A Comparative Study of the Balmer Decrements in Emissionline Stars

The Balmer decrements of the emission-line stars exhibit a large variety from very steep to very slow, or even inverted decrements. This variety can be understood in terms of the “excitation level” , which expresses the quality of the energy source required to ionize and excite the hydrogen atoms. At present, however, observational material is insufficient for most types of emission line stars. Further observations are desired.