The Tarantula Massive Binary Monitoring V. R 144: a wind-eclipsing binary with a total mass > 140 Msun
T. Shenar, H. Sana, P. Marchant, B. Pablo, N. Richardson, A. F. J. Moffat, T. Van Reeth, R. H. Barba, D. M. Bowman, P. Broos, P. A. Crowther, J. S. Clark, A. de… 展开作者
T. Shenar, H. Sana, P. Marchant, B. Pablo, N. Richardson, A. F. J. Moffat, T. Van Reeth, R. H. Barba, D. M. Bowman, P. Broos, P. A. Crowther, J. S. Clark, A. de Koter, S. E. de Mink, K. Dsilva, G. Graefener, I. D. Howarth, N. Langer, L. Mahy, J. Maiz Apellaniz, A. M. T. Pollock, F. R. N. Schneider, L. Townsley, J. S. Vink
备注：
Accepted to A&A on the April 06 2021. 17 pages + 5 page appendix. Version 28.10.2021: corrected typo in Eq. (2); numerator and denominator were inversed on RHS (only typo; no impact on results)
R 144 is the visually brightest WR star in the Large Magellanic Cloud (LMC). R 144 was reported to be a binary, making it potentially the most massive binary thus observed. We perform a comprehensive spectral, photometric, orbital, and polarimetric analysis of R 144.
R 144 is an eccentric (e=0.51) 74.2-d binary comprising two relatively evolved (age~2 Myr), H-rich WR stars. The hotter primary (WN5/6h, T=50 kK) and the cooler secondary (WN6/7h,T=45kK) have nearly equal masses. The combination of low rotation and H-depletion observed in the system is well reproduced by contemporary evolution models that include boosted mass-loss at the upper-mass end. The systemic velocity of R 144 and its relative isolation suggest that it was ejected as a runaway from the neighbouring R 136 cluster. The optical light-curve shows a clear orbital modulation that can be well explained as a combination of two processes: excess emission stemming from wind-wind collisions and double wind eclipses. Our light-curve model implies an orbital inclination of i=60.4+-1.5deg, resulting in accurately constrained dynamical masses of 74+-4 and 69+-4 Msun. Assuming that both binary components are core H-burning, these masses are difficult to reconcile with the derived luminosities (logL1,2 = 6.44, 6.39 [Lsun]), which correspond to evolutionary masses of the order of 110 and 100Msun, respectively. Taken at face value, our results imply that both stars have high classical Eddington factors of Gamma_e = 0.78+-0.1. If the stars are on the main sequence, their derived radii (~25Rsun) suggest that they are only slightly inflated, even at this high Eddington factor. Alternatively, the stars could be core-He burning, strongly inflated from the regular size of classical Wolf-Rayet stars (~1Rsun), a scenario that could help resolve the observed mass discrepancy.
We report the discovery that R139 in 30 Doradus is a massive spectroscopic binary system. Multi-epoch optical spectroscopy of R139 was obtained as part of the VLT-FLAMES Tarantula Survey, revealing a double-lined system. The two components are of similar spectral types; the primary exhibits strong C III 4650 emission and is classified as an O6.5 Iafc supergiant, while the secondary is an O6 Iaf supergiant. The radial-velocity variations indicate a highly eccentric orbit with a period of 153.9 days. Photometry obtained with the Faulkes Telescope South shows no evidence for significant variabili…
We present a study of the recent star formation of 30 Doradus in the Large Magellanic Cloud (LMC) using the panchromatic imaging survey Hubble Tarantula Treasury Project (HTTP). In this paper we focus on the stars within 20 pc of the center of the massive ionizing cluster of 30 Doradus, NGC 2070. We recovered the star formation history by comparing deep optical and NIR color-magnitude diagrams (CMDs) with state-of-the-art synthetic CMDs generated with the latest PARSEC models, which include all stellar phases from pre-main sequence to post- main sequence. For the first time in this region we a…
V498 Cyg is an early-B-type binary known to show eclipses on a period of 3.48 d, and two sets of spectral lines. We present the discovery of a second set of eclipses, on a 1.44-d period, in the light curve of this object from the Transiting Exoplanet Survey Satellite (TESS). We develop a model of the light curve to simultaneously fit the properties of both eclipsing binaries and apply this to the TESS observations. We are able to fit the light curve of the fainter system well, but the light curve fit for the brighter system is unable to reproduce either its asymmetric primary eclipse or its ch…
