Related papers: Chemical evolution of high-mass stars in close bin…
We present spectroscopic observations of the double-lined early type eclipsing binary V1898\,Cyg. The radial velocities were obtained by means of the cross-correlation technique. Analyses of the BV light curves and RVs led to determination…
PG1159 stars are hot, hydrogen-deficient (pre-) white dwarfs with atmospheres mainly composed of helium, carbon, and oxygen. The unusual surface chemistry is the result of a late helium-shell flash. Observed element abundances enable us to…
HARPS spectra with S/N > 600 for 21 solar twin stars are used to determine very precise (sigma ~ 0.01 dex) differential abundances of C, O, Na, Mg, Al, Si, S, Ca, Ti, Cr, Fe, Ni, Zn, and Y in order to see how well [X/Fe] is correlated with…
The hydrogen-deficiency in extremely hot post-AGB stars of spectral class PG1159 is probably caused by a (very) late helium-shell flash or a AGB final thermal pulse that consumes the hydrogen envelope, exposing the usually-hidden intershell…
Early-type magnetic stars are rarely found in close binary systems. No such objects were known in eclipsing binaries prior to this study. Here we investigated the eclipsing, spectroscopic double-lined binary HD66051, which exhibits…
Binary star systems are assumed to be co-natal and coeval, thus to have identical chemical composition. In this work we aim to test the hypothesis that there is a connection between observed element abundance patterns and the formation of…
Eclipsing binary systems have a unique feature, which enables scientists to obtain precise fundamental star parameters, which opens to greater area of astrophysics studies. In this study, we have derived the fundamental parameters, the…
This study presents a comprehensive analysis of the detached binary system V570\,Per through combined photometric, spectroscopic, and astrometric observations. By disentangling the composite spectra, precise fundamental parameters and…
We report extensive spectroscopic and differential V-band photometric observations of the 18.4-day detached double-lined eclipsing binary LV Her (F9V), which has the highest eccentricity (e = 0.613) among the systems with well-measured…
Binary stars undergoing mass transfer provide unique laboratories for testing stellar evolution. Here, we present a comprehensive photometric and spectroscopic analysis of the semi-detached system ET Cru. Using spectral disentangling, we…
We report on detailed spectroscopic studies performed for the secondary star in the black hole binary (micro-quasar) V4641 Sgr in order to examine its surface chemical composition and to see if its surface shows any signature of pollution…
V501 Her is a well detached G3 eclipsing binary star with a period of 8.597687 days for which we have determined very accurate light and radial-velocity curves by using robotic telescopes. Results of these data indicate that the component…
Symbiotic stars (SySt) are binaries composed of a star in the later stages of evolution and a stellar remnant. The enhanced mass-loss from the giant drives interacting mass exchange and makes these systems laboratories for understanding…
The atmospheric parameters of the components of the 16Cygni binary system, in which the secondary has a gas giant planet detected, are measured accurately using high quality observational data. Abundances relative to solar are obtained for…
Models of stellar structure and evolution can be constrained by measuring accurate parameters of detached eclipsing binaries in open clusters. Multiple binary stars provide the means to determine helium abundances in these old stellar…
The theory of binary evolution predicts that many massive stars should lose their hydrogen-rich envelopes via interaction with a companion -- revealing hot helium stars with masses of $\sim$2--8M$_{\odot}$. However, only one candidate…
As potential progenitors of several exotic phenomena including gravitational wave sources, magnetic stars, and Be stars, close massive binary systems probe a crucial area of the parameter space in massive star evolution. Despite the…
The method of spectral disentangling has now created the opportunity for studying the chemical composition in previously inaccessible components of binary and multiple stars. This in turn makes it possible to trace their chemical evolution,…
Earlier measurements of the masses and radii of the detached eclipsing binary V20 in the open cluster NGC 6791 were accurate enough to demonstrate that there are significant differences between current stellar models. Here we improve on…
The majority of massive stars are located in binary or multiple star systems. Compared to single stars, these objects pose additional challenges to quantitative analyses based on model atmospheres. In particular, little information is…