Physics Of Eclipsing Binaries Research Articles

The Distribution of Semidetached Binaries. I. An Efficient Pipeline

Semidetached binaries are in the stage of mass transfer and play a crucial role in studying the physics of mass transfer between interacting binaries. Large-scale time-domain surveys provide many light curves of binary systems, while Gaia offers high-precision astrometric data. In this paper, we develop, validate, and apply a pipeline that combines the Markov Chain Monte Carlo method with a forward model and DBSCAN clustering to search for semidetached binaries and estimate the inclination, relative radius, mass ratio, and temperature ratio of each using light curves. We train our model on the mock light curves from Physics of Eclipsing Binaries (PHOEBE), which provides broad coverage of light-curve simulations for semidetached binaries. Applying our pipeline to Transiting Exoplanet Survey Satellite sectors 1–26, we have identified 77 semidetached binary candidates. Utilizing the distance from Gaia, we determine their masses and radii with median fractional uncertainties of ∼26% and ∼7%, respectively. With the added 77 candidates, the catalog of semidetached binaries with orbital parameters has been expanded by approximately 20%. The comparison and statistical results show that our semidetached binary candidates align well with the compiled samples and the PARSEC model in T eff–L and M–R relations. Combined with the literature samples, comparative analysis with stability criteria for conserved mass transfer indicates that ∼97.4% of samples are undergoing nuclear-timescale mass transfer, and two samples (GO Cyg and TIC 454222105) are located within the limits of stability criteria for dynamical- and thermal-timescale mass transfer, and are currently undergoing thermal-timescale mass transfer. Additionally, one system (IR Lyn) is very close to the upper limit of delayed dynamical-timescale mass transfer.

A new look at the YY CrB binary system

This study presented a new analysis for the TESS-observed W Ursae Majoris (W UMa) binary star YY Coronea Borealis (YY CrB). The light curve was analyzed by the PHysics Of Eclipsing BinariEs (PHOEBE) Python version together with the Markov chain Monte Carlo (MCMC) method. The light curve solutions required a hot spot and l3. New eclipse times from the TESS observations were extracted, and the O-C curve of primary and secondary minima showed an anti-correlated manner. In order to study the O-C curve of minima, minima times between 1991 and 2023 were collected. This investigation reported a new linear ephemeris and by fitting a quadratic function to the O-C curve of minima, calculated the orbital period rate of Ṗ≈5.786×10−8dayyear. Assuming mass conservation, a mass exchange rate of Ṁ2=2.472×10−8 calculated from the more massive component to the less massive one. Then, by using the light travel time function, the possible third body was determined in the binary and derived the mass of the third body as 0.498M⊙ with a period of ≃7351.018 days. The O-C curve analysis and the quantity of mass indicate that the presence of a third body is unlikely. This binary is expected to evolve into a broken-contact phase and is a good case to support the thermal relaxation oscillation model.

Light Curve Analysis of the AP Dor Binary System using Ground-based and TESS Observations

The short-period eclipsing binary AP Dor’s first in-depth and multiband photometric solutions are presented. We made use of our eight nights of ground-based opportunity at a southern hemisphere observatory, and twelve sectors of TESS observations. We extracted eight and 1322 minima from our observations and TESS, respectively. We suggest a new linear ephemeris based on the trend of orbital period variations using the Markov chain Monte Carlo (MCMC) approach. The PHysics Of Eclipsing BinariEs (PHOEBE) Python code and the MCMC approach were utilized for the light curve analysis. This system did not require a starspot for the light curve solutions. We calculated the absolute parameters of the system by applying the Gaia DR3 parallax method. The orbital angular momentum (J 0) of AP Dor indicates that this system is located in a region corresponding to contact binaries. According to our results, this system is an overcontact binary system with a mass ratio of 0.584, a fillout factor of 48%, and an inclination of 53°. The positions of component stars in the AP Dor system on the Hertzsprung–Russell diagram are found.