The VLT-FLAMES Tarantula Survey has observed hundreds of O-type stars in the 30 Doradus region of the Large Magellanic Cloud (LMC). We study the properties of 105 apparently single O-type dwarfs. To determine stellar and wind parameters, we used the IACOB-GBAT package, an automatic procedure based on a large grid of atmospheric models calculated with the FASTWIND code. In addition to classical techniques, we applied the Bayesian BONNSAI tool to estimate evolutionary masses. We provide a new calibration of effective temperature vs. spectral type for O-type dwarfs in the LMC, based on our homoge…
The influence of stellar activity on the fundamental properties of stars around and below 1 Msun is not well understood. We aim to determine absolute dimensions and abundances for the solar-type detached eclipsing binary V636 Cen. The results are based on uvby light curves, uvby-beta standard photometry, radial velocity observations, and high-resolution spectra. Masses and radii that are precise to 0.5% have been established for the components of V636 Cen. The 0.85 Msun secondary component is moderately active with starspots and CaII H and K emission, and the 1.05 Msun primary shows signs of a…
Context. The nearby multiple system delta Velorum contains a widely detached eclipsing binary and a third component. Aims. We take advantage of this system offering the opportunity to determine the set of fundamental parameters (masses, luminosities, and radii) of three coeval stars with sufficient precision to test models of stellar evolution. Methods. Extensive high-resolution spectroscopy is analyzed by the broadening function technique to provide the first spectroscopic orbit of the eclipsing pair. Simultaneous analysis of the spectroscopic data and the SMEI satellite light curve is perfor…
We report the discovery and characterisation of a new M-dwarf binary, with component masses and radii of M1 = 0.244 -0.003/+0.003 Msun, R1 = 0.261 -0.009/+0.006 Rsun, M2 = 0.179 -0.001/+0.002 Msun, R2 = 0.218 -0.011/+0.007 Rsun, and orbital period of ~4.1 days. The M-dwarf binary HATS551-027 (LP 837-20) was identified as an eclipsing binary by the HATSouth survey, and characterised by a series of high precision photometric observations of the eclipse events, and spectroscopic determinations of the atmospheric parameters and radial velocity orbits. HATS551-027 is one of few systems with both st…
We present the first SB2 orbital solution and disentanglement of the massive Wolf-Rayet binary R145 (P = 159d) located in the Large Magellanic Cloud. The primary was claimed to have a stellar mass greater than 300Msun, making it a candidate for the most massive star known. While the primary is a known late type, H-rich Wolf-Rayet star (WN6h), the secondary could not be so far unambiguously detected. Using moderate resolution spectra, we are able to derive accurate radial velocities for both components. By performing simultaneous orbital and polarimetric analyses, we derive the complete set of …
V453 Cyg is an eclipsing binary containing 14 Msun and 11 Msun stars in an eccentric short-period orbit. We have discovered $β$ Cep-type pulsations in this system using TESS data. We identify seven significant pulsation frequencies, between 2.37 and 10.51 d$^{-1}$, in the primary star. These include six frequencies which are separated by yet significantly offset from harmonics of the orbital frequency, indicating they are tidally-perturbed modes. We have determined the physical properties of the system to high precision: V453 Cyg A is the first $β$ Cep pulsator with a precise mass measurement.…
We examine the possibility that very massive stars greatly exceeding the commonly adopted stellar mass limit of 150 Msun may be present in young star clusters in the local universe. We identify ten candidate clusters, some of which may host stars with masses up to 600 Msun formed via runaway collisions. We estimate the probabilities of these very massive stars being in eclipsing binaries to be >30%. Although most of these systems cannot be resolved at present, their transits can be detected at distances of 3 Mpc even under the contamination of the background cluster light, due to the large ass…
We present an analysis of the high-mass eclipsing binary system VV Ori based on photometry from the TESS satellite. The primary star (B1V, 9.5 Msun) shows beta Cephei pulsations and the secondary (B7V, 3.8 Msun) is possibly a slowly-pulsating B star. We detect 51 significant oscillation frequencies, including two multiplets with separations equal to the orbital frequency, indicating that the pulsations are tidally perturbed. We analyse the TESS light curve and published radial velocities to determine the physical properties of the system. Both stars are only the second of their pulsation type …
