1999AJ....117.2998G

We construct an empirical energy distribution for Arcturus from published scans, integrate it to obtain the total flux, and combine the latter with precise interferometric measurements of the limb-darkened angular diameter to derive the effective temperature. We conclude that the best value that can be derived within the framework of the associated assumptions is T_eff=4290±30 K. We then select a grid of model-atmosphere energy distributions by Kurucz and extract T_eff/log g/[Fe/H] by a least-squares fit to the adopted energy distribution. With the value of T_eff already constrained, we could investigate values for the surface gravity and metallicity of Arcturus; our results are logg=1.9, [Fe/H]=-0.68, and R=23 R_☉. However, we discuss evidence that relevant grids of models may not contain sufficient opacity.