We present the results of our spectroscopic observations of eight detached eclipsing binaries (DEBs), selected from the $Kepler$ Eclipsing Binary Catalog. Radial velocities (RVs) were calculated from high resolution spectra obtained with the HIDES pectrograph, attached to the 1.88-m telescope of the Okayama Astrophysical Observatory, and were used to characterize the targets in combination with the $Kepler$ light curves. For each binary we obtained a full set of orbital and physical parameters, reaching precision below 3% in masses and radii for 5 pairs. By comparing our results with theoretical models, we assess the distance, age and evolutionary status of the researched objects. We also study eclipse timing variations of selected objects, and identify a new system with a $γ$Dor pulsator. Two systems are triples, and show lines coming from three components. In one case the motion of the outer star and the perturbation in the RVs of the inner binary are clearly visible and periodical, which allows us to directly calculate the mass of the third star, and inclination of the outer orbit. In the second case we only see a clear motion of the tertiary, and investigate two scenarios: that it is a linear trend coming from the orbital motion around the inner binary, and that it is caused by a planetary mass companion. When possible, we also compare our results with the literature, and conclude that only by combining photometry with RVs it is possible to obtain correct physical parameters of both components of a DEB.
We present phase-resolved spectroscopy and extensive survey photometry of the detached eclipsing binary system XY Cet, which is composed of two metallic-lined stars. We measure their masses to be 1.773 +/- 0.016 and 1.615 +/- 0.014 Msun and their radii to be 1.873 +/- 0.035 and 1.773 +/- 0.029 Rsun, resulting in logarithmic surface gravities of 4.142 +/- 0.016 and 4.149 +/- 0.014 (cgs). We determine effective temperatures of 7870 +/- 115 and 7620 +/- 125 K. The projected rotational velocities are 34.4 +/- 0.4 and 34.1 +/- 0.4 km/s, which are close to synchronous. Theoretical models cannot matc…
Eclipsing binaries are vital for directly determining stellar parameters without reliance on models or scaling relations. Spectroscopically derived parameters of detached and semi-detached binaries allow us to determine component masses that can inform theories of stellar and binary evolution. Here we present moderate resolution ground-based spectra of stars in close binary systems with and without (detected) tertiary companions observed by NASA's Kepler mission and analyzed for eclipse timing variations. We obtain radial velocities and spectroscopic orbits for five single-lined and 35 double-…
We present results of our spectroscopic observations of nine detached eclipsing binaries (DEBs), selected from the $Kepler$ Eclipsing Binary Catalog, that only show one set of spectral lines. Radial velocities (RVs) were calculated from the high resolution spectra obtained with the HIDES instrument, attached to the 1.88-m telescope at the Okayama Astrophysical Observatory, and from the public APOGEE archive. In our sample we found five single-lined binaries, with one component dominating the spectrum. The orbital and light curve solutions were found for four of them, and compared with isochron…
The bright binary system YZ Cassiopeiae is a remarkable laboratory for studying the Am phenomenon. It consists of a metallic-lined A2 star and an F2 dwarf on a circular orbit, which undergo total and annular eclipses. We present an analysis of 15 published light curves and 42 new high-quality echelle spectra, resulting in measurements of the masses, radii, effective temperatures and photospheric chemical abundances of the two stars. The masses and radii are measured to 0.5% precision: M_A = 2.263 +/- 0.012 Msun, M_B = 1.325 +/- 0.007 Msun, R_A = 2.525 +/- 0.011 Rsun and R_B = 1.331 +/- 0.006 R…
We present the latest results of our spectroscopic observations and refined modelling of a sample of detached eclipsing binaries (DEBs), selected from the $Kepler$} Eclipsing Binary Catalog, that are also double-lined spectroscopic binaries (SB2). New high resolution spectra obtained with the HIDES spectrograph, attached to the 1.88-m telescope of the Okayama Astrophysical Observatory supplemented the previous observations, allowing to improve physical parameters of some systems, and characterize three previously omitted. All the obtained radial velocities (RVs) were combined with $Kepler$ pho…