$ζ$ Phoenicis is a bright binary system containing B6V and B8V stars. It has deep total and annular eclipses, a slightly eccentric orbit with a period of 1.669 d, apsidal motion and a third body on a wider orbit. The Transiting Exoplanet Survey Satellite light curve and published radial velocities of this system are analysed to determine masses of 3.91 +/- 0.06 Msun and 2.54 +/- 0.03 Msun and radii of 2.84 +/- 0.02 Rsun and 1.89 +/- 0.01 Rsun. The resulting distance to the system is in agreement with its trigonometric parallax. The physical properties of the stars, with the exception of the ef…
An eclipsing binary with an orbital period of 62 days has been discovered in HD 328058 and studied by UBVIcHalpha photometry. Combining the results of light curve modelling with existing stellar models and known B3-shell spectral type of the primary star then allowed a reliable estimation of the mass, radius and effective temperature of both components: about 6.9 Msun, 5.2 Rsun and 17600 K for the primary star, and about 0.78 Msun, 1.20 Rsun and 56000 K for the hot subdwarf companion of type sdO. Obviously, this binary has been created by mass transfer of the envelope of the sdO progenitor to …
V455 Aur is a detached eclipsing binary containing two F-stars in a 3.15-d orbit with a small eccentricity. Its eclipses were discovered in data from the Hipparcos satellite and a spectroscopic orbit was obtained by Griffin (2001, 2013). Griffin found a long-term variation of the systemic velocity of the eclipsing system due to a third body in a highly eccentric orbit (e = 0.73) with a period of 4200 d. We have used these data, the light curve of V455 Aur from the TESS satellite, and the Gaia EDR3 parallax to determine the physical properties of the components of the system to high precision. …
HIP96515A is a double-lined spectroscopic binary with a visual companion (HIP96515B) at 8.6 arcsec. It is included in the SACY catalog as a potential young star and classified as an eclipsing binary in the ASAS Catalog. We have analyzed spectroscopic and photometric observations of the triple system. The high-resolution optical spectrum of HIP96515A has been used to derive a mass ratio, M_2/M_1, close to 0.9, with the SB2 components showing spectral types of M1 and M2. The ASAS and Hipparcos light-curves of HIP96515A show periodic variations with P=2.3456 days, confirming that HIP96515A is an …
A first solution for the eclipsing binary TYC 4481-358-1 has been found by combining the results of BVIc-photometry with known stellar models and stellar spectral energy distributions (SEDs). The binary shows total and annular eclipses in a circular 90-days orbit. Masses, radii and effective temperatures have been derived: about 3.01 Msun, 14.29 Rsun and 4950 K for the giant, and about 2.39 Msun, 2.39 Rsun and 9600 K for the dwarf. The peculiar dwarf is discolored and shows a Teff - passband dependence from 9000 K in the Ic to 9800 K in the B band. The giant is in its final stage of core heliu…
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 a detailed study of the F-type detached eclipsing binary BK Peg, based on new photometric and spectroscopic observations. The two components, which have evolved to the upper half of the main-sequence band, are quite different with masses and radii of (1.414 +/- 0.007 Msun, 1.988 +/- 0.008 Rsun) and (1.257 +/- 0.005 Msun, 1.474 +/- 0.017 Rsun), respectively. The 5.49 day period orbit of BK Peg is slightly eccentric (e = 0.053). The measured rotational velocities are 16.6 +/- 0.2 (primary) and 13.4 +/- 0.2 (secondary) km/s. For the secondary component this corresponds to (pseudo)synch…
We present high-speed, three-colour photometry of the eclipsing dwarf nova KIS J192748.53+444724.5 which is located in the Kepler field. Our data reveal sharp features corresponding to the eclipses of the accreting white dwarf followed by the bright spot where the gas stream joins the accretion disc. We determine the system parameters via a parameterized model of the eclipse fitted to the observed lightcurve. We obtain a mass ratio of q = 0.570 +/- 0.011 and an orbital inclination of 84.6 +/- 0.3 degrees. The primary mass is M_w = 0.69 +/- 0.07 Msun. The donor star's mass and radius are found …
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…
We present spectroscopic and photometric analysis of the eclipsing binary KIC\,7385478. We find that the system is formed by F1V + K4III-IV components. Combining results from analysis of spectroscopic data and $Kepler$ photometry, we calculate masses and radii of the primary and the secondary components as M$_{1}$ = 1.71 $\pm$ 0.08 \Msun, M$_{2}$ = 0.37 $\pm$ 0.04 \Msun~ and R$_{1}$ = 1.59 $\pm$ 0.03\Rsun, R$_{2}$ = 1.90 $\pm$ 0.03\Rsun, respectively. Position of the primary component in HR diagram is in the region of $γ$ Doradus type pulsators and residuals from light curve modeling exhibit a…
