Photometric observations of an eclipsing binary system, YY Eridani were done in blue (B) and yellow (V) wavelength bands and, finally, the light curve in each wavelength band was constructed. Orbital elements and phys...Photometric observations of an eclipsing binary system, YY Eridani were done in blue (B) and yellow (V) wavelength bands and, finally, the light curve in each wavelength band was constructed. Orbital elements and physical properties of YY Eridani have been calculated using observational data of Binnendijk (1965) and authors have developed Wilson Devinney technique in analyzing the best solution of this eclipsing binary system. More physical parameters eg: orbital inclination, gravity darkening exponent, effective temperature, gravitational potential etc. of each component were calculated in this research for the best solution of YY Eridani. Synthetic light curves which were constructed from the best solution are in good correspondence with observational light curves of Binnendijk. When comparing with observational light curves obtained from this research, it was found that there exist the phase shift of 0 1. It is possible that physical properties of YY Eridani have been changed due to the rotation of its major axis or mass transfer mechanism of the system.展开更多
We present a time-series BV CCD photometry for an EB-type eclipsing binary NSVS 1908107, a member of the young open cluster NGC 869. The photometric solution was obtained by using the 2003 version of the Wilson-Devinn...We present a time-series BV CCD photometry for an EB-type eclipsing binary NSVS 1908107, a member of the young open cluster NGC 869. The photometric solution was obtained by using the 2003 version of the Wilson-Devinney code. It reveals that the system is a semi-detached binary with the secondary component filling its Roche lobe. The mass ratio was determined to be 0.059±0.001. With the physical parameters of the cluster, the masses, radii and luminosities of the two components of NSVS 1908107 are estimated to be M1 = 10.34±2.29 M⊙, R1 = 4.65re±0.34 Rspectivel⊙, L1 = 8076 y. The results s±371 L = 2.40 how tha⊙and M2 = 0.61 t the secondary co±0.13M⊙, R2±0.17 R⊙, L2 = 1054±48 L⊙mponent could be a giant or subgiant star with the outer envelope being stripped.展开更多
The lander of China’s Chang’E-3 spacecraft is equipped with a 15-cm telescope that is very useful for monitoring celestial objects in the ultraviolet(UV) band(245–340 nm).The Lunar-based Ultraviolet Telescope(LUT) ...The lander of China’s Chang’E-3 spacecraft is equipped with a 15-cm telescope that is very useful for monitoring celestial objects in the ultraviolet(UV) band(245–340 nm).The Lunar-based Ultraviolet Telescope(LUT) is the first long-term lunar-based astronomical observatory,that can make uninterrupted observations of a target from the Moon.Here we present the continuous complete UV light curve of the eclipsing binary TX Herculis(TX Her).The analysis of the light curve suggests that TX Her is a detached binary.The dip in the light curve was explained by the emergence of a stellar dark spot on the less massive F0 type component.The cyclic change of arrival eclipse times for the system reveals that it contains an additional stellar companion with a minimal mass of 0.35 M⊙ and a period of 48.92 yr,which is supported by the detected light contribution of the third body from light curve analysis.This third body may play an important role in the formation of the present short-period system TX Her.展开更多
The LAMOST spectra and Kepler light curves are combined to investigate the detached eclipsing binary KIC 8098300,which shows the O’Connell effect caused by spot/facula modulation.The radial velocity(RV)measurements a...The LAMOST spectra and Kepler light curves are combined to investigate the detached eclipsing binary KIC 8098300,which shows the O’Connell effect caused by spot/facula modulation.The radial velocity(RV)measurements are derived by using the tomographic spectra disentangling technology.The mass ratio q=K1/K2=0.812±0.007,and the orbital semimajor axis a sin i=14.984±0.048 R_(⊙)are obtained by fitting the RV curves.We optimize the binary model concerning the spot/facula activity with the code PHOEBE and obtain precise parameters of the orbit including the eccentricity e=0.0217±0.0008,the inclination i=87°.71±0°.04,and the angle of periastronω=284°.1±0°.5.The masses and radii of the primary and secondary star are determined as M_(1)=1.3467±0.0001 M_(⊙),R_(1)=1.569±0.003 R_(⊙),and M_(2)=1.0940±0.0001 M_(⊙),R_(2)=1.078±0.002 R_(⊙),respectively.The ratio of temperatures of the two component stars is r_(teff)=0.924±0.001.We also obtain the periastron precession speed of 0.000024±0.000001 day cycle-l.The residuals of out-of-eclipse are analyzed using the auto-correlation function and the discrete Fourier transform.The spot/facula activity is relatively weaker,but the lifetime is longer than that of most single main sequence stars in the same temperature range.The average rotation period of the spots P_(rot)=4.32 days is slightly longer than the orbital period,which may be caused by either the migration of spots/faculae along the longitude or the latitudinal differential rotation.The activity may be spot-dominated for the secondary star and facula-dominated for the primary star.The method of this work can be used to analyze more eclipsing binaries with the O’Connell effect in the Kepler field to obtain the precise parameters and investigate the difference of spot behavior between binaries and single stars.It is helpful for a deeper understanding of the stellar magnetic activity and dynamo theory.展开更多
