Abstract:
Various theoretical constraints are imposed on simultaneous light, color, and line profile observations to identify the surface indices of two nonradial modes present in the line profile variable B star 53 Persei during late 1977 and 1978. Excellent quantitative agreement between linear nonradial theory and the observations is reached for the modes 1 = 3, m = -2 and -3, but for no other modes. This unambiguous mode identification is made possible because of the fortunate circumstance that the light variations in this long-period pulsator are evidently due to geometric and not temperature effects.