Using multicolour photometry we have confirmed the binary nature of the new W-type W UMa eclipsing binary VSX J053024.8+842243 and established its primary eclipse ephemeris to be HJD = 2455924.38150(26) + 0.4322929(1) * E. Using the light curve modelling code PHOEBE and published data on the evolution of W-type contact binaries we found the primary and secondary components to have masses 0.50 Msun and 1.44 Msun, radii 0.87 Rsun and 1.42 Rsun, luminosities 0.98 Lsun and 1.91 Lsun, temperatures 6145 K and 5702 K and binary orbit inclination 59.4°. We found the distance to the binary to be 511 pa…
In this paper, we present standard Johnson UBV photometry of the eclipsing binary BD+36 3317 which is known as a member of Delta Lyrae (Stephenson 1) cluster. We determined colors and brightness of the system, calculated E(B - V) color excess. We discovered that the system shows total eclipse in secondary minimum. Using this advantage, we found that the primary component of the system has B9 - A0 spectral type. Although there is no published orbital solution, we tried to estimate the physical properties of the system from simultaneous analysis of UBV light curves with 2003 version of Wilson-De…
Eclipsing binary stars provide highly accurate measurements of the fundamental physical properties of stars. They therefore serve as stringent tests of the predictions of evolutionary models upon which most stellar age determinations are based. Models generally perform very well in predicting coeval ages for eclipsing binaries with main-sequence components more massive than ~1.2 Msun; relative ages are good to ~5% or better in this mass regime. Low-mass main-sequence stars (M < 0.8 Msun) reveal large discrepancies in the model predicted ages, primarily due to magnetic activity in the observed …
Spectroscopic observations of the low-mass eclipsing binary NSVS 11868841 have been obtained and the radial velocities were derived for both components. The masses and radii determined for the components are $M_1$ =0.870$\pm$0.074\Msun, $M_2$=0.607$\pm$0.053\Msun and $R_1$ =0.983 $\pm$0.030 \Rsun, $R_2$ =0.901$\pm$0.026 \Rsun. Both the primary and secondary stars' radii are 10 \% and 57\% larger than those of zero-age-main-sequence stars with the same masses. This discrepancy may be arisen from the large spot coverage of both stars. We collected absolute parameters of 21 low mass double-lined …
We present new photometric and spectroscopic observations for 2M 1533+3759 (= NSVS 07826147). It has an orbital period of 0.16177042 day, significantly longer than the 2.3--3.0 hour periods of the other known eclipsing sdB+dM systems. Spectroscopic analysis of the hot primary yields Teff = 29230 +/- 125 K, log g = 5.58 +/- 0.03 and log N(He)/N(H) = -2.37 +/- 0.05. The sdB velocity amplitude is K1 = 71.1 +/- 1.0 km/s. The only detectable light contribution from the secondary is due to the surprisingly strong reflection effect. Light curve modeling produced several solutions corresponding to dif…
We report the discovery of the sixth known eclipsing double white dwarf (WD) system, SDSS J1152+0248, with a 2.3968 +/- 0.0003 h orbital period, in data from the Kepler Mission's K2 continuation. Analysing and modelling the K2 data together with ground-based fast photometry, spectroscopy, and radial-velocity measurements, we determine that the primary is a DA-type WD with mass M1 = 0.47 +/- 0.11 Msun, radius R1 = 0.0197 +/- 0.0035 Rsun, and cooling age t1 = 52 +/- 36 Myr. No lines are detected, to within our sensitivity, from the secondary WD, but it is likely also of type DA. Its central surf…
We present the visual orbit of the double-lined eclipsing binary, HD 185912, from long baseline interferometry with the CHARA Array. We also obtain echelle spectra from the Apache Point observatory to update the spectroscopic orbital solution and analyze new photometry from Burggraaff et al. to model the eclipses. By combining the spectroscopic and visual orbital solutions, we find component masses of M1 = 1.361 +/- 0.004 Msun and M2 = 1.331 +/- 0.004 Msun, and a distance of d = 40.75 +/- 0.30 pc from orbital parallax. From the light curve solution, we find component radii of R1 = 1.348 +/- 0.…
