Related papers: Post-common envelope binary stars: Radiative Levit…
Blue large-amplitude pulsators (BLAPs) are a newly discovered group of compact pulsating stars whose origin needs to be explained. Of the existing evolutionary scenarios that could lead to the formation of BLAPs, there are two in which…
Asteroseismology is a very useful tool for exploring the stellar interiors and evolutionary status and for determining stellar fundamental parameters, such as stellar mass, radius, surface gravity, and the stellar mean density. In the…
It is shown for the first time that the stripped helium stars with masses 2 to 7 solar mass which are formed in close binary systems in the so-called case B of mass-exchange and retained low-mass hydrogen-helium envelopes, experience…
A significant fraction of all metal-poor stars are carbon-rich. Most of these carbon-enhanced metal-poor (CEMP) stars also show enhancement in elements produced mainly by the s-process (CEMP-s stars) and evidence suggests that the origin of…
We evolve stellar models to study the common envelope (CE) interaction of an early asymptotic giant branch star of initial mass $5\,\rm M_{\odot}$ with a companion star of mass ranging from $0.1$ to $2\,\rm M_{\odot}$. We model the CE as a…
We suggest that the vigorous core convection during core helium flash on the tip of the red giant branch (RGB) of low mass stars excites waves that carry energy to the envelope and inflate it for few years to increase the number of extreme…
Numerical computations of stellar oscillations for models representative of B-type stars predict fewer modes to be excited than observations reveal from modern space-based photometric data. One shortcoming of state-of-the-art evolution…
Blue Large-Amplitude Pulsators (BLAPs) are rare short-period ($\lesssim$80 min) pulsating variable stars exhibiting large-amplitude brightness variations (typically between 0.1 and 0.4 mag). As a recently discovered class of radial-mode…
Blue Large-Amplitude Pulsators (BLAPs) form a mysterious class of variable stars with typical periods of tens of minutes and amplitudes above 0.1 mag. In this work, we present results of a variability search focused on timescales shorter…
Low mass white dwarfs are the remnants of disrupted red giant stars in binary millisecond pulsars and other exotic binary star systems. Some low mass white dwarfs cool rapidly, while others stay bright for millions of years due to stable…
The discovery of pulsations in some low-mass white dwarfs, including the so-called extremely low-mass white dwarfs, has opened the unprecedented opportunity of probing the internal structure of these ancient stars. We present a detailed…
Regular intrinsic brightness variations observed in many stars are caused by pulsations. These pulsations provide information on the global and structural parameters of the star. The pulsation periods range from seconds to years, depending…
Common-envelope (CE) evolution is an outstanding open problem in stellar evolution, critical to the formation of compact binaries including gravitational-wave sources. In the ``classical'' isolated binary evolution scenario for double…
During the post-main sequence evolution massive stars pass through several short-lived phases, in which they experience enhanced mass loss in the form of clumped winds and mass ejection events of unclear origin. The discovery that stars…
Blue Large Amplitude Pulsators (BLAPs) are blue stars showing high amplitude (>0.2 mag) pulsations on a timescale of a few tens of mins. They form a new class of variable star recently discovered using OGLE data. It has lead to a number of…
We present 3D radiation hydrodynamics simulations of common-envelope (CE) evolution involving a 12 solar mass red supergiant donor and a 3 solar mass companion. Existing 3D simulations are predominantly adiabatic, focusing strongly on…
In this work, we search the OGLE-IV outer Galactic bulge fields for short-period variable objects. The investigation focuses on unexplored timescales roughly below one hour in an area containing about 700 million stellar sources down to…
The discovery via gravitational waves of binary black hole systems with total masses greater than $60M_\odot$ has raised interesting questions for stellar evolution theory. Among the most promising formation channels for these systems is…
Blue large-amplitude pulsators (BLAPs), a recently classified type of variable stars, are evolved objects likely formed through interactions between stars in a binary system. However, only two BLAPs with stellar companions have been…
The unstable mass transfer situation in binary systems will asymptotically cause the adiabatic expansion of the donor star and finally lead to the common envelope phase. This process could happen in helium binary systems once the helium…