Planet radius vs. Roche filling factor for the sample of planets with published detections of atmospheric escape using He^*, Hα, or other lines (represented as circles), with colors indicating the host star spectral type. We label the three early-type planetary systems with extended tails of escaping atmospheric gas: HAT-P-32 b (S. Czesla et al. 2022; Z. Zhang et al. 2023), HAT-P-67 b (M. Gully-Santiago et al. 2023), and WASP-121 b (R. Allart et al. 2025). We also label the target of this study: WASP-12 b. For a full list of planets with outflow detections, see J. Orell-Miquel et al. (2024); we also include detections for HAT-P-26 b (S. Vissapragada et al. 2022), TOI-1259 A b (M. Saidel et al. 2025a), TOI-1420 b (S. Vissapragada et al. 2024), WASP-33 b (F. Yan et al. 2021), WASP-94 A b (S. Mukherjee et al. 2025), WASP-121 b (S. Czesla et al. 2024b; R. Allart et al. 2025), and WASP-180 A b (M. Saidel et al. 2026).