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CCD photometric light curves of TY UMa in the BVR I c c bands obtained using the 1.0 m telescope at Weihai Observatory of Shandong University. Different symbols represent different days.
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TY UMa is an F-type eclipsing binary star. Four-color light curves and radial velocities of this system were presented and simultaneously analyzed using the W─D code. It is found that TY UMa is a W-subtype shallow contact binary system (f=13.4%) with a mass ratio of q = 2.523. In order to explain the asymmetric light curve of this binary, a dark sp...
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We present BVRI light curves with complete phase coverage for the short-period (p=0.377day) eclipsing binary star GR Boo. We carried out the observations using the SARA 90-cm telescope located at Kitt Peak National Observatory. We obtained six new light curve minimum times. By fitting all of the available O-C minimum times, we obtained an updated e...
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... These systems commonly fill or overfill their Roche lobes and share a common convective envelope. This can lead to mass transfer, energy exchange, and loss of mass and angular momentum from the binary system [3,4]. Various physical processes occur, including the O'Connell effect [5] which is described by asymmetry in the two maxima of the light curve. ...
In this study, we present a detailed photometric analysis of two short-period eclipsing binary systems, $\textbf{ATO J009.3383+34.2329}$ and $CRTS J004004.7+385531$. The photometric data for our analysis was obtained from the Zwicky Transient Facility (ZTF) catalogue at $gri$ filters and the Transiting Exoplanet Survey Satellite (TESS) database. Based on our analysis, we classify both systems as W Uma-type binaries, with A-subtype. To estimate the physical and geometrical parameters of these systems, we employ the PHEOBE code. This results in two totally eclipsing systems with degree of \textbf{inclination} (i) of around 68 and 88 {$\deg$}, respectively. The $ATO J009.3383+34.2329$ indicates a low mass ratio ($q$) binary with $q$=0.107, while $CRTS J004004.7+385531$ exhibits a moderate $q$ value of 0.545.
A cool spot on the surface of the secondary \textbf{star} of $CRTS J004004.7+385531$ with a 30\% cooler atmosphere of the surrounding surface is detected. This is explained by \textbf{magnetic activity} on the surface of $CRTS J004004.7+385531$. Our findings reveal overcontact fill-out factor $f$ with 54 and 52\% for $ATO J009.3383+34.2329$ and $CRTS J004004.7+385531$, respectively. In addition to the light curve modeling, we calculate new epochs and ephemeris for both binary systems. The absolute parameters for the two systems are estimated. Eventually, the systems' evolutionary status along ZAMS and TAMS are discussed.
... The two stars fill or over-fill their Roche lobes, and there exists a common convective envelope(CCE) (Lucy 1968a(Lucy , 1968b around two components. Due to the existence of a CCE, there may be mass transfer and energy exchange between two components (e.g., Li et al. 2015;Liao et al. 2017;Lee & Park 2018;Li 2018). The mass and angular momentum may also be lost from the binary system (e.g., Vanǹt Veer 1979;Rahunen 1981;van Hamme 1982;Qian 2001aQian , 2001bQian , 2003. ...
The multi-color passband CCD light curves of ASAS J124343+1531.7 and LINEAR 2323566 were first obtained by the 0.84 m Ritchey–Chrétien telescope with follow up observations by the WIYN 0.90 m Cassegrain telescope. The data from the Transiting Exoplanet Survey Satellite of ASAS J124343+1531.7 was also applied for subsequent analysis. By analyzing the data through the W-D program, their mass ratios and fill-out factors were determined as 3.758, 1.438 and 31.8%, 14.9%, respectively. ASAS J124343+1531.7 is a W-subtype median contact binary, while LINEAR 2323566 is a W-subtype shallow contact binary, and the asymmetric light curves prove that they both have the O’Connell effect, which is generally explained by magnetic activity. The equivalent widths of H α lines were calculated, which show they certainly have magnetic activity. Moreover, LINEAR 2323566 has a stronger magnetic activity. The analysis of orbital period changes shows that ASAS J124343+1531.7 has a trend of secular period increase, which is generally explained by the mass transfer from the less massive to the more massive star. According to the estimated absolute parameters, their evolutionary states are discussed. The two components of ASAS J124343+1531.7 are both main sequence stars. While for LINEAR 2323566, the more massive star is a main sequence star, the less massive star has evolved out of main sequence and is over-luminous and over-sized.
... It is possible that the third bodies orbiting around this type of binaries may play an important role for their formation and evolution (e.g. Pribulla & Rucinski 2006;D'Angelo, van Kerkwijk& Rucinski 2006;Eggleton & Kisseleva-Eggleton 2008;Eggleton 2012, Zhu et al. 2011, 2013Li et al. 2014aLi et al. , 2015. On the other hand, they may be formed from short-period cool detached binaries through the combination of several physical processes (e.g. ...