We present CCD photometric observations of an eclipsing binary in the direction of the open cluster Praesepe using the 2 m telescope at IUCAA Girawali Observatory, India. Though the system was classified as an eclipsi...We present CCD photometric observations of an eclipsing binary in the direction of the open cluster Praesepe using the 2 m telescope at IUCAA Girawali Observatory, India. Though the system was classified as an eclipsing binary by Pepper et al., detailed investigations have been lacking. The photometric solutions using the Wilson-Devinney code suggest that it is a W-type W UMa system and, interestingly, the system parameters are similar to another contact binary system SW Lac.展开更多
New multi-color BVRcIc photometric observations are presented for the W UMa type eclips- ing binary V1073 Cyg. The multi-color light curve analysis with the Wilson-Devinney procedure yielded the absolute parameters of...New multi-color BVRcIc photometric observations are presented for the W UMa type eclips- ing binary V1073 Cyg. The multi-color light curve analysis with the Wilson-Devinney procedure yielded the absolute parameters of this system, showing that V 1073 Cyg is a shallow contact binary system with a fill-out factor f = 0.124（±0.011）. We collected all available times of light minima spanning 119yr, including CCD data to construct the O - C curve, and performed detailed O - C analysis. The O - C diagram shows that the period change is complex. A long-term continuous decrease and a cyclic vari- ation exist. The period is decreasing at a rate ofP = -1.04（±0.18） × 10-10 d cycle-land, with the period decrease, V1073 Cyg will evolve to the deep contact stage. The cyclic variation with a period of P3 = 82.7（±3.6） yr and an amplitude of A = 0.028（±0.002） d may be explained by magnetic activ- ity of one or both components or the light travel time effect caused by a distant third companion with M3（i1 = 90°） = 0.511 M⊙.展开更多
The eclipsing binary 2 MASS J04100497+2931023(J04100497+2931023) is classified its spectral type of M0±2 V on basis of a low-resolution spectral survey by the Large Sky Area Multi-Object Fiber Spectroscopic Teles...The eclipsing binary 2 MASS J04100497+2931023(J04100497+2931023) is classified its spectral type of M0±2 V on basis of a low-resolution spectral survey by the Large Sky Area Multi-Object Fiber Spectroscopic Telescope(LAMOST). The low-resolution spectra exhibit strong single-peak emission in the Hα line. We obtained the radial velocities of this binary by means of the Cross-Correlation Function method from the LAMOST medium-resolution spectra. Both components of J04100497+2931023 indicate strong emissions in the Hα line. We performed follow-up photometric observations of J04100497+2931023 using the Xinglong 85 cm telescope of National Astronomical Observatories, Chinese Academy of Sciences. We obtained its full light curve in V RI filters. We first determined their absolute parameters from simultaneously radial velocity and light curves by the Wilson-Devinney program. From our new light curves, we detected three flares for the first time, including one convective flare. The amplitudes,durations, energies, and spectral indices of three flares were also determined. J04100497+2931023 was monitored for approximately 29 h, which indicates that the flare rate is 0.1 flare per hour. We conclude that J04100497+2931023 is a low-mass detached eclipsing binary with strong magnetic activity.展开更多
The new complete BV Rc Ic light curves and spectra of the short-period eclipsing binary XZ CMi are presented.The results from the combined analysis based on the photometric and spectroscopic data show that XZ CMi is a...The new complete BV Rc Ic light curves and spectra of the short-period eclipsing binary XZ CMi are presented.The results from the combined analysis based on the photometric and spectroscopic data show that XZ CMi is a near contact binary with the secondary component filling its critical Roche lobe while the primary filling 91%of its Roche lobe.The investigation of the O-C diagram reveals that its orbital period is continuously increasing,which is consistent with the derived configuration and caused by the mass transfer from the less massive star to the more massive one.In addition,an obvious periodic modulation with the amplitude of0.0187(±0.0016)d and a high eccentric of 