Compact Hierarchical Triples (CHT) are systems with the tertiary star orbiting the inner binary in an orbit shorter than 1000 days. CHT with an eclipsing binary as its inner binary can help us extract a multitude of information about all three stars in the system. In this study, we use independent observational techniques to estimate the orbital, stellar, and atmospheric parameters of two triple-lined CHT: BD+442258 and KIC06525196. We find that the masses of stars in BD+442258 are $1.011\pm0.029 M_{\odot}$, $0.941\pm0.033 M_{\odot}$, and $0.907\pm0.065 M_{\odot}$ while in KIC06525196 the esti…
The most accurate stellar astrophysical parameters were collected from the solutions of the light and the radial velocity curves of 257 detached double-lined eclipsing binaries in the Milky Way. The catalogue contains masses, radii, surface gravities, effective temperatures, luminosities, projected rotational velocities of the component stars and the orbital parameters. The number of stars with accurate parameters increased 67 per cent in comparison to the most recent similar collection by Torres et al. (2010). Distributions of some basic parameters were investigated. The ranges of effective t…
Based on luminosity contributions, we develop a spectroscopic modelling method to derive atmospheric parameters of component stars in binary systems. The method is designed for those spectra of binaries which show double-lined features due to the radial velocities differences between the component stars. We first derive the orbital parameters and the stellar radii by solving the light and radial velocity curves. Then the luminosity contributions in different phases can be calculated. The synthesised double-lined spectra model is constructed by superposing theoretical single-star spectra accord…
Detached eclipsing binaries allow stellar masses and radii to be measured with unrivalled accuracy. While inspecting light curves obtained with the Transiting Exoplanet Survey Satellite (TESS), we noticed that the A0 III star $α$ Dra shows clear and well-separated primary and secondary eclipses. This star is known to be a single-lined spectroscopic binary, with a period of 51.5 d and an eccentricity of 0.43. The currently available TESS observations cover two 27-d sectors and the light curve shows a primary eclipse (depth 9%) and a secondary eclipse (depth 2%), separated in time by 38.5 days. …
We have analyzed the long period, double-lined eclipsing binary system OGLE SMC113.3 4007 (SC10 137844) in the SMC. The binary lies in the north-eastern part of the galaxy and consists of two evolved, well detached, non-active G8 giants. The orbit is eccentric with e = 0.311 and the orbital period is 371.6 days. Using extensive high-resolution spectroscopic and multi-color photometric data we have determined a true distance modulus of the system of m-M=18.83 +/- 0.02 (statistical) +/- 0.05 (systematic) mag using a surface brightness - color relation for giant stars. This method is very insensi…
We present the results of age determination for galactic B-type main sequence stars which are components of double-lined eclipsing binaries. Only detached systems are considered. We analyze 38 binary systems that meet such criteria. The analysis is based on evolutionary computations and we consider that the age is determined if there is a common value from the radius-age diagrams and the agreement in the position of both components in the Hertzsprung-Russel diagram. In some cases, to meet these two conditions, it was necessary to adjust the value of the metallicity, Z or/and the parameter of o…
Using Liverpool Telescope+RISE photometry we identify the 2.78 hour period binary star CSS 41177 as a detached eclipsing double white dwarf binary with a 21,100K primary star and a 10,500K secondary star. This makes CSS 41177 only the second known eclipsing double white dwarf binary after NLTT 11748. The 2 minute long primary eclipse is 40% deep and the secondary eclipse 10% deep. From Gemini+GMOS spectroscopy we measure the radial velocities of both components of the binary from the Hα absorption line cores. These measurements, combined with the light curve information, yield white dwarf mass…