Four sets of complete multicolour light curves of the short-period solar-type eclipsing binary V1005 Her are presented. It is found that the depth of the primary minima in the light curves went deeper from 2013 to 2018, and then became shallower again in 2019, while those of the secondary minima were unchanged. The total-eclipse characteristics in the light curves enable us to determine reliable photometric solutions of this system. Our results from the detailed light-curve analysis show that V1005 Her is a W-type shallow-contact binary with spot activities. We have monitored this system for 7 yr and 22 new times of light minimum have been determined. Together with those collected from the literature, we investigate its Observed-Calculated O–C curve and detect a cyclic variation. Because of the insufficient energy, this cyclic change cannot be explained by magnetic activity cycles of the components even if it has high spots activities. The detected cyclic variation is more plausible as the results of the light-time effect due to the existence of a third body orbiting around the central binary. The minimal mass of the additional stellar companion is determined around 0.45 M⊙ in both circular orbit and eccentric orbit cases when a total mass of 1.2 M⊙ for the binary is adopted. This mass is larger than that of the less massive component of the central binary. It implies that the secondary body was not replaced by the third body during early stellar interactions, suggesting that it is a fossil system and keeps original dynamical information.
... Tokovinin et al. (2006) conclude that 96 per cent of binaries with periods shorter than 3 d have tertiary components, based on a survey of 165 solartype spectroscopic binaries. What is more, some contact binaries even have close-in companions with distance less than 3 au , and contact binaries with more than one companions were also reported (Zhu et al. 2013;Li et al. 2015). All of these hierarchical contact binaries are very important samples for investigating the dynamic interactions among multistellar systems. ...
V752 Cen is a triple-lined spectroscopic contact binary. Its multi-colour light curves were obtained in the years 1971 and 2018, independently. Photometric analyses reveal that the two sets of light curves produce almost consistent results. It contains a W-subtype totally eclipsing binary, and its mass ratio and fill-out factor are q = 3.35(1) and $f = 29(2)\, {{\ \rm per\ cent}}$. The absolute elements of its two component stars were determined to be M1 = 0.39(2)M⊙, M2 = 1.31(7)M⊙, R1 = 0.77(1)R⊙, R2 = 1.30(2)R⊙, L1 = 0.75(3)L⊙ and L2 = 2.00(7)L⊙. The period of V752 Cen is 0.37023198 day. The 0.37-d period remained constant from its first measurement in 1971 until the year 2000. However, it changed suddenly around the year 2000 and has been increasing continuously at a rate of dP/dt = +5.05 × 10−7day · year−1 since then, which can be explained by mass transfer from the less massive component star to the more massive one with a rate of $\frac{dM_{2}}{dt}=2.52\times {10^{-7}}M_\odot /year$. The period variation of V752 Cen over the 48 years in which the period has been monitored is really unusual, and is potentially related to effects from the possible presence of a nearby third star or of a pair of stars in a second binary.
... After one month, new CCD observations of the system were taken with the Weihai Observatory 1.0-m telescope of Shandong University (WHOT). Observations in R c I c -bands were carried out on 2017 April 28 by using the PIXIS 2048B CCD camera (Hu et al. 2014;Li et al. 2015). The integration time was 50 s for the I c -band, 70 s for R c -band. ...
W UMa-type binary stars have an apparent short-period cutoff around 0.2 days. Close binaries with orbital periods shorter than this limit are very useful for understanding the formation and evolution of this type of binaries. 2MASS J11553339+3544399 (hereafter J1155) is a red-dwarf binary with a period of 0.199724 days. Multicolor (V, R, R c , I, I c , W) light curves (LCs) for the ultrashort-period eclipsing binary (EB) J1155 are presented and analyzed by using the Wilson-Devinney (W-D) code. We find that J1155 belongs to a rare group of detached red-dwarf EB with periods below the period limit of contact binaries (the other two are BW03 V38 and GSC 2314-0530). It has a high-mass ratio of 0.90. The primary component (the more massive and hotter star) is filling 90% of the critical Roche lobe, while the secondary one is filling about 84.8%. The masses and radii of the two components are estimated as M 1 = 0.475 ± 0.035 M ⊙, M 2 = 0.441 ± 0.044 M ⊙, R 1 = 0.516 ± 0.089 R ⊙, and R 2 = 0.491 ± 0.105 R ⊙, respectively. By analyzing all available times of light minimum, the orbital period changes of the binary system are investigated for the first time. We find that the (O − C) (observed-calculated) diagram shows a cyclic oscillation with an amplitude of 0.00326 days and a period about 9.84 years. This oscillation is explained as the light-travel time effect (LTTE) via the presence of a third body. The mass of the third component in the triple system is computed to be M 3 sin (i') ~ 0.127 M ⊙. The orbital distance between the central binary and the tertiary component is about 4.0 au. It is possible that the third body and the magnetic braking may play important roles in the formation and evolution of J1155 by drawing angular momentum from the central system.