We report long-termed UBVRIRcIc photometry of the highly eccentric 12.04 day detached eclipsing binary V490 Sct (V =13.1, B9.5+A0, e = 0.40), which we use to determine its relative and absolute parameters. The absolute masses, radii, and temperatures are Ma = 2.33+/-0.1 Msun, Ra = 1.91+/-0.04 Rsun, and Ta = 9960+/-60 K for the primary and Mb = 2.24+/-0.1 Msun, Rb = 1.86+/-0.04 Rsun, and Tb = 9700+/-80 K for the secondary. The system displays a slow periastron advance that is dominated by general relativity (GR). Our measurement, dw/dt = 0.86 deg/century, is 32% less then the expected rate, dw/…
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…
V1022 Cas has been known as a spectroscopic binary for a century. It was found to be eclipsing based on photometry from the Hipparcos satellite, and an astrometric orbit was recently obtained from near-infrared interferometry. We present the first high-precision measurement of the radii of the stars based on light curves obtained by the TESS satellite. Combined with published radial velocities from high-resolution spectra, we measure the masses of the stars to be 1.626 +/- 0.001 Msun and 1.609 +/- 0.001 Msun, and the radii to be 2.591 +/- 0.026 Rsun and 2.472 +/- 0.027 Rsun. The 12.16-d orbit …
Six mid-eclipse times of the eclipsing binary XZ And are obtained, which are analysed together with others collected from the literature. Two sets of cyclic variations with periods of 33.43 and 100.4 yr are found if a double-Keplerian model is used to fit the data. The 1:3 ratio of the periods suggests that both cyclic variations arise from dynamic motions of two companions rather than magnetic activity of the eclipsing pair. According to the double-Keplerian model, the companions have the masses of about 1.32 Msun and 1.33 Msun, respectively. Comparing the total masses of the eclipsing pair o…
Eclipsing binaries are important tools for studying stellar evolution and stellar interiors. Their accurate fundamental parameters are used to test evolutionary models, and systems showing apsidal motion can also be used to test the model's internal structure predictions. For this purpose, we present a photometric and spectroscopic analysis of the eclipsing binary BW Aquarii, an evolved F-type binary with slow apsidal motion. We model the K2 C3 light curve using the Eclipsing Light Curve code to determine several orbital and stellar parameters, as well as measure the eclipse times to determine…
V505 Per is a detached eclipsing binary containing two F5 V stars in a 4.22-d circular orbit. We use a light curve from the TESS satellite and published radial velocity measurements to establish the properties of the system to high precision. The masses of the stars are 1.275 +/- 0.004 Msun and 1.258 +/- 0.003 Msun, and their radii are 1.294 +/- 0.002 Rsun and 1.264 +/- 0.002 Rsun. Adding published effective temperature estimates, we precisely measure the luminosities and absolute bolometric magnitudes of the stars, and the distance to the system. The distance is slightly shorter than that obt…
We present ULTRACAM photometry and X-Shooter spectroscopy of the eclipsing double white dwarf binary CSS 41177, the only such system that is also a double-lined spectroscopic binary. Combined modelling of the light curves and radial velocities yield masses and radii for both white dwarfs without the need to assume mass-radius relations. We find that the primary white dwarf has a mass of M1 = 0.38(2) Msun and a radius of R1 = 0.0222(4) Rsun. The secondary white dwarf's mass and radius are M2 = 0.32(1) Msun and R2 = 0.0207(4) Rsun, and its temperature and surface gravity (T2 = 11678(313) K, log(…
ZZ Boo is an F-type detached eclipsing binary system containing two almost-identical stars on a circular orbit with a period of 4.992 d. We analyse light curves from two sectors of observations with the Transiting Exoplanet Survey Satellite (TESS) and two published sets of radial velocities of the component stars to determine their physical properties to high precision. We find masses of 1.558 +/- 0.008 Msun and 1.599 +/- 0.012 Msun, and radii of 2.063 +/- 0.006 Rsun and 2.205 +/- 0.006 Rsun. The similarity in the primary and secondary eclipse depths has led to confusion in the past. The high …
We report photometric observations of the eclipsing close binary CSS21055 (SDSS J141126+200911) that strongly suggest that the companion to the carbon-oxygen white dwarf is a brown dwarf with a mass between 0.030 and 0.074 Msun. The measured orbital period is 121.73min and the totality of the eclipse lasts 125s. If confirmed, CSS21055 would be the first detached eclipsing WD+BD binary. Spectroscopy in the eclipse could provide information about the companion's evolutionary state and atmospheric structure.