The First Multiband Photometric Light Curve Solutions of the V Gru Binary System from the Southern Hemisphere

The first multiband photometric solutions of the short-period V Gru eclipsing binary from the southern hemisphere are presented in this study. Light curves of the system were observed through BVI filters at the Congarinni Observatory in Australia for 15 nights. In addition to the new ground-based data, we also used the TESS observations in two sectors. We analyzed the light curves of the system using the PHysics Of Eclipsing BinariEs (PHOEBE) 2.4.7 version code to achieve the best accordance with the photometric observations. The solutions suggest that V Gru is a near-contact binary system with q = 1.302(81) mass ratio, f 1 = 0.010(23), f 2 = −0.0.009(21), and i = 73.45(38). We considered the two hot spots on the hotter and cooler components for the light curve analysis. We extracted the minima times from the light curves based on the Markov Chain Monte Carlo (MCMC) approach. Using our new light curves, TESS, and additional literature minima, we computed the ephemeris of V Gru. The system’s eclipse timing variation trend was determined using the MCMC method. This system is a good and challenging case for future studies.

Study of Eclipsing Binary Physical Parameters. Case: CV Boo

Eclipsing binary (EB) is a binary system in which the components are seen eclipsing each other from the Earth. Photometric and spectroscopic observation of EBs show variation on their brightness (light curve) and radial velocity (velocity curve). Light and radial velocity curve analysis provide physical and geometrical parameters of the binary systems and their components, which are very important in stellar evolution studies. These parameters are determined by solving inverse problem, i.e. finding the best-fitting model to the observational curves. Modern EBs modeling programs include detailed physics of stellar atmosphere, geometry, and dynamics of the binary system. One of such models is PHOEBE (PHysics Of Eclipsing BinariEs) 2.3, which offers sophisticated methods to solve the inverse problem. It is solved by computing model curves from initial (estimated) parameters, optimizing them numerically, and sampling the optimized models. We studied CV Boo, a detached EB with a period of 0.847 days, using PHOEBE 2.3. Light curve and radial velocity curves were obtained from the literature. We discuss the steps in finding the solution, present our best solution of the inverse problem, and compare our results with previous studies.

The Photometric Study of Six W UMa Systems and Investigation of the Mass–Radius Relations for Contact Binary Stars

We present the photometric analysis of six short-period systems (EI Oct, V336 TrA, NX Boo, V356 Boo, PS Boo, and V2282 Cyg). This is the first photometric analysis of these systems except for V336 TrA. Observations were conducted for 27 nights at three observatories in the northern and southern hemispheres. We calculated a new ephemeris for each of the systems using our minimum times and additional literature. The Markov Chain Monte Carlo (MCMC) approach was used to determine the eclipse timing variation trends of the systems. We found a likely orbital growth for V336 TrA and PS Boo; four other systems show a linear trend in orbital period changes, which is most likely due to the accumulation of measurement errors in their linear ephemeris parameters. The light curve analysis was performed using the Physics of Eclipsing Binaries (PHOEBE) 2.3.59 version code with the MCMC approach. The absolute parameters of the systems were calculated by using the Gaia Early Data Release 3 (EDR3) parallax. The positions of the systems were also depicted on the Hertzsprung–Russell (H-R) and diagrams. According to a sample, we were able to present relations for the mass–radius (M–R) relationships of contact binary systems. There is also a strong relationship between the mass ratio and the radius ratio in the W UMa systems for which we also provided a new relation. We compared the M–R updated relationships in this study with seven systems in other studies obtained using the spectroscopic method. In addition, we estimated some of the absolute parameters for 1734 EW systems, based on the new relationships.

