Related papers: A window into $\delta$ Sct stellar interiors: Unde…
HD172189 is a spectroscopic eclipsing binary system with a rapidly-rotating pulsating delta Scuti component. It is also a member of the open cluster IC4756. These combined characteristics make it an excellent laboratory for asteroseismic…
The evolution of binaries consisting of evolved main sequence stars (1 < M_d/Msun < 3.5) with white dwarf companions (0.7 < M_wd/Msun < 1.2) is investigated through the thermal mass transfer phase. Taking into account the stabilizing effect…
St 2-22 is a relatively poorly studied S-type symbiotic system that belongs to a small group of jet-producing systems as a result of disc accretion onto a white dwarf fed by its red giant companion. The goal of this paper is to analyse the…
Many stars exhibit stellar pulsations, favoring them for asteroseismic analyses. Interpreting the oscillations requires some knowledge of the oscillation mode geometry (spherical degree, radial and azimuthal orders). The delta Scuti stars…
We have detected new components in stationary emission lines of SS 433; these are the superbroad components that are low-contrast substrates with a width of 2000--2500 km s-1 in He I $\lambda4922$ and H$\beta$ and 4000--5000 km s-1 in He II…
The chemical composition of stellar photospheres in mass-transferring binary systems is a precious diagnostic of the nucleosynthesis processes that occur deep within stars, and preserves information on the components history. The binary…
Several evolutionary sequences with low--mass secondaries ($M_d $=1.25, 1.5 and 1.7$ M_\odot $) and black hole accretors ($M_{bh} $=5 and 10$ M_\odot$) are calculated. The angular momentum losses due to magnetic braking and gravitational…
A promising formation channel of SMBHs at redshift 6 is the so-called DC model, which posits that a massive seed BH forms through gravitational collapse of a $\sim 10^5~M_\odot$ SMS. We study the evolution of such a SMS growing by rapid…
This paper presents a comprehensive analysis of RR Lep and BF Vel, two short-period semi-detached oscillating Algols (oEA stars), which are shown to be triple systems. Spectral types of their primaries were determined and radial velocities…
We obtained high-resolution spectra and multicolor photometry of V1082 Sgr to study the donor star in this 20.8 hr orbital period binary, which is assumed to be a detached system. We measured the rotational velocity (v sin i = 26.5+/-2.0…
Despite being the most common types of stars in the Galaxy, the physical properties of late M dwarfs are often poorly constrained. A trend of radius inflation compared to evolutionary models has been observed for earlier type M dwarfs in…
In the course of a project to study eclipsing binary stars in vinicity of the Sun, we found that the cooler component of LL Aqr is a solar twin candidate. This is the first known star with properties of a solar twin existing in a…
We present the first modern analysis of two young, eclipsing binaries, EK Cep and HS Her, based on new, ground-based, CCD multicolour light curves as well as the TESS observations, radial velocity curves, and eclipse timing measurements.…
Motivated by recent suggestions that many Be stars form through binary mass transfer, we searched the APOGEE survey for Be stars with bloated, stripped companions. From a well-defined parent sample of 297 Be stars, we identified one…
Mass transfer in binary systems is the key process in the formation of various classes of objects, including merging binary black holes (BBHs) and neutron stars. Orbital evolution during mass transfer depends on how much mass is accreted…
In this paper, we analyze the light variation of KIC 8840638 using high-precision time-series data from $Kepler$ mission. The analysis reveals this target is a new Algol-type eclipsing binary system with a $\delta$ Scuti component, not a…
Classical T Tauri stars (CTTSs) are young stellar objects that accrete materials from their accretion disc influenced by their strong magnetic field. The magnetic pressure truncates the disc at a few stellar radii and forces the material to…
We present the discovery of \thisstar\ (HD 58730), a very low mass ratio ($q \equiv M_2/M_1 \approx 0.07$) eclipsing binary (EB) identified by the Kilodegree Extremely Little Telescope (KELT) survey. We present the discovery light curve and…
We calculate the stellar evolution of both white dwarfs (WDs) in AM CVn binaries with orbital periods of $P_{\mathrm{orb}} \approx 5-70$ minutes. We focus on the cases where the donor starts as a $M_{\mathrm{He}} < 0.2 \, M_{\odot}$ Helium…
The unusual light curve of the massive eclipsing binary W Ser was recently observed with high S/N and fast cadence by the NASA TESS mission. The TESS light curve records two eclipses and relatively fast variations outside of the eclipses.…