Metallicity of mono- and multiperiodic beta Cephei stars

Analyzing IUE ultraviolet spectra of beta Cep pulsating stars we have noticed that multiperiodic variables have a larger mean metal abundance in the photosphere, [m/H], than monoperiodic ones. We apply statistical tests to verify this dichotomy. We obtain that, with a large probability, the multiperiodic beta Cep stars have greater values of [m/H]. This result is consistent with the linear non-adiabatic theory of pulsation of early B-type stars.