The First Photometric Study of AH Mic Contact Binary System

The first multi-color light curve analysis of the AH Mic binary system is presented. This system has very few past observations from the southern hemisphere. We extracted the minima times from the light curves based on the Markov Chain Monte Carlo (MCMC) approach and obtained a new ephemeris. To provide modern photometric light curve solutions, we used the Physics of Eclipsing Binaries (PHOEBE) software package and the MCMC approach. Light curve solutions yielded a system temperature ratio of 0.950, and we assumed a cold starspot for the hotter star based on the O’Connell effect. This analysis reveals that AH Mic is a W-subtype W UMa contact system with a fill-out factor of 21.3% and a mass ratio of 2.32. The absolute physical parameters of the components are estimated by using the Gaia Early Data Release 3 (EDR3) parallax method to be M h (M ⊙) = 0.702(26), M c (M ⊙) = 1.629(104), R h (R ⊙) = 0.852(21), R c (R ⊙) = 1.240(28), L h (L ⊙) = 0.618(3) and L c (L ⊙) = 1.067(7). The orbital angular momentum of the AH Mic binary system was found to be 51.866(35). The components’ positions of this system are plotted in the Hertzsprung–Russell diagram.

Binary star detection in the open cluster King 1 field

A rarely studied open cluster, King 1 is observed using the 1.3-m telescope equipped with a 2k × 4k CCD at Vainu Bappu Observatory, India. We analyze the photometric data obtained from CCD observations in both B and V bands. Out of 132 detected stars in the open cluster King 1 field, we have identified four stellar variables, and two among them are reported as newly detected binary systems. The parallax values from Gaia DR2 suggest that the open cluster King 1 is in the background of these two detected binary systems, falling along the same line of sight, giving rise to different parallax values. Periodogram analysis was carried out using Phase Dispersion Minimization (PDM) and the Lomb-Scargle (LS) method for all the detected variables. PHysics Of Eclipsing BinariEs (PHOEBE) is extensively employed to model various stellar parameters of both the detected binary systems. Based on the modeling results obtained from this work, one of the binary systems is reported for the first time as an Eclipsing Detached (ED) and the other as an Eclipsing Contact (EC) binary of W-type W UMa.

A hundred new eclipsing binary system candidates studied in a near-infrared window in the VVV survey

AbstractWe present the first results obtained from an extensive study of eclipsing binary (EB) system candidates recently detected in the VISTA Variables in the Vía Láctea (VVV) near-infrared (NIR) Survey. We analyse the VVV tile d040 in the southern part of the Galactic disc wherein the interstellar reddening is comparatively low, which makes it possible to detect hundreds of new EB candidates. We present here the light curves and the determination of the geometric and physical parameters of the best candidates found in this ‘NIR window’, including 37 contact, 50 detached, and 13 semi-detached EB systems. We infer that the studied systems have an average of the$K_s$amplitudes of$0.8$mag and a median period of 1.22 days where, in general, contact binaries have shorter periods. Using the ‘Physics Of Eclipsing Binaries’ (PHOEBE) interactive interface, which is based on the Wilson and Devinney code, we find that the studied systems have low eccentricities. The studied EBs present mean values of about 5 700 and 4 900 K for the$T_1$and$T_2$components, respectively. The mean mass ratio (q) for the contact EB stars is$\sim$0.44. This new galactic disk sample is a first look at the massive study of NIR EB systems.

First light curve analysis of eclipsing binary system ASAS 185542–0123.1

A very first light curve (LC) analysis of eclipsing binary ASAS 185542–0123.1 is presented. This star is part of our binary star survey project at Bosscha Observatory and also plays an important role as a testing ground for our new robotic telescope. LC of this star was constructed by using LEMON, a semi–automatic photometric pipeline written in Python. We managed to refine orbital period of this system and its time of primary minimum, hence we could update its ephemeris as Min I(HJD) = 2451964.551517 + 1.161607 × E. We also conducted a LC modeling with PHOEBE (PHysics Of Eclipsing BinariEs) software built on top of the widely used WD program. The photometry solutions are mass ratio q = 0.309 ± 0.026, orbital inclination i = 83.15 ± 0.42°, ratio of effective temperatures , and surface potentials for primary and secondary component Ω1 = 4.08 ± 0.16 and Ω2 = 2.71 ± 0.10, respectively. In conclusion, this system is classified as detached eclipsing binary system which has almost similar temperatures between its primary and secondary component. From temperature solution estimation, we have preliminary conclusion that its primary and secondary component has a spectral type of G0/1V + G2/3V, respectively.

