We report the discovery of the hottest hybrid B-type pulsator, KIC 3240411, that exhibits the period spacing in the low-frequency range. This pattern is associated with asymptotic properties of high-order gravity (g-) modes. Our seismic modelling made simultaneously with the mode identification shows that dipole axisymmetric modes best fit the observations. Evolutionary models are computed with MESA code and pulsational models with the linear non-adiabatic code employing the traditional approximation to include the effects of rotation. The problem of mode excitation is discussed. We confirm that significant modification is indispensable to explain an instability of both pressure and gravity modes in the observed frequency ranges of KIC 3240411.

Recent re-determination of stellar atmospheric parameters for a sample of stars observed during the Kepler mission allowed to enlarge the number of Kepler B-type stars. We present the detailed frequency analysis for all these objects. All stars exhibit pulsational variability with maximum amplitudes at frequencies corresponding to high-order g modes. Peaks that could be identified with low-order p/g modes are also extracted for a few stars. We identified some patters in the oscillation spectra that can be associated with the period spacings that can results from the asymptotic nature of the detected pulsational modes. We also tentatively confront the observed oscillation characteristics with predictions from linear nonadiabatic computations of stellar pulsations. For high-order g modes the traditional approximation was employed to include the effects of rotation on the frequency values and mode instability.

We determine instability domains on the Hertzsprung-Russel diagram for rotating main sequence stars with masses 2-20 M . The effects of the Coriolis force are treated in the framework of the traditional approximation. High-order g-modes with the harmonic degrees, , up to 4 and mixed gravity-Rossby modes with |m| up to 4 are considered. Including the effects of rotation results in wider instability strips for a given comparing to the non-rotating case and in an extension of the pulsational instability to hotter and more massive models. We present results for the fixed value of the initial rotation velocity as well as for the fixed ratio of the angular rotation frequency to its critical value. Moreover, we check how the initial hydrogen abundance, metallicity, overshooting from the convective core and the opacity data affect the pulsational instability domains. The effect of rotation on the period spacing is also discussed.

Results of mode identification and seismic modelling of the β Cep/SBP star 12 Lacertae are presented. Using data on the multi-colour photometry and radial velocity variations, we determine or constrain the mode degree, ℓ, for all pulsational frequencies. Including the effects of rotation, we show that the dominant frequency, ν 1 , is most likely a pure ℓ = 1 mode and the low frequency, ν A , is a dipole retrograde mode. We construct a set of seismic models which fit two pulsational frequencies corresponding to the modes ℓ = 0, p 1 and ℓ = 1, g 1 and reproduce also the complex amplitude of the bolometric flux variations, f , for both frequencies simultaneously. Some of these seismic models reproduce also the frequency ν A , as a mode ℓ = 1, g 13 or g 14 , and its empirical values of f . Moreover, it was possible to find a model fitting the six 12 Lac frequencies (the first five and ν A ), only if the rotational splitting was calculated for a velocity of V rot ≈ 75 km/s. In the next step, we check the effects of model atmospheres, opacity data, chemical mixture and opacity enhancement. Our results show that the OP tables are preferred and an increase of opacities in the Z−bump spoils the concordance of the empirical and theoretical values of f .

We present the results of complex seismic analysis of the prototype star SX Phoenicis. This analysis consists of a simultaneous fitting of the two radial-mode frequencies, the corresponding values of the bolometric flux amplitude (the parameter f) and of the intrinsic mode amplitude ϵ. The effects of various parameters as well as the opacity data are examined. With each opacity table it is possible to find seismic models that reproduce the two observed frequencies with masses allowed by evolutionary models appropriate for the observed values of the effective temperature and luminosity. All seismic models are in the post-main sequence phase. The OPAL and OP seismic models are in hydrogen shell-burning phase and the OPLIB seismic model has just finished an overall contraction and starts to burn hydrogen in a shell. The OP and OPLIB models are less likely due to the requirement of high initial hydrogen abundance (X0 = 0.75) and too high metallicity (Z ≈ 0.004) as for a Population II star. The fitting of the parameter f, whose empirical values are derived from multi-colour photometric observations, provides constraints on the efficiency of convective transport in the outer layers of the star and on the microturbulent velocity in the atmosphere. Our complex seismic analysis with each opacity data indicates low to moderately efficient convection in the star’s envelope, described by the mixing length parameter of αMLT ∈ (0.0,  0.7), and the microturbulent velocity in the atmosphere of about ξt ∈ (4,  8) km s−1.