0.86(±0.04)is detected,which could be the results of the light time effect as a third star with the mass no less than 0.42(±0.09)M⊙orbiting around the central eclipsing binary once every 95.7(±2.1)yr.Furthermore,we found a visual companion star at 2.4′′east by south of this system at a much greater distance by direct image.The large third light contribution found from the light curve analysis could be well explained by the existence of the third star and the fourth visual one.The similar parallax and proper motion imply that the components of this hierarchical quadruple system might be bounded by gravitation.Spectroscopic observations for two visual components were carried out by the LAMOST and 2.16 m telescopes,respectively.Their different values of[Fe/H]suggest that they were not born from the same origin.Thus,XZ CMi system is an interesting and important target to study the formation of the multiple stars.展开更多
Pulsating stars occupy a significant place in the H-R diagram and it was thought that all stars inside the classical instability strip should pulsate. However, recent studies showed that there are many non-pulsating s...Pulsating stars occupy a significant place in the H-R diagram and it was thought that all stars inside the classical instability strip should pulsate. However, recent studies showed that there are many non-pulsating stars located inside the classical instability strip. The existence of these non-pulsating stars is still a mystery. To deeply understand the properties of these non-pulsating and pulsating stars, one needs precise fundamental stellar parameters(e.g. mass).For this purpose, the eclipsing binaries are unique systems. Hence, in this study, we present the TESS data analysis of one candidate pulsating eclipsing binary system, V948 Her. TESS data were used for the binary modeling with the literature radial velocity measurements, and the precise fundamental parameters of the system were obtained. The system’s age was derived as 1 ± 0.24 Gyr. The positions of the binary components in the H-R diagram were examined and the primary component was found inside the δ Scuti instability strip. However, in the frequency analysis of TESS data, we found no significant pulsation frequencies. Only the harmonics of the orbital periods were obtained in the analysis. Therefore, the system was classified as a non-pulsator. V948 Her is an important object to understand the nature of non-pulsating stars inside the δ Scuti instability strip.展开更多
The existence of pulsating stars in eclipsing binaries has been known for decades.These types of objects are extremely valuable systems for astronomical studies as they exhibit both eclipse and pulsation variations.Th...The existence of pulsating stars in eclipsing binaries has been known for decades.These types of objects are extremely valuable systems for astronomical studies as they exhibit both eclipse and pulsation variations.The eclipsing binaries are the only way to directly measure the mass and radius of stars with a good accuracy(≤1%),while the pulsations are a unique way to probe the stellar interior via oscillation frequencies.There are different types of pulsating stars existing in eclipsing binaries.One of them is theδScuti variables.Currently,the known number ofδScuti stars in eclipsing binaries is around 90 according to the latest catalog of these variables.An increasing number of these kinds of variables is important to understand the stellar structure,evolution and the effect of binarity on the pulsations.Therefore,in this study,we focus on discovering new eclipsing binaries withδScuti component(s).We searched within the northern Transiting Exoplanet Survey Satellite(TESS)field with a visual inspection by following some criteria such as light curve shape,the existence of pulsation like variations in the out-of-eclipse light curve and the T_(eff) values of the targets.As a result of these criteria,we discovered some targets.The orbital variations were first removed from the TESS light curves and frequency analysis was performed on the residuals.The luminosity,and absolute and bolometric magnitudes of the targets were calculated as well.To find how much of these parameters represent the primary(more luminous)binary component,we also computed the flux density ratio of the systems by utilizing the area of the eclipses.In addition,the positions of the systems in the H-R diagram were examined considering the flux density ratios.As a consequence of the investigation,we defined 38 candidateδScuti stars and also one Maia variable in eclipsing binary systems.展开更多
