Related papers: On X-ray pulsations in beta Cephei-type variables
Short-period binaries represent extreme cases in the generation of stellar coronae via a rotational dynamo. Such stars are important for probing the origin and nature of coronae in the regimes of rapid rotation and activity saturation. VW…
We previously reported a rare class of variable star light curves isolated from a sample of 4.7 million candidate variables from the ATLAS survey. Dubbed `UCBH' light curves, they have broad minima and narrow, symmetrical maxima, with…
As a result of the variability survey in Chi Persei and NGC6910, the number of Beta Cep stars that are members of these two open clusters is increased to twenty stars, nine in NGC6910 and eleven in Chi Persei. We compare pulsational…
Context. Be stars are physically complex systems that continue to challenge theory to understand their rapid rotation, complex variability and decretion disks. $\gamma$ Cassiopeiae ($\gamma$ Cas) is one such star but is even more curious…
The O- and B-type (OB-type) pulsating stars are important objects to study the structure and evolution of massive stars through asteroseismology. A large amount of data from various sky surveys provide an unprecedented opportunity to search…
The majority of magnetic chemically peculiar (mCP) stars exhibit periodic light, magnetic, radio, and spectroscopic variations that can be adequately modelled as a rigidly-rotating main-sequence star with persistent surface structures.…
The prototype of the Beta Cep class of pulsating stars, Beta Cep, rotates relatively slowly, and yet displays episodic Halpha emission. Such behaviour is typical of a classical Be star. For some time this posed a contradiction to our…
The effects of opacities in driving pulsations and extending the pulsation instability region for B-type stars (SPB and $\beta$ Cep variables) have recently been explored by, e.g., Walczak et al. 2015, 2017, Daszynska-Daszkiewicz et al.…
We investigate the short-term optical variability of two gamma Cas analogs, pi Aqr and BZ Cru, thanks to intensive ground-based spectroscopic and space-borne photometric monitorings. For both stars, low-amplitude (mmag) coherent photometric…
We review the nature of the oscillations of main-sequence and supergiant stars of spectral type B. Seismic tuning of the interior structure parameters of the $\beta $Cep stars has been achieved since three years. The results are based on…
Observations with powerful X-ray telescopes, such as XMM-Newton and Chandra, significantly advance our understanding of massive stars. Nearly all early-type stars are X-ray sources. Studies of their X-ray emission provide important…
We carried out a new and sensitive search for long-period variability in the prototype of the Mira class of long-period pulsating variables, o Ceti (Mira A), the closest and brightest Mira variable. We conducted this search using an…
In spite of recent detections of magnetic fields in a number of beta Cephei and slowly pulsating B (SPB) stars, their impact on stellar rotation, pulsations, and element diffusion is not sufficiently studied yet. The reason for this is the…
The NASA Kepler spacecraft data revealed a large number of multimode nonradially pulsating gamma Dor and delta Sct variable star candidates. The high precision long time-series photometry makes it possible to study amplitude variations of…
Most O and many B stars show unexplained cyclical variability in their spectral lines, i.e. modulation on the rotational timescale, but not strictly periodic. The variability occurs in the so-called discrete absorption components (DACs)…
The eighth part of the OGLE-III Catalog of Variable Stars (OIII-CVS) contains type II Cepheids in the Small Magellanic Cloud (SMC). The sample consists of 43 objects, including 17 BL Her, 17 W Vir and 9 RV Tau stars (first examples ever…
Bright and eclipsing, the high-mass X-ray binary Vela X-1 offers a unique opportunity to study accretion onto a neutron star from clumpy winds of O/B stars and to disentangle the complex accretion geometry of these systems. In Chandra-HETGS…
We undertook a multisite photometric campaign for the Beta Cephei star Nu Eridani. More than 600 hours of differential photoelectric uvyV photometry were obtained with 11 telescopes during 148 clear nights. The frequency analysis of our…
During the last two years we have received long time-series photometric observations of bright (V mag < 8) main-sequence A- and B-type stars observed by the NASA TESS spacecraft and the Austria-Poland-Canada BRITE satellites. Using TESS…
CCD photometry in the V band is presented for 7 field RR Lyrae stars selected from a sample of eight variables which, according to data collected in the literature, are expected to be {\it ab}-type pulsators, to have short periods and hence…