The photometric and spectroscopic data for three double-lined detached eclipsing binaries were collected from the photometric and spectral surveys. The light and radial velocity curves of each binary system were simultaneously analyzed by using Wilson-Devinney (WD) code, and the absolute physical and orbital parameters of these binaries were derived. The masses of both components of ASASSN-V J063123.82+192341.9 were found to be $M_1 = 1.088 \pm 0.016$ and $M_2 = 0.883 \pm 0.016\ M_{\odot}$; and those of ASAS J011416+0426.4 were determined to be $M_1 = 0.934 \pm 0.046$ and $M_2 = 0.754 \pm 0.04…
A high fraction of massive stars are found to be binaries but only a few of them are reported as photometrically variable. By studying the populations of SB2 in the 30 Doradus region, we found a subset of them that have photometry from the OGLE project and that display variations in their light curves related to orbital motions. The goal of this study is to determine the dynamical masses and radii of the 26 binary components to investigate the mass-discrepancy problem and to provide an empirical mass-luminosity relation for the LMC. We use the PHOEBE programme to perform a systematic analysis …
The Araucaria project: High-precision orbital parallaxes and masses of binary stars. I. VLTI/GRAVITY observations of ten double-lined spectroscopic binaries
We present an extensive set of photometry and radial velocities for the detached eclipsing binary KV 29 in the intermediate-aged open cluster M11 (NGC 6705). Spectroscopy shows that the system is double-lined and all available evidence (proper motion, photometry, and position on the CMD) indicates it is a member of the cluster. We find the period of the binary to be $4.64276\pm0.00001$ days. We find masses $3.604^{+0.002}_{-0.011}M_\odot$ and $1.837^{+0.001}_{-0.006}M_\odot$, and radii $5.392^{+0.018}_{-0.035}R_\odot$ and $1.656^{+0.007}_{-0.044}R_\odot$ for the primary and secondary stars, re…
The young binary system HD 350731 is a noteworthy laboratory for studying early-type binaries with similar components. We present here the analysis of differential multi-color photometric and spectroscopic observations for the double-lined detached system. Accurate absolute parameters were determined from the simultaneous solution of light and radial velocity curves for the first time. HD 350731 consists of two B8V-type components having masses and radii respectively of $M_{1}=2.91\pm0.13$ M$_{\odot}$, $M_{2}=2.80\pm0.14$ M$_{\odot}$, $R_{1}= 2.11 \pm0.05$ R$_{\odot}$ and $R_{2}=2.07\pm0.05$ R…
CPD-54 810 is a double-lined detached eclipsing binary containing two mid-F type dwarfs on an eccentric 26-day orbit. We perform a combined analysis of the extensive photometry obtained by the TESS space mission along with previously published observations to obtain a full orbital and physical solution for the system. We measure the following model-independent masses and radii: M1 = 1.3094+/-0.0051 Msun, M2 = 1.0896+/-0.0034 Msun, R1 = 1.9288+/-0.0030 Rsun, and R2 = 1.1815+/-0.0037 Rsun. We employ a Bayesian approach to obtain the bolometric flux for both stars from observed magnitudes, colour…
We present the Kepler photometric light-variation analysis of the late-type double-lined binary system V568 Lyr that is in the field of the high metallicity old open cluster NGC 6791. The radial velocity and the high-quality short-cadence light curve of the system are analysed simultaneously. The masses, radii and luminosities of the component stars are $M_1 = 1.0886\pm0.0031\, M{\odot}$, $M_2 = 0.8292 \pm 0.0026\, M{\odot}$, $R_1 = 1.4203\pm 0.0058\, R{\odot}$, $R_2 = 0.7997 \pm 0.0015\, R{\odot}$, $L_1 = 1.85\pm 0.15\, L{\odot}$, $L_2 = 0.292 \pm 0.018\, L{\odot}$ and their separation is $a …
W UMi is a near contact, semi-detached, double-lined eclipsing binary star with an orbital period of 1.7 days. Simultaneous analysis of new BVR multi-color light curves and radial velocity data yields the main astrophysical parameters of the binary and its component stars. We determined mass and radius to be M$_{1}$=3.22$\pm$0.08 M$_{\odot}$, R$_{1}$=3.63$\pm$0.04 R$_{\odot}$ for the primary star and M$_{2}$=1.44$\pm$0.05 M$_{\odot}$, R$_{2}$=3.09$\pm$0.03 R$_{\odot}$ for the secondary star. Based on analysis of mid-eclipse times, variation in the orbital period is represented by a cyclic term…
