Best-fitting hydrostatic model (blue dashed line) on the spectrophotometric measurements. Photometric measurements (squares: Bagnulo et al. 1998 + triangles: Whitelock et al. 2006; see Table 4) and ISO/SWS spectra of R Scl at different epochs (dotted lines) are shown. A blackbody continuum having the same temperature (T_eff = 2700 K) and angular diameter (⊘ _⋆ = 10.2 mas) as the synthetic COMARCS spectrum is superimposed (black solid line).