  We have modeled the 2.6 - 3.7 um spectrum of the red semiregular variable R
Doradus observed with the Short-Wavelength Spectrometer on board the Infrared
Space Observatory. The wavelength resolution of the observations varies between
R = 2000 - 2500. We have calculated a synthetic spectrum using a hydrostatic
model photosphere in spherical geometry. The agreement between the synthetic
spectrum and the ISO observations is encouraging, especially in the wavelength
region of 2.8 - 3.7 um, suggesting that a hydrostatic model photosphere is
adequate for the calculation of synthetic spectra in the near infrared for this
moderately varying red giant star. However, an additional absorption component
is needed at 2.6- 2.8 um and this discrepancy is discussed. The spectral
signatures are dominated by water vapour in the stellar photosphere, but
several photospheric OH, CO, and SiO features are also present. The effective
temperature and surface gravity derived for R Dor, based on the 2.6 - 3.7 um
ISO spectrum and the modeling of it with a hydrostatic model photosphere, are
3000 +- 100 K and log g = 0 +- 1 (cgs), respectively. The spectral region
observed is found to be temperature sensitive. The effective temperature given
here is slightly higher than those reported in the literature. We also discuss
possible reasons for this.
