Notes. (1) Photospheric temperature for comparison with the MARCS model atmosphere adopted by Davies & Plez (2021). The chromospheric temperature and density refer to the local temperature maximum at 1.4–1.5 R_⋆ (model A, values in brackets are for model variant B). (2) See Appendix G for the determination of R_⋆, L_⋆, and d. θ_K is the angular K-band size (Lacour 2010). The sightline velocity is obtained from spectral profile matching of the [OI]_λ63 line (cf. υ_LSR = 32.7km s⁻¹, Montargès et al. 2021). (3) Mass of Helium burning core, inferred from the core mass – luminosity relation (SNAPSHOT models, Farrell et al. 2020b). (4) Present and main-sequence stellar mass from matching evolutionary track models (Ekström et al. 2012, non-rotating variant). Cf. M_*^(total) = 10 M_⊙ from luminosity-surface gravity relation (Messineo et al. 2021). (5) Distance from star where atomic hydrogen fraction becomes negligible. (6) Enclosed circumstellar total and HI gas mass. Values in brackets refer to model B (cf. M_HI = 0.018 M_⊙ from Gérard et al. 2025, but scaled to our 421 pc distance). (7) The mass loss rate is not constant; this value refers to the outer model boundary and includes the cool gas dilution. See text for details. (8) Circumstellar-envelope and interstellar contributions (Shenoy et al. 2016, matching their τ_{λ37,1 µm}, and Levesque et al. 2005, respectively).