The first BV bands photometric observations and the low-resolution spectrum of the shortest period Am type eclipsing binary TYC 6408-989-1 have been obtained.The stellar atmospheric parameters of the primary star were...The first BV bands photometric observations and the low-resolution spectrum of the shortest period Am type eclipsing binary TYC 6408-989-1 have been obtained.The stellar atmospheric parameters of the primary star were obtained through the spectral fitting as follows:Teff=6990±117 K,log g=4.25±0.26 cm s^(-2),[Fe/H]=-0.45±0.03 dex.The original spectra obtained by European Southern Observatory(ESO)were processed with an IRAF package by us.Based on the ESO blue-violet spectra,TYC 6408-989-1 was concluded as a marginal Am(Am:)star with a spectral type of kA3 hF1 mA5Ⅳ-Ⅴidentified through the MKCLASS program.The observed light curves were analyzed through the WilsonDevinney code.The final photometric solutions show that TYC 6408-989-1 is a marginal contact binary with a low mass ratio(q=0.27).The temperature of the secondary component derived through the light curve analysis is significantly higher than main sequence stars.In addition,TYC 6408-989-1 is a poor thermal contact binary.The temperature differences between the two components is about 1800 K.TYC6408-989-1 should be located in the oscillation stage predicted by the thermal relaxation oscillations theory(TRO)and will evolve into the shallow contact stage eventually.The very short period(less than one day),marginal Am peculiarity and quite large rotational velocity(v sin i■160 km s^(-1))make TYC 6408-989-1 become a challenge to the cut-off of rotation velocities and periods of Am stars.We have collected the well known eclipsing Am binaries with absolute parameters from the literature.展开更多
First multi-wavelength photometric light curves(LCs)of the short-period eclipsing binary(EB)1 SWASP J034439.97+030425.5(hereafter J0344)are presented and analyzed by using the 2013 version of the Wilson-Devinney(W-D)c...First multi-wavelength photometric light curves(LCs)of the short-period eclipsing binary(EB)1 SWASP J034439.97+030425.5(hereafter J0344)are presented and analyzed by using the 2013 version of the Wilson-Devinney(W-D)code.To explain the asymmetric LCs of J0344,a cool star-spot on the less massive component was employed.The photometric solutions suggest that J0344 is a W-subtype shallow contact EB with a contact degree of f=4.9%±3.0%and a mass ratio of q=2.456±0.013.Moreover,an obvious third light was detected in our analysis.We calculated the average luminosity contribution of the third light to the total light,and that value reaches up to 49.78%.Based on the O-C method,the variations of the orbital period were studied for the first time.Our O-C diagram reveals a secular decrease superimposed on a cyclic oscillation.The orbital period decreases at a rate of d P/dt=-6.07×10-7 d yr-1,which can be explained by the mass transfer from the more massive component to the less massive one.Besides,its O-C diagram also shows a cyclic oscillation with an amplitude of 0.0030 d and a period about 7.08 yr,which can be explained by the presence of a third body with a minimum mass of M3 min=0.15±0.02 M⊙.The third component may play an important role in the formation and evolution of J0344 by drawing angular momentum from the central system.展开更多
CCD photometric observations with B and V passbands were performed on the contact binary V3 in the field of open cluster M37. The solutions were obtained for data from both B and V passbands along with R passband give...CCD photometric observations with B and V passbands were performed on the contact binary V3 in the field of open cluster M37. The solutions were obtained for data from both B and V passbands along with R passband given by Hartman et al. using the Wilson-Devinney code. The positive O＇Connell effect was observed in all the three passbands and its associated cool spot parameters were derived. The results indicate that the spot parameters have not shown any significant variability during the last four years. The spot radius was found to be 40° and located close to the equator of the secondary component. The absolute parameters of the system were derived using the empirical relations given by Gazeas et al.展开更多
We present the first evidence for the binarity of four targets in the TESS field.The temperatures are estimated by SED analysis and the orbital periods are determined.The TESS light curves of the systems are analyzed ...We present the first evidence for the binarity of four targets in the TESS field.The temperatures are estimated by SED analysis and the orbital periods are determined.The TESS light curves of the systems are analyzed and the orbital and the absolute parameters are derived.The targets are also compared to wellstudied binary systems with the same morphological type and their evolutionary states are discussed.Our results indicate that the stars belong to the class of eclipsing detached binary systems.展开更多
