and ultra-hot Jupiters (HAT-P-7b, WASP-18b, WASP-103b, WASP-121b). The two classes of giant gas planets are clearly separated with respect to their global planetary temperature, T_eq (K) and the planets’ surface gravity, g (g_Jup). There is not as clear a separation between the hot giant gas planets and ultra-hot Jupiters regarding their host star’s effective temperature, T_eff (K), bulk planetary density ρ_p, and stellar metallicity [Fe/H]. The ultra-hot Jupiters are shown by circle markers, the giant-gas planets by the square markers and a sub-Neptune (HD 86226c) by the diamond marker. We also include the sample of hot and the ultra-hot Jupiters from Table 1 in Baxter et al. (2020) in the T_eff versus T_eq plot (top right) as smaller light grey points.