AN Cam is a little-studied eclipsing binary containing somewhat evolved components in an orbit with a period of 21.0 d and an eccentricity of 0.47. A spectroscopic orbit based on photoelectric radial velocities was published in 1977. AN Cam has been observed using the TESS satellite in three sectors: the data were obtained in long-cadence mode and cover nine eclipses. By modelling these data and published radial velocities we obtain masses of 1.380 +/- 0.021 Msun and 1.402 +/- 0.025 Msun, and radii of 2.159 +/- 0.012 Rsun and 2.646 +/- 0.014 Rsun. We also derive a precise orbital ephemeris fro…
V578 Mon is an eclipsing binary system in which both stars have masses above 10 Msun determined with an accuracy better than 3%. It is one of only five such massive eclipsing binaries known that also possess eccentric orbits and measured apsidal motions, thus making it an important benchmark for theoretical stellar evolution models. However, recently reported determinations of the radii of V578 Mon differ significantly from previously reported values. We reanalyze the published data for V578 Mon and trace the discrepancy to the use of an incorrect formulation for the stellar potentials in the …
The eclipsing binary T-Cyg1-12664 was observed both spectroscopically and photometrically. Radial velocities of both components and ground-based VRI light curves were obtained. The Kepler's R-data and radial velocities for the system were analysed simultaneously. Masses and radii were obtained as 0.680$\pm$0.021 M$_{\odot}$ and 0.613$\pm$0.007 R$_{\odot}$for the primary and 0.341$\pm$0.012M$_{\odot}$ and 0.897$\pm$0.012R$_{\odot}$ for the secondary star. The distance to the system was estimated as 127$\pm$14 pc. The observed wave-like distortion at out-of-eclipse is modeled with two separate s…
We present comprehensive spectroscopic and photometric analysis of the detached eclipsing binary KIC 12418816, which is composed of two very similar and young main sequence stars of spectral type K0 on a circular orbit. Combining spectroscopic and photometric modelling, we find masses and radii of the components as 0.88+-0.06 Msun and 0.84+-0.05 Msun, and 0.85+-0.02 Rsun, and 0.84+-0.02 Rsun for the primary and the secondary, respectively. Both components exhibit narrow emission features superposed on the cores of the Ca II H&K lines, while H alpha and H beta photospheric absoprtion is more co…
HS 0705+6700 is a short-period (P=2.3 hours), close binary containing a hot sdB-type primary and a fully convective secondary. We have monitored this eclipsing binary for more than 2 years and as a result, 32 times of light minimum were obtained. Based on our new eclipse times together with these compiled from the literature, it is discovered that the O-C curve of HS 0705+6700 shows a cyclic variation with a period of 7.15 years and a semiamplitude of 92.4 s. The periodic change was analyzed for the light-travel time effect that may be due to the presence of a tertiary companion. The mass of t…
We present an analysis of NGC2204-S892 -- a new detached eclipsing binary composed of two late K dwarfs. Based on three photometric campaigns launched in 2008 we obtained 5 light curves (3 in V, 1 in B and 1 in I), and derived an orbital period of 0.451780+-0.000001 d. We also obtained 20 VLT/UVES spectra, enabling accurate radial velocity measurements. The derived masses and radii of the components (m1 = 0.733 +-0.005 Msun and R1 = 0.72 +-0.01 Rsun; m2 = 0.662 +-0.005 Msun and R2 = 0.68 \+-0.02 Rsun) are consistent with the empirical mass-radius relationship established recently for lower mai…
We observed spectroscopically the eclipsing binary system T-Cyg1-01385 in order to determine physical properties of the components. The double-lined nature of the system is revealed for the first time and the radial velocities are obtained for both stars. We have derived masses, radii and luminosities for both components. Analyses of the radial velocities and the KeplerCam and the T$r$ES light curves yielded masses of M$_1$=1.059$\pm$0.032 \Msun ~and M$_2$=0.342$\pm$0.017 {\Msun} and radii of R$_1$=1.989$\pm$0.022 {\Rsun} and R$_2$=0.457$\pm$0.013 {\Rsun}. Locations of the low-mass companion i…