We present a detailed investigation of the Algol-type binary TZ Lyrae, based on 55 light minimum timings spanning 90 years. It is found that the orbital period shows a long-term increase with a cyclic variation superi...We present a detailed investigation of the Algol-type binary TZ Lyrae, based on 55 light minimum timings spanning 90 years. It is found that the orbital period shows a long-term increase with a cyclic variation superimposed. The rate of the secular increase is dP/dt = ＋7.18 × 10^-8d yr^-1, indicating that a mass transfer from the less massive component to the more massive one at a rate of dra = ＋2.21 × 10^-8M⊙ yr^-1. The cyclic component, with a period of P3 = 45.5 yr and an amplitude of A = 0.^d0040, may be interpreted as either the light-time effect in the presence of a third body or magnetic activity cycles in the components. Using the latest version Wilson-Devinney code, a revised photometric solution was deduced from B and V observations. The results show that TZ Lyr is an Algol-type eclipsing binary with a mass ratio of q = 0.297±0.003）. The semidetached configuration with a lobe-filling secondary suggests a mass transfer from the secondary to the primary, which is in agreement with the long-term period increase of the binary system.展开更多
In 2002,2004 and 2017 we conducted high precision CCD photometry observations of the eclipsing binary system AS Cam.By analysis of the light curves from 1967 to 2017（our data ＋ data from the literature） we obtained...In 2002,2004 and 2017 we conducted high precision CCD photometry observations of the eclipsing binary system AS Cam.By analysis of the light curves from 1967 to 2017（our data ＋ data from the literature） we obtained photometric elements of the system and found a change in the system＇s orbital eccentricity of ？e = 0.03 ± 0.01.This change can indicate that there is a third companion in the system in a highly inclined orbit with respect to the orbital plane of the central binary,and its gravitational influence may cause the discrepancy between observed and theoretical apsidal motion rates of AS Cam.展开更多
CCD photometric observations of the eclipsing binary PS Persei （PS Per） were obtained on two consecutive days in 2009.The 2003 version of the WilsonDevinney code was used to analyze the first complete light curves i...CCD photometric observations of the eclipsing binary PS Persei （PS Per） were obtained on two consecutive days in 2009.The 2003 version of the WilsonDevinney code was used to analyze the first complete light curves in the V and R bands.It is found that PS Per is a short-period Algol-type binary with the less massive component completely filling its inner critical Roche lobe.The mass ratio of q=0.518 and the orbital inclination of i=89.86° are obtained.In addition,based on all available times of primary light minima,including two new ones,the orbital period has been improved.展开更多
We present a comprehensive analysis of BI CVn,an eclipsing overcontact binary system.New BVR photometric observations,combined with available spectroscopic data,were analyzed simultaneously using the Wilson–Devinney ...We present a comprehensive analysis of BI CVn,an eclipsing overcontact binary system.New BVR photometric observations,combined with available spectroscopic data,were analyzed simultaneously using the Wilson–Devinney method to derive the orbital and physical parameters of the system.The resulting stellar parameters are M1=0.58±0.01M⊙,M2=1.42±0.02M⊙,R1=0.88±0.01R⊙,R2=1.31±0.01R⊙,with an orbital separation of a=2.80±0.01R⊙.Based on all available CCD times of minimum light,including both ground-based and T ESS observations,the(O-C)diagram of BI CVn was analyzed.T he orbital period exhibits a long-term decrease at a rate of-2.3239(±0.0001)×10-8 day yr-1,likely due to mass transfer from the more massive to the less massive component.Superimposed on this trend is a cyclic variation with a period of 56.84±0.08 yr,indicative of a light-travel time effect caused by a third body,whose estimated mass is 0.63±0.02M⊙.Using these derived parameters,we modeled the binary’s evolution through non-conservative processes with the Binary Star Evolution code.The evolutionary tracks of the components were examined in multiple parameter planes,leading to an estimated merger timescale of approximately 2.70 Gyr.展开更多
Using ground-based telescopes,the multi-color photometric observations of the contact binary EF Boo were obtained in 2020,2023,and 2024.Combining these with 7-sectors of light curves from TESS data,the variations of t...Using ground-based telescopes,the multi-color photometric observations of the contact binary EF Boo were obtained in 2020,2023,and 2024.Combining these with 7-sectors of light curves from TESS data,the variations of the O'Connell effect in continuous time and shapes of light curves over several years were identified.Three sets of typical light curves were analyzed to determine the photometric solutions via the Wilson-Devinney program.Considering the spectroscopic mass ratio of q=0.53,these photometric solutions suggest that EF Boo is a W-type W UMa contact binary with the averaged filling factor of f=22.26%,a small temperature difference,and a cool spot on the primary component.If the variations of the O'Connell effect are due to the magnetic activity of this cool spot,the longitudinal location varied from 50.4 to 302.7 over the time interval of 1434 days.Based on all CCD minimum times from ground-based telescope and TESS data,the O-C curve was also analyzed.A cyclic oscillation(A3=0.00575 days,T3=27.8 yr)superimposed on a secular increase(dP/dt=6.74×10^(-8)day yr^(-1))was discovered for the first time.The successive increase is possibly a result of mass transfer from the less massive star to the more massive one.The cyclic oscillations were possibly explained by the light-travel time effect via a third body or the magnetic activities.From the short cadence observations from TESS,we also calculated the value of the O'Connell effect and O-C value for each cycle and found no correlation between the O'Connell effect and O-C over nearly 30 days across different sectors.展开更多
