Metallicity of mono- and multiperiodic beta Cephei stars

Analyzing IUE ultraviolet spectra of β 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 β 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.