Notes. The visual phase Φ_Vis and period P was obtained from fitting a sine function to the AAVSO and AFOEV data of the last ten periods. For RW Vel such data are not available, and we list the GCVS (Samus et al. 2009) period instead. The UD diameters are obtained from a fit to all data (full λ), to the continuum bandpass 2.24–2.26 μm (2.25 μm), to the H₂O bandpass 1.95–2.05 μm (2.0 μm), and to the CO bandpass 2.35–2.45 μm (2.4 μm). The closure phases CP were averaged over the same bandpasses. The Rosseland mean angular diameter Θ_Ross is an average of the fitted diameters based on several closely fitting CODEX model atmospheres of any series with average effective temperature and an visual phase Φ_Model. was derived from Θ_Ross and m_bol (Table 2). d_PL is the period-luminosity distance from Whitelock et al. (2008). RW Vel is based on the same scale, but using the GCVS period and the mean K magnitude from Smith et al. (2002). The last two rows give the distances based on Θ_Ross and of the models at the respective phase, and based on m_bol and .