To understand the formation mechanism of blue stragglers in open clusters, we conducted a photometric analysis for a blue straggler eclipsing binary in the old open cluster NGC 2141. By using the least square fitting ...To understand the formation mechanism of blue stragglers in open clusters, we conducted a photometric analysis for a blue straggler eclipsing binary in the old open cluster NGC 2141. By using the least square fitting of times of minima, we derived the ephemeris and redetermined the orbital period of this system to be 0.6227 d. We have also done a photometric analysis for light curve with the Wilson-Devinney Code （2003）. The photometric solutions reveal a semi-detached binary with the second- ary component filling its Roche lobe. The photometric mass ratio MJMI （secondary/primary） was determined to be 0.190_＋0.002 and the ratio of V-band luminosity L2/LI（V） is about 0.033_＋0.001, which indicates the secondary component is overluminous. Thus, this blue straggler likely results from a substantial mass exchange between these two components.展开更多
文摘Photometric observations of an eclipsing binary system, YY Eridani were done in blue (B) and yellow (V) wavelength bands and, finally, the light curve in each wavelength band was constructed. Orbital elements and physical properties of YY Eridani have been calculated using observational data of Binnendijk (1965) and authors have developed Wilson Devinney technique in analyzing the best solution of this eclipsing binary system. More physical parameters eg: orbital inclination, gravity darkening exponent, effective temperature, gravitational potential etc. of each component were calculated in this research for the best solution of YY Eridani. Synthetic light curves which were constructed from the best solution are in good correspondence with observational light curves of Binnendijk. When comparing with observational light curves obtained from this research, it was found that there exist the phase shift of 0 1. It is possible that physical properties of YY Eridani have been changed due to the rotation of its major axis or mass transfer mechanism of the system.
基金supported by the National Natural Science Foundation of China(Grant Nos.U1331121,U1231202,11373037 and 11303021)
文摘We present a time-series BV CCD photometry for an EB-type eclipsing binary NSVS 1908107, a member of the young open cluster NGC 869. The photometric solution was obtained by using the 2003 version of the Wilson-Devinney code. It reveals that the system is a semi-detached binary with the secondary component filling its Roche lobe. The mass ratio was determined to be 0.059±0.001. With the physical parameters of the cluster, the masses, radii and luminosities of the two components of NSVS 1908107 are estimated to be M1 = 10.34±2.29 M⊙, R1 = 4.65re±0.34 Rspectivel⊙, L1 = 8076 y. The results s±371 L = 2.40 how tha⊙and M2 = 0.61 t the secondary co±0.13M⊙, R2±0.17 R⊙, L2 = 1054±48 L⊙mponent could be a giant or subgiant star with the outer envelope being stripped.
基金supported by the National Natural Science Foundation of China (Grant Nos. 11573063 and 11611530685)the Key Science Foundation of Yunnan Province (Grant No. 2017FA001)+1 种基金CAS “Light of West China” ProgramCAS Interdisciplinary Innovation Team
文摘The lander of China’s Chang’E-3 spacecraft is equipped with a 15-cm telescope that is very useful for monitoring celestial objects in the ultraviolet(UV) band(245–340 nm).The Lunar-based Ultraviolet Telescope(LUT) is the first long-term lunar-based astronomical observatory,that can make uninterrupted observations of a target from the Moon.Here we present the continuous complete UV light curve of the eclipsing binary TX Herculis(TX Her).The analysis of the light curve suggests that TX Her is a detached binary.The dip in the light curve was explained by the emergence of a stellar dark spot on the less massive F0 type component.The cyclic change of arrival eclipse times for the system reveals that it contains an additional stellar companion with a minimal mass of 0.35 M⊙ and a period of 48.92 yr,which is supported by the detected light contribution of the third body from light curve analysis.This third body may play an important role in the formation of the present short-period system TX Her.