Context: One of the greatest uncertainties in modelling the mass-exchange phases during the evolution of a binary system is the amount of mass and angular momentum that has been lost from the system. To constrain this problem, a favourable, evolved and detached real binary system is valuable as an example of the end result of this process. Aims: We study the 52-day post-mass-exchange eclipsing binary V643 Ori from complete uvby light curves and high-resolution spectra. V643 Ori is a double-lined, circular orbit, synchronized binary showing total primary eclipses. Results: We determine accurate…
We analyze extensive BVRI photometry and radial velocity measurements for three double-lined deeply-eclipsing binary stars in the field of the old open cluster NGC 7142. The short period (P = 1.9096825 d) detached binary V375 Cep is a high probability cluster member, and has a total eclipse of the secondary star. The characteristics of the primary star (M=1.288+/-0.017 Sun) at the cluster turnoff indicate an age of 3.6 Gyr (with a random uncertainty of 0.25 Gyr), consistent with earlier analysis of the color-magnitude diagram. The secondary star (M = 0.871+/-0.008 Msun) is not expected to have…
We analyze extensive BVR_cI_c time-series photometry and radial-velocity measurements for WOCS 40007 (Auner 259; KIC 5113053), a double-lined detached eclipsing binary and a member of the open cluster NGC 6819. Utilizing photometric observations from the 1-meter telescope at Mount Laguna Observatory and spectra from the WIYN 3.5-meter telescope, we measure precise and accurate masses (~1.6% uncertainty) and radii (~0.5%) for the binary components. In addition, we discover a third star orbiting the binary with a period greater than 3000 days using radial velocities and Kepler eclipse timings. B…
Eclipsing binary systems with components that pulsate in gravity modes ($g$ modes) allow for simultaneous and independent constraints of the chemical mixing profiles of stars. We aim to assemble a sample of $g$-mode pulsators in detached eclipsing binaries with the purpose of finding good candidates for future evolutionary and asteroseismic modelling. In addition, we present a case study of the eclipsing binary KIC9850387, identified as our most promising candidate. We selected all of the detached eclipsing binaries in the Kepler eclipsing binary catalogue and performed a visual inspection to …
Reported are spectroscopic observations of 15 candidates for Kepler primary asteroseismic targets and 14 other stars in the Kepler field, carried out at three observatories (see the footnote). For all these stars, the radial velocities, effective temperature, surface gravity, metallicity, and the projected rotational velocity are derived from two separate sets of data by means of two independent methods. In addition, MK type is estimated from one of these sets of data. Three stars, HIP 94335, HIP 94734, and HIP 94743, are found to have variable radial-velocity. For HIP 94335 = FL Lyr, a well-k…
The 3rd data release of the Gaia mission includes orbital solutions for $> 10^5$ single-lined spectroscopic binaries, representing more than an order of magnitude increase in sample size over all previous studies. This dataset is a treasure trove for searches for quiescent black hole + normal star binaries. We investigate one population of black hole candidate binaries highlighted in the data release: sources near the main sequence in the color-magnitude diagram (CMD) with dynamically-inferred companion masses $M_2$ larger than the CMD-inferred mass of the luminous star. We model light curves,…
In this study, the distributions of the double-lined detached binaries (DBs) on the planes of mass-luminosity, mass radius and mass-effective temperature have been studied. We improved the classical mass-luminosity relation based on the database of DBs by Eker et al. (2004a). With accurate observational data available to us, a method for improving effective temperatures for eclipsing binaries with accurate masses and radii were suggested.
