Non-Lte Model Atmospheres. II. Effects of Balmer α

Four models of pure-hydrogen stellar atmospheres in radiative equilibrium with Teff = 15000 and log g = 4 are presented. Results are given for both the LTE and non-LTE cases, with and without the inclusion of Ha. The calculations show that (a) Ha causes a temperature rise, not a drop, at the surface, (b) the direct effect of cooling in the line is less important than the indirect effects of changing level popu- lations, and (c) the Balmer and Paschen jumps are unaltered by non-LTE effect