Comparison of predicted and observed spectral energy distributions of A-type stars

Emergent fluxes are determined from published low-resolution spectrum scans from 1100 to 8000 A for seven bright A-type stars which have well-determined empirical angular diameters, effective temperatures, and parallaxes. The stellar flux is compared with the emergent flux from a line-blanketed model atmosphere which has the same effective temperature. The observational accuracy is found to be sufficient to place useful constraints on model-atmosphere results. In the UV region, where observational uncertainties in the flux are + or - 10%-20%, the agreement is generally acceptable; in the ground-based region, where the observed fluxes should be about 10 times more accurate, significant discrepancies exist in absolute fluxes and colors. Computed line wings of H-gamma for Alpha CMa and Alpha Lyr are too bright near line center. These results are briefly discussed in terms of the model-atmosphere structure.