Accurate stellar parameters of individual objects in binary systems are essential to constrain the effects of binarity on stellar evolution. These parameters serve as a prerequisite to probing existing and future theoretical evolutionary models. We aim to derive the atmospheric parameters of the 31 SB2s in the TMBM sample. This sample, composed of detached, semi-detached and contact systems with at least one of the components classified as an O star, is an excellent test-bed to study how binarity can impact our knowledge of the evolution of massive stars. 32 epochs of FLAMES/GIRAFFE spectra ar…
We report the discovery by the HATNet survey of HAT-TR-318-007, a $P = 3.34395390\pm0.00000020$ d period detached double-lined M-dwarf binary with total secondary eclipses. We combine radial velocity (RV) measurements from TRES/FLWO 1.5 m, and time-series photometry from HATNet, FLWO 1.2 m, BOS 0.8 m and NASA K2 Campaign 5, to determine the masses and radii of the component stars: $M_{A} = 0.448\pm0.011$ $M_{\odot}$, $M_{B} = 0.2721^{+0.0041}_{-0.0042}$ $M_{\odot}$, $R_{A} = 0.4548^{+0.0035}_{-0.0036}$ $R_{\odot}$, and $R_{B} = 0.2913^{+0.0023}_{-0.0024}$ $R_{\odot}$. We obtained a FIRE/Magell…
We report the discovery of a detached double white dwarf binary with an orbital period of $\approx20.6\,\rm minutes$, PTF J053332.05+020911.6. The visible object in this binary, PTF J0533+0209B, is a $\approx 0.17\,M_\odot$ mass white dwarf with a helium-dominated atmosphere containing traces of hydrogen (DBA). This object exhibits ellipsoidal variations due to tidal deformation, and is the visible component in a single-lined spectroscopic binary with a velocity semi-amplitude of $K_B=618.7\pm6.9 \, \rm km \, s^{-1}$. We have detected significant orbital decay due to the emission of gravitatio…
The recent discovery and analysis of a classical Cepheid in the well detached, double-lined, eclipsing binary OGLE-LMC-CEP0227, has provided the first determination of the dynamical mass of a classical Cepheid variable to an unprecedented 1% accuracy. We show here that modern stellar evolution models widely employed to study Galactic and extragalactic stellar systems, are able to match simultaneously mass and radius (and effective temperature) of the two components with a single value for the age of the system, without any specific fine-tuning. Our conclusion is that there is no discrepancy be…
Surface brightness -- colour relations (SBCRs) are very useful tools for predicting the angular diameters of stars. They offer the possibility to calculate very precise spectrophotometric distances by the eclipsing binary method or the Baade-Wesselink method. Double-lined Detached Eclipsing Binary stars (SB2 DEBs) with precisely known trigonometric parallaxes allow for a calibration of SBCRs with unprecedented precision. In order to improve such calibrations, it is important to enlarge the calibration sample of suitable eclipsing binaries with very precisely determined physical parameters. We …
The purpose of this work is to extend a sample of accurately modeled, benchmark-grade eclipsing binaries with accurately determined masses and radii. We select four "well-behaved" Kepler binaries, KIC2306740, KIC4076952, KIC5193386 and KIC5288543, each with at least 8 double-lined spectra from the apogee instrument that is part of the Sloan Digital Sky Surveys III and IV, and from the Hobby-Eberly High Resolution Spectrograph. We obtain masses and radii with uncertainties of 2.5% or less for all four systems. Three of these systems have orbital periods longer than 9 days, and thus populate an …
We report extensive differential V-band photometry and high-resolution spectroscopy for the 1.14 day, detached, double-lined eclipsing binary BT Vul (F0+F7). Our radial-velocity monitoring and light curve analysis lead to absolute masses and radii of M1 = 1.5439 +/- 0.0098 MSun and R1 = 1.536 +/- 0.018 RSun for the primary, and M2 = 1.2196 +/- 0.0080 MSun and R2 = 1.151 +/- 0.029 RSun for the secondary. The effective temperatures are 7270 +/- 150 K and 6260 +/- 180 K, respectively. Both stars are rapid rotators, and the orbit is circular. A comparison with stellar evolution models from the MIS…