基金the support from the National Natural Science Foundation of China (NSFC) through the grants 11833002, 12090040, and 12090042Guo Shou Jing Telescope (the Large Sky Area Multi-Object Fiber Spectroscopic Telescope LAMOST) is a National Major Scientific Project built by the Chinese Academy of Sciences+2 种基金Funding for the project has been provided by the National Development and Reform CommissionLAMOST is operated and managed by the National Astronomical Observatories, Chinese Academy of SciencesFunding for the Kepler mission is provided by the NASA Science Mission directorate。
文摘The LAMOST spectra and Kepler light curves are combined to investigate the detached eclipsing binary KIC 8098300,which shows the O’Connell effect caused by spot/facula modulation.The radial velocity(RV)measurements are derived by using the tomographic spectra disentangling technology.The mass ratio q=K1/K2=0.812±0.007,and the orbital semimajor axis a sin i=14.984±0.048 R_(⊙)are obtained by fitting the RV curves.We optimize the binary model concerning the spot/facula activity with the code PHOEBE and obtain precise parameters of the orbit including the eccentricity e=0.0217±0.0008,the inclination i=87°.71±0°.04,and the angle of periastronω=284°.1±0°.5.The masses and radii of the primary and secondary star are determined as M_(1)=1.3467±0.0001 M_(⊙),R_(1)=1.569±0.003 R_(⊙),and M_(2)=1.0940±0.0001 M_(⊙),R_(2)=1.078±0.002 R_(⊙),respectively.The ratio of temperatures of the two component stars is r_(teff)=0.924±0.001.We also obtain the periastron precession speed of 0.000024±0.000001 day cycle-l.The residuals of out-of-eclipse are analyzed using the auto-correlation function and the discrete Fourier transform.The spot/facula activity is relatively weaker,but the lifetime is longer than that of most single main sequence stars in the same temperature range.The average rotation period of the spots P_(rot)=4.32 days is slightly longer than the orbital period,which may be caused by either the migration of spots/faculae along the longitude or the latitudinal differential rotation.The activity may be spot-dominated for the secondary star and facula-dominated for the primary star.The method of this work can be used to analyze more eclipsing binaries with the O’Connell effect in the Kepler field to obtain the precise parameters and investigate the difference of spot behavior between binaries and single stars.It is helpful for a deeper understanding of the stellar magnetic activity and dynamo theory.
文摘We present CCD photometric observations of an eclipsing binary in the direction of the open cluster Praesepe using the 2 m telescope at IUCAA Girawali Observatory, India. Though the system was classified as an eclipsing binary by Pepper et al., detailed investigations have been lacking. The photometric solutions using the Wilson-Devinney code suggest that it is a W-type W UMa system and, interestingly, the system parameters are similar to another contact binary system SW Lac.
基金partly supported by the National Natural Science Foundation of China(Nos.11573063,11325315 and U1631108)the Key Science Foundation of Yunnan Province(No.2017FA001)+1 种基金Chinese Academy of Sciences“Light of West China”Programthe research fund of Sichuan University of Science and Engineering(Grant No.2015RC42)
文摘New multi-color BVRcIc photometric observations are presented for the W UMa type eclips- ing binary V1073 Cyg. The multi-color light curve analysis with the Wilson-Devinney procedure yielded the absolute parameters of this system, showing that V 1073 Cyg is a shallow contact binary system with a fill-out factor f = 0.124（±0.011）. We collected all available times of light minima spanning 119yr, including CCD data to construct the O - C curve, and performed detailed O - C analysis. The O - C diagram shows that the period change is complex. A long-term continuous decrease and a cyclic vari- ation exist. The period is decreasing at a rate ofP = -1.04（±0.18） × 10-10 d cycle-land, with the period decrease, V1073 Cyg will evolve to the deep contact stage. The cyclic variation with a period of P3 = 82.7（±3.6） yr and an amplitude of A = 0.028（±0.002） d may be explained by magnetic activ- ity of one or both components or the light travel time effect caused by a distant third companion with M3（i1 = 90°） = 0.511 M⊙.
基金Our research was supported by the Joint Research Fund in Astronomy(Grant Nos.11963002,U1631236 and U1431114)under a cooperative agreement between NSFC and CASWe acknowledge the support of the staff of the Xinglong 85 cm telescope and Cultivation Project for LAMOST Scientific Payoff and Research Achievement of CAMS-CAS.
文摘The eclipsing binary 2 MASS J04100497+2931023(J04100497+2931023) is classified its spectral type of M0±2 V on basis of a low-resolution spectral survey by the Large Sky Area Multi-Object Fiber Spectroscopic Telescope(LAMOST). The low-resolution spectra exhibit strong single-peak emission in the Hα line. We obtained the radial velocities of this binary by means of the Cross-Correlation Function method from the LAMOST medium-resolution spectra. Both components of J04100497+2931023 indicate strong emissions in the Hα line. We performed follow-up photometric observations of J04100497+2931023 using the Xinglong 85 cm telescope of National Astronomical Observatories, Chinese Academy of Sciences. We obtained its full light curve in V RI filters. We first determined their absolute parameters from simultaneously radial velocity and light curves by the Wilson-Devinney program. From our new light curves, we detected three flares for the first time, including one convective flare. The amplitudes,durations, energies, and spectral indices of three flares were also determined. J04100497+2931023 was monitored for approximately 29 h, which indicates that the flare rate is 0.1 flare per hour. We conclude that J04100497+2931023 is a low-mass detached eclipsing binary with strong magnetic activity.