V1388 Ori is an early-B type detached eclipsing binary whose physical properties have previously been measured from dedicated spectroscopy and a ground-based survey light curve. We reconsider the properties of the system using newly-available light curves from the Transiting Exoplanet Survey Satellite (TESS). We discover two frequencies in the system, at 2.99 d$^{-1}$ and 4.00 d$^{-1}$ which are probably due to beta Cephei or slowly-pulsating B-star pulsations. A large number of additional significant frequencies exist at multiples of the orbital frequency, 0.4572 d$^{-1}$. We are not able to …
We use a combination of X-shooter spectroscopy, ULTRACAM high-speed photometry and SOFI near-infrared photometry to measure the masses and radii of both components of the eclipsing post common envelope binaries SDSS J1212-0123 and GK Vir. For both systems we measure the gravitational redshift of the white dwarf and combine it with light curve model fits to determine the inclinations, masses and radii. For SDSS J1212-0123 we find a white dwarf mass and radius of 0.439 +/- 0.002 Msun and 0.0168 +/- 0.0003 Rsun, and a secondary star mass and radius of 0.273 +/- 0.002 Msun and 0.306 +/- 0.007 Rsun…
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 +…
KX Cancri is an eclipsing binary containing two G-type stars with an orbital period of 31.2 d and an eccentricity of 0.47. These qualities make it a promising candidate for a benchmark solar-type binary system. We analyse the first light curve of this system to have complete coverage of both primary and secondary eclipses, obtained using the Transiting Exoplanet Survey Satellite (TESS). We augment these data with published radial velocities and measure the masses to be 1.134 +/- 0.003 Msun and 1.124 +/- 0.005 Msun and the radii to be 1.053 +/- 0.006 Rsun and 1.059 +/- 0.005 Rsun. A ratio of th…
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…
The observational mass-radius relation of main sequence stars with masses between ~0.3 and 1.0 Msun reveals deviations between the stellar radii predicted by models and the observed radii of stars in detached binaries. We generate an accurate physical model of the low-mass eclipsing binary T-Cyg1-12664 in the Kepler mission field to measure the physical parameters of its components and to compare them with the prediction of theoretical stellar evolution models. We analyze the Kepler mission light curve of T-Cyg1-12664 to accurately measure the times and phases of the primary and secondary ecli…
The eclipsing binary LL Aqr consists of two late-type stars in an eccentric orbit with a period of 20.17 d. We use an extensive light curve from the SuperWASP survey augmented by published radial velocities and UBV light curves to measure the physical properties of the system. The primary star has a mass of 1.167 +/- 0.009 Msun and a radius of 1.305 +/- 0.007 Rsun. The secondary star is an analogue of the Sun, with a mass and radius of 1.014 +/- 0.006 Msun and 0.990 +/- 0.008 Rsun respectively. The system shows no signs of stellar activity: the upper limit on spot-induced rotational modulation…
We present the results of our spectroscopic and photometric analysis of two newly discovered low-mass detached eclipsing binaries found in the All-Sky Automated Survey (ASAS) catalogue: ASAS J093814-0104.4 and ASAS J212954-5620.1. Using the GIRAFFE instrument on the 1.9-m Radcliffe telescope at SAAO and the UCLES spectrograph on the 3.9-m Anglo-Australian Telescope, we obtained high-resolution spectra of both objects and derived their radial velocities (RVs) at various orbital phases. The RVs of both objects were measured with the TODCOR technique using synthetic template spectra as references…