We present the absolute properties of the double-lined eclipsing binary KIC 6206751 exhibiting multiperiodic pulsations. The ${\it Kepler}$ light curve of this system was simultaneously solved with the radial-velocity data given by Matson et al. (2017). The results indicate that the binary star is a short-period semi-detached system with fundamental parameters of $M_1$ = 1.66$\pm$0.04 M$_\odot$, $M_2$ = 0.215$\pm$0.006 M$_\odot$, $R_1$ = 1.53$\pm$0.02 R$_\odot$, $R_2$ = 1.33$\pm$0.02 R$_\odot$, $L_1$ = 5.0$\pm$0.6 L$_\odot$, and $L_2$ = 0.96$\pm$ 0.09 L$_\odot$. We applied multiple frequency a…
We present new spectroscopic observations of the early type, double-lined eclipsing binary V446\,Cep. The radial velocities and the photometric data obtained by $Hipparcos$ were analysed for deriving the astrophysical parameters of the components. Masses and radii were determined as M$_p$=17.94$\pm$1.16 M$_{\odot}$ and R$_p$=8.33$\pm$0.29 R$_{\odot}$, M$_s$=2.64$\pm$0.30 M$_{\odot}$ and R$_s$=2.13$\pm$0.10 R$_{\odot}$ for the components of V446\,Cep. Our analyses show that V446\,Cep is a detached Algol-type system. Based on the position of the components plotted on the theoretical Hertzsprung-…
CW Cep is an early B-type eclipsing binary with mass measurement precisions better than 1 \%. We report the discovery of pulsation signatures in the TESS time-series data of the system observed during Sectors 17 and 18. Our binary modeling indicates that the target star is a partially-eclipsing detached system with masses of 12.95 $M_\odot$ and 11.88 $M_\odot$ and radii of 5.52 $R_\odot$ and 5.09 $R_\odot$ in an eccentric orbit of $e$ = 0.0305. The distance to the eclipsing system, 928 $\pm$ 36 pc, is much more precise than the Gaia distance of 962 $\pm$ 453 pc. Applying multifrequency analyse…
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 properties. We determine the absolute masses and radii of the components to be M1 = 1.193 +/- 0.010 M(Sun), M2 = 1.1698 +/- 0.0081 M(Sun), R1 = 1.358 +/- 0.012 R(Sun), and R2 = 1.313 +/- 0.011 R(Sun), with fractional errors of 0.9% or better. The effective temperatures are 6060 +/- 150 K and 6030 +/- 150 K, respectively, and the overall metallicity is estimated …
We present absolute physical and orbital parameters for three double-lined detached eclipsing binary systems from the All Sky Automated Survey (ASAS) catalogue with subgiant and giant components. These parameters were derived from archival V-band ASAS photometry and new radial velocities. The radial velocities were calculated from high quality optical spectra we obtained with the 8.2 m Subaru/HDS, ESO 3.6 m/HARPS, 1.9 m Radcliffe/GIRAFFE, CTIO 1.5 m/CHIRON, and 1.2 m Euler/CORALIE using the two-dimensional cross-correlation technique (TODCOR) and synthetic template spectra chosen for every sys…
As part of our study of the old (~2.5 Gyr) open cluster NGC 6819 in the Kepler field, we present photometric (Kepler and ground-based BVRcIc) and spectroscopic observations of the detached eclipsing binary WOCS 24009 (Auner 665; KIC 5023948) with a short orbital period of 3.6 days. WOCS 24009 is a triple-lined system, and we verify that the brightest star is physically orbiting the eclipsing binary using radial velocities and eclipse timing variations. The eclipsing binary components have masses M_B =1.090+/-0.010 Msun and M_C =1.075+/-0.013 Msun, and radii R_B =1.095+/-0.007 Rsun and R_C =1.0…
RR Lyn is a detached eclipsing binary with a 9.95 d orbit containing two A-stars: one metallic-lined and one possibly metal-poor. We use the light curve from the TESS satellite and two sets of published radial velocity measurements to determine the properties of the system to high precision. We find masses of 1.939 +/- 0.007 and 1.510 +/- 0.003 Msun, and radii of 2.564 +/- 0.019 and 1.613 +/- 0.013 Rsun. After adjusting published effective temperatures upwards by 200 K we find a good agreement with theoretical models for a solar chemical composition and an age of 1 Gyr, and a distance slightly…