... By using a least-squares method, the new ephemeris was determined: According to Equation (2), the semi-amplitude of cyclic oscillation is 0.0072 days and the sinusoidal term suggests an oscillation period of 3.62 years. The quadratic term in Equation (2) also reveals a continuous period increase at a Li et al. 2014Li et al. , 2015. After the long-term period change is subtracted from the O−C diagram, the cyclic oscillation is shown in the middle panel of Figure 4. ...
TY Pup is a well-known bright eclipsing binary with an orbital period of 0.8192 days. New light curves in B, V, (RI)C bands were obtained with the 0.61 m reflector robotic telescope (PROMPT-8) at CTIO in Chile during 2015 and 2017. By analyzing those photometric data with the W-D method, it is found that TY Pup is a low-mass-ratio (q ∼ 0.184) and deep-contact binary with a high fill-out factor (84.3%). An investigation of all available times of minimum light including three new ones obtained with the 60 cm and the 1.0 m telescopes at Yunnan Observatories in China indicates that the period change of TY Pup is complex. An upward parabolic variation in the O - C diagram is detected to be superimposed on a cyclic oscillation. The upward parabolic change reveals a long-term continuous increase in the orbital period at a rate of dP/dt = 5.57(±0.08) ×10⁻⁸ days yr⁻¹. The period increase can be explained by mass transfer from the less massive component (M 2 ∼ 0.3 M o) to the more massive one (M 1 ∼ 1.65 M o). The binary will be merging when it meets the criterion that the orbital angular momentum is less than three times the total spin angular momentum, i.e., J orb < 3J rot. This suggests that the system will finally merge into a rapid-rotating single star and may produce a luminous red nova. The cyclic oscillation in the O - C diagram can be interpreted by the light-travel time effect via the presence of a third body. © 2018. The American Astronomical Society. All rights reserved.
We firstly studied the neglected totally eclipsing contact binary NSVS 2536063 using the newly observed g′r′i′ light curves of 60 cm Ningbo Bureau of Education and Xinjiang Observatory Telescope (NEXT) and some public data, which come from the Transiting Exoplanet Survey Satellite (TESS), the All-Sky Automated Survey for SuperNovae (ASAS-SN), the Zwicky Transient Facility (ZTF) survey, and the Large sky Area Multi-Object fiber Spectroscopic Telescope (LAMOST). NSVS 2536063 is determined as an A-type median contact binary with a mass ratio of q=0.308 ± 0.001 and the contact degree of f=26 ± 2%. The absolute parameters of the two components were calculated using the photometric parameters and Gaia distance. Then the diagrams of mass–radius and mass-luminosity indicate that the more massive star is a main sequence star and the less massive star is over-sized and over-luminous. Both the hot spot added on the primary star and magnetic emission lines of spectra indicate the possible magnetic activity of NSVS 2536063. The orbital period of NSVS 2536063 may be long-term increasing with a rate of dp/dt = 1.24(±0.19)×10⁻⁷d yr⁻¹, which is often explained by the mass transfer from the less massive star to the more massive one. Mass transfer may also be responsible for the hot spot on the primary star.
The first photometric solution in the B, V, Rc and Ic filters of the short period V1833 Ori eclipsing binary is presented based on new ground-based CCD photometric observations. We analysed the BVRI photometric light curves of the system, using Phoebe0.31a, a binary star modelling program, with the Wilson and Devinney method based on Roche geometry to achieve the best accordance to the photometric observations to determine their absolute parameters from the light curves. We updated the ephemeris of V1833 Ori using two new light curve minima derived by our new observational data from those collected in the literature and analysed the change of the system’s orbital period. The O–C analysis indicates that the variations of the orbital period of V1833 Ori with time are increasing at a rate of 3.03 × 10 ⁻⁷ days yr ⁻¹ . The distance of V1833 Ori are 173.7 ± 15.6 pc. From the solutions, we find that V1833 Ori is A–subtype W UMa over-contact binaries with q = 0.701 mass ratios and f = 1.14 fill–out factor. The HR diagram positions of the eclipsing binary system’s components are discussed. The system’s absolute dimensions were compared to those of similar binaries in the logT ef f − logL, logM − logL, logM − logR and logM − logJ 0 diagrams.
High precision CCD observations of six totally eclipsing contact binaries were presented and analyzed. It is found that only one target is an A-type contact binary (V429 Cam), while the others are W-type contact ones. By analyzing the times of light minima, we discovered that two of them exhibit secular period increase while three manifest long-term period decrease. For V1033 Her, a cyclic variation superimposed on the long-term increase was discovered. By comparing the Gaia distances with those calculated by the absolute parameters of 173 contact binaries, we found that the Gaia distance can be applied to estimate the absolute parameters for most contact binaries. The absolute parameters of our six targets were estimated using their Gaia distances. The evolutionary status of contact binaries was studied, and we found that the A- and W-subtype contact binaries may have different formation channels. The relationship between the spectroscopic and photometric mass ratios for 101 contact binaries was presented. It was discovered that the photometric mass ratios are in good agreement with the spectroscopic ones for almost all of the totally eclipsing systems, which is corresponding to the results derived by Pribulla et al. and Terrell & Wilson.
