Related papers: Towards a pure ZZ Ceti instability strip
White dwarfs correspond to the final stages of stellar evolution of solar-type stars. In these objects, production of energy by nuclear burning has ended which means that a white dwarf simply cools down over the course of the next billion…
Analyzing all 120 s and 20 s light curves obtained by the TESS satellite up to Sector 69 - the end of the fifth year of observations - for all known white dwarfs and white dwarf candidates up to G=17.5 mag, we report the discovery of 32 new…
We present a dedicated search for new pulsating helium-atmosphere (DBV) white dwarfs from the Sloan Digital Sky Survey using the McDonald 2.1m Otto Struve Telescope. In total we observed 55 DB and DBA white dwarfs with spectroscopic…
$\delta$ Scuti stars are hot, rapid rotators and are a poorly understood class of pulsators. Asteroseismology provides the only means with which to probe their interior dynamics. However, their complex and unexplained oscillation patterns…
Under the Nainital-Cape Survey, eight $\delta\,$Scuti type pulsators have been discovered with the pulsation periods in the range of several minutes to few hours. In order to understand these observed pulsational variabilities, we have…
We accurately identify and classify the variability of A-F stars in the southern continuous viewing zone of the TESS satellite. The brightness limit was set to 10 mag to ensure the utmost reliability of our results and allow for…
Theoretical estimates of the rates of radial pulsation period change in Galactic Cepheids with initial masses 5.5M_\odot <= Mzams <= 13M_\odot, chemical composition X=0.7, Z=0.02 and periods 1.5 day <= P <= 100 day are obtained from…
We report the discovery of two new accreting pulsating white dwarf stars amongst the cataclysmic variables of the Sloan Digital Sky Survey: SDSSJ074531.91+453829.5 and SDSSJ091945.10+085710.0. We observe high amplitude non-sinusoidal…
We studied 89 A- and F-type members of the Pleiades open cluster, including five escaped members. We measured projected rotational velocities (v sin i) for 49 stars and confirmed that stellar rotation causes a broadening of the main…
As white-dwarf (WD) stars cool, they go through one or more stages of $g$(gravity)-mode pulsational instability, becoming multiperiodic variable stars. Stars passing through these instability domains allow astronomers to study their…
Recent progress in the studies of pulsating variable stars is summarized from an observational point of view. A number of unexpected phenomena have been revealed in the case of pulsators in the classical instability strip. These discoveries…
The spectra arising from the disks of nova-like variables show many of the features seen in stellar atmospheres. They are typically modelled either from an appropriated weighted set of stellar atmospheres or a disk atmosphere with energy is…
Using CCD photometry obtained by the EROS collaboration in 1991-1993, we have discovered an LMC variable star with a light curve that is oscillating with a mean period of $\sim 14$ days and an amplitude of $\sim$ 0.3 mag. The oscillations…
Planetary systems hold the imprint of the formation and of the evolution of planets especially at young ages, and in particular at the stage when the gas has dissipated leaving mostly secondary dust grains. The dynamical perturbation of…
We report the discovery of the second pulsating hydrogen-rich (DA) white dwarf in the $Kepler$ field, KIC11911480. It was selected from the $Kepler$-INT Survey (KIS) on the basis of its colours and its variable nature was confirmed using…
We report on the discovery of six new ZZ Ceti stars. They were selected as candidates based on preparatory photometric observations of objects from the Hamburg Quasar Survey (HQS), and based on the spectra of the Supernova Ia Progenitor…
Using our non-local time-dependent theory of convection, the linear non-adiabatic oscillations of 10 evolutionary model series with masses of 1--3M$_\odot$ are calculated. The results show that there is a red giant instability strip in the…
We examine the severe disagreement between the number of predicted and observed pulsation modes for Delta Scuti stars. The selection of nonradial modes trapped in the outer envelope is considered on the basis of kinetic energy arguments.…
Almost all pulsars with anomalous positive $\ddot \Omega $ measurements (corresponding to anomalous braking indices in the range 5$<n<$100), including all the pulsars with observed large glitches ($\Delta\Omega/\Omega$ $>$ 10$^{-7}$) as…
We study the frequency distributions of Delta Scuti stars observed by the Kepler satellite in short-cadence mode. To minimize errors in the estimated stellar parameters, we divided the instability strip into ten regions and determined the…