We present our results of a combined analysis of radial velocity and light curves of a double-lined spectroscopic and eclipsing binary KIC 09246715, observed photometrically by the $Kepler$ satellite, and spectroscopically with the OAO-1.88m telescope with the HIgh-Dispertion Echelle Spectrograph (HIDES). The target was claimed to be composed of two red giants, one of which is showing solar-like oscillations. We have found that the mass and radius of the primary are $M_1=2.169\pm0.024$ M$_\odot$ and $R_1=8.47\pm0.13$ R$_\odot$, and of the secondary: $M_2=2.143\pm0.025$ M$_\odot$ and $R_2=8.18\…
We report follow-up spectroscopic observations of the 1.62 day, K-type, detached, active, near-circular, double-lined eclipsing binary EPIC 219511354 in the open cluster Ruprecht 147, identified previously on the basis of photometric observations from the Kepler/K2 mission. This is the fourth eclipsing system analyzed in this cluster. A combined analysis of the light curve and radial velocities yields accurate masses of M(Aa) = 0.912 +/- 0.013 MSun and M(Ab) = 0.822 +/- 0.010 MSun for the primary (star Aa) and secondary (Ab), along with radii of R(Aa) = 0.920 +/- 0.016 RSun and R(Ab) = 0.851 +…
We report differential photometric observations and radial-velocity measurements of the detached, 1.69-day period, double-lined eclipsing binary AQ Ser. Accurate masses and radii for the components are determined to better than 1.8% and 1.1%, respectively, and are M1 = 1.417 +/- 0.021 MSun, M2 = 1.346 +/- 0.024 MSun, R1 = 2.451 +/- 0.027 RSun, and R2 = 2.281 +/- 0.014 RSun. The temperatures are 6340 +/- 100 K (spectral type F6) and 6430 +/- 100 K (F5), respectively. Both stars are considerably evolved, such that predictions from stellar evolution theory are particularly sensitive to the degree…
We report new spectroscopic and photometric observations of the main-sequence, detached, eccentric, double-lined eclipsing binary V541 Cyg (P = 15.34 days, e = 0.468). Using these observations together with existing measurements we determine the component masses and radii to better than 1% precision: M1 = 2.335 +0.017/-0.013 MSun, M2 = 2.260 +0.016/-0.013 MSun, R1 = 1.859 +0.012/-0.009 RSun, and R2 = 1.808 +0.015/-0.013 RSun. The nearly identical B9.5 stars have estimated temperatures of 10650 +/- 200 K and 10350 +/- 200 K. A comparison of these properties with current stellar evolution models…
We performed a new and accurate fit of light and radial velocity curves of the Large Magellanic Cloud (LMC) Cepheid --OGLE-LMC-CEP-0227-- belonging to a detached double-lined eclipsing binary system. We computed several sets of nonlinear, convective models covering a broad range in stellar mass, effective temperature and in chemical composition. The comparison between theory and observations indicates that current theoretical framework accounts for luminosity --V and I band-- and radial velocity variations over the entire pulsation cycle. Predicted pulsation mass --M=4.14+-0.06 Mo-- and mean e…
We present spectroscopic and photometric solutions for three spotted systems with red giant components. Absolute physical and orbital parameters for these double-lined detached eclipsing binary stars are presented for the first time. These were derived from the V-, and I-band ASAS and WASP photometry, and new radial velocities calculated from high quality optical spectra we obtained with a wide range of spectrographs and using the two-dimensional cross-correlation technique (TODCOR). All of the investigated systems (ASAS J184949-1518.7, BQ Aqr, and V1207 Cen) show the differential evolutionary…
We report our spectroscopic monitoring of the detached, grazing, and slightly eccentric 12-day double-lined eclipsing binary EPIC 219568666 in the old nearby open cluster Ruprecht 147. This is the second eclipsing system to be analyzed in this cluster, following our earlier study of EPIC 219394517. Our analysis of the radial velocities combined with the light curve from the K2 mission yield absolute masses and radii for EPIC 219568666 of M1 = 1.121 +/- 0.013 M(Sun) and R1 = 1.1779 +/- 0.0070 R(Sun) for the F8 primary, and M2 = 0.7334 +/- 0.0050 M(Sun) and R2 = 0.640 +/- 0.017 R(Sun) for the fa…