Light curve analyses of eclipsing binary system ASAS 172533–1221.4

Using the data taken from our 0.36 m f/7.2 robotic telescope, we performed a very first light curve (LC) analyses of eclipsing binary ASAS 172533-1221.4, one of target stars which is part of program stars in our variable star survey project. The LC of this star was constructed by using LEMON, a semi-automatic photometric pipeline written in Python. We refined a Time of Minima (ToM, T0) and variability period of this system, P and updated its ephemerides as HJD(min I) = 2457200.255578 + 0.678861 * ϕ. The LC modeling of the system was conducted with the PHOEBE (PHysics Of Eclipsing BinariEs) software built on top of the widely used WD program . The assorted LC modeling solutions are shown as follows: mass ratio q = 0.811 ± 0.009, inclination i = 70.62 ± 0.01°, temperature of primary and secondary component T1 = 5559.23 ± 83.51 K and T2 = 3871.64 ± 43.66 K, respectively, and modified Kopal potentials which are a function of primary’s and secondary’s radii Ω1 = 3.436 ± 0.018 and Ω2 = Ocr = 2.980, respectively. It is concluded that ASAS 1725533-1221.4 is found to be near-contact system with almost similar size between primary and secondary components, with its secondary component is already filling its Roche lobe.

New variable stars discovered in the fields of three Galactic open clusters using the VVV survey

This project is a massive near-infrared (NIR) search for variable stars in highly reddened and obscured open cluster (OC) fields projected on regions of the Galactic bulge and disk. The search is performed using photometric NIR data in the J-, H- and Ks- bands obtained from the Vista Variables in the Vía Láctea (VVV) Survey. We performed in each cluster field a variability search using Stetson’s variability statistics to select the variable candidates. Later, those candidates were subjected to a frequency analysis using the Generalized Lomb-Scargle and the Phase Dispersion Minimization algorithms. The number of independent observations range between 63 and 73. The newly discovered variables in this study, 157 in total in three different known OCs, are classified based on their light curve shapes, periods, amplitudes and their location in the corresponding color-magnitude (J−Ks,Ks) and color-color (H−Ks,J−H) diagrams. We found 5 possible Cepheid stars which, based on the period-luminosity relation, are very likely type II Cepheids located behind the bulge. Among the newly discovered variables, there are eclipsing binaries, δ Scuti, as well as background RR Lyrae stars. Using the new version of the Wilson & Devinney code as well as the “Physics Of Eclipsing Binaries” (PHOEBE) code, we analyzed some of the best eclipsing binaries we discovered. Our results show that these studied systems turn out to be ranging from detached to double-contact binaries, with low eccentricities and high inclinations of approximately 80°. Their surface temperatures range between 3500 K and 8000 K.

A Computational Guide to Physics of Eclipsing Binaries. I. Demonstrations and Perspectives

PHOEBE (PHysics Of Eclipsing BinariEs) is a modeling package for eclipsing binary stars, built on top of the widely used WD program of Wilson & Devinney. This introductory paper gives an overview of the most important scientific extensions (incorporating observational spectra of eclipsing binaries into the solution-seeking process, extracting individual temperatures from observed color indices, main-sequence constraining, and proper treatment of the reddening), numerical innovations (suggested improvements to WD's differential corrections method, the new Nelder & Mead downhill simplex method), and technical aspects (back-end scripter structure, graphical user interface). While PHOEBE retains 100% WD compatibility, its add-ons are a powerful way to enhance WD by encompassing even more physics and solution reliability. The operability of all these extensions is demonstrated on a synthetic main-sequence test binary; applications to real data will be published in follow-up papers. PHOEBE is released under the GNU General Public License, which guarantees it to be free and open to anyone interested in joining in on future development.