Related papers: Massive B-type pulsators in low-metallicity enviro…
We search for effects of metallicity on B and Be stars in the Small and Large Magellanic Clouds (SMC and LMC) and in the Milky Way (MW). We extend our previous analysis of B and Be stars populations in the LMC to the SMC. The rotational…
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…
We present key sample results of a systematic survey of the pulsation properties of models of hot B subdwarfs. We use equilibrium structures taken from detailed evolutionary sequences of solar metallicity (Z = 0.02) supplemented by grids of…
We present results of the instability analysis of the post-main sequence massive star models against radial and nonradial pulsations. We confirm that both p- and g-modes can be excited by the $\kappa$-mechanism acting in the metal opacity…
This paper reports the discovery of new slowly pulsating B-type stars. Based on the photometric, spectral, and astrometric data of TESS, LAMOST, and Gaia surveys, we have found 286 new slowly pulsating B-type stars (SPB stars) and 21…
We present a comprehensive seismic study of the three pulsating stars of $\beta$ Cep/SPB type: $\nu$ Eridani, 12 Lacertae and $\gamma$ Pegasi. Models with the modified mean opacity profile are constructed in order to account for both the…
The analysis of the light curves of 48 B-type stars observed by Kepler is presented. Among these are 15 pulsating stars, all of which show low frequencies characteristic of SPB stars. Seven of these stars also show a few weak, isolated high…
Recent theoretical predictions for low metallicity massive stars predict that these stars should have drastically reduced equatorial winds (mass loss) while on the main sequence, and as such should retain most of their angular momentum.…
At low metallicity, B-type stars show lower loss of mass and, therefore, angular momentum so that it is expected that there are more Be stars in the Magellanic Clouds than in the Milky Way. However, till now, searches for Be stars were only…
Pulsations in subdwarf B stars are attributed to radiative levitation of iron-group elements in the stellar envelope. Until now, only iron diffusion is accounted for in stellar models used for sdB seismology. However, nickel has also been…
Slowly pulsating B stars (SPB) and $\gamma$ Dor stars pulsate in high-order gravity (g-) modes. The frequencies of g-modes are sensitive to the detailed structure and evolution history of stars having convective cores. Receding convective…
Hot subdwarf B stars (sdBs) are the stripped cores of red giants located at the bluest extension of the horizontal branch. Several different kinds of pulsators are found among those stars. The mechanism that drives those pulsations is well…
We present ultraviolet spectra from the Space Telescope Imaging Spectrograph (STIS) of 12 early B-type stars in the Small Magellanic Cloud (SMC), comprising 9 supergiants and 3 giants. A morphological comparison with Galactic analogues is…
The rich oscillation spectra determined for the two stars, Nu Eridani and 12 Lacertae, present an interesting challenge to stellar modelling. The stars are hybrid objects showing a number of modes at frequencies typical for Beta Cep stars…
I examine the stability of retrograde mixed modes in rotating B-type stars. These modes can be regarded as a hybrid between the Rossby modes that arise from conservation of vorticity, and the Poincare modes that are gravity waves modified…
The identification of non-radial g-mode oscillations as the cause of variability in cool subdwarf B stars (PG1716 variables) has been frustrated by a 5 000 K discrepancy between the observed and theoretical blue edge of the instability…
Aims. In order to better model massive B-type stars, we need to understand the physical processes taking place in slowly pulsating B (SPB) stars, chemically peculiar Bp stars, and non-pulsating normal B stars co-existing in the same part of…
We present possible explanations of pulsations in early B-type main sequence stars which arise purely from the excitation of gravity modes. There are three stars with this type of oscillations detected from the BRITE light curves: $\kappa$…
We collected a sample of ten hitherto unidentified SPB stars with the aim of describing their pulsational properties and identifying pulsational modes. Photometric time series data from various surveys were collected and analyzed using…
Recent observational and theoretical results emphasize the potential significance of magnetic fields for structure, evolution, and environment of massive stars. Depending on their spectral and photometric behavior, the upper main-sequence…