基金the National Natural Science Foundation of China(Grant No.11922306)the Key Science Foundation of Yunnan Province(Grant No.2017FA001)the CAS Interdisciplinary Innovation Team。
文摘The new complete BV Rc Ic light curves and spectra of the short-period eclipsing binary XZ CMi are presented.The results from the combined analysis based on the photometric and spectroscopic data show that XZ CMi is a near contact binary with the secondary component filling its critical Roche lobe while the primary filling 91%of its Roche lobe.The investigation of the O-C diagram reveals that its orbital period is continuously increasing,which is consistent with the derived configuration and caused by the mass transfer from the less massive star to the more massive one.In addition,an obvious periodic modulation with the amplitude of0.0187(±0.0016)d and a high eccentric of 0.86(±0.04)is detected,which could be the results of the light time effect as a third star with the mass no less than 0.42(±0.09)M⊙orbiting around the central eclipsing binary once every 95.7(±2.1)yr.Furthermore,we found a visual companion star at 2.4′′east by south of this system at a much greater distance by direct image.The large third light contribution found from the light curve analysis could be well explained by the existence of the third star and the fourth visual one.The similar parallax and proper motion imply that the components of this hierarchical quadruple system might be bounded by gravitation.Spectroscopic observations for two visual components were carried out by the LAMOST and 2.16 m telescopes,respectively.Their different values of[Fe/H]suggest that they were not born from the same origin.Thus,XZ CMi system is an interesting and important target to study the formation of the multiple stars.
基金supported by the Scientific and Technological Research Council (TUBITAK) project through 120F330Funding for the TESS mission is provided by the NASA Explorer Programnational institutions,in particular the institutions participating in the Gaia Multilateral Agreement。
文摘Pulsating stars occupy a significant place in the H-R diagram and it was thought that all stars inside the classical instability strip should pulsate. However, recent studies showed that there are many non-pulsating stars located inside the classical instability strip. The existence of these non-pulsating stars is still a mystery. To deeply understand the properties of these non-pulsating and pulsating stars, one needs precise fundamental stellar parameters(e.g. mass).For this purpose, the eclipsing binaries are unique systems. Hence, in this study, we present the TESS data analysis of one candidate pulsating eclipsing binary system, V948 Her. TESS data were used for the binary modeling with the literature radial velocity measurements, and the precise fundamental parameters of the system were obtained. The system’s age was derived as 1 ± 0.24 Gyr. The positions of the binary components in the H-R diagram were examined and the primary component was found inside the δ Scuti instability strip. However, in the frequency analysis of TESS data, we found no significant pulsation frequencies. Only the harmonics of the orbital periods were obtained in the analysis. Therefore, the system was classified as a non-pulsator. V948 Her is an important object to understand the nature of non-pulsating stars inside the δ Scuti instability strip.
基金the Scientific and Technological Research Council(TUBITAK)under Grant No.120F330Funding for the TESS mission is provided by the NASA Explorer Program。
文摘The existence of pulsating stars in eclipsing binaries has been known for decades.These types of objects are extremely valuable systems for astronomical studies as they exhibit both eclipse and pulsation variations.The eclipsing binaries are the only way to directly measure the mass and radius of stars with a good accuracy(≤1%),while the pulsations are a unique way to probe the stellar interior via oscillation frequencies.There are different types of pulsating stars existing in eclipsing binaries.One of them is theδScuti variables.Currently,the known number ofδScuti stars in eclipsing binaries is around 90 according to the latest catalog of these variables.An increasing number of these kinds of variables is important to understand the stellar structure,evolution and the effect of binarity on the pulsations.Therefore,in this study,we focus on discovering new eclipsing binaries withδScuti component(s).We searched within the northern Transiting Exoplanet Survey Satellite(TESS)field with a visual inspection by following some criteria such as light curve shape,the existence of pulsation like variations in the out-of-eclipse light curve and the T_(eff) values of the targets.As a result of these criteria,we discovered some targets.The orbital variations were first removed from the TESS light curves and frequency analysis was performed on the residuals.The luminosity,and absolute and bolometric magnitudes of the targets were calculated as well.To find how much of these parameters represent the primary(more luminous)binary component,we also computed the flux density ratio of the systems by utilizing the area of the eclipses.In addition,the positions of the systems in the H-R diagram were examined considering the flux density ratios.As a consequence of the investigation,we defined 38 candidateδScuti stars and also one Maia variable in eclipsing binary systems.
基金partly supported by the National Natural Science Foundation of China(Nos.11922306 and U1831109)the Natural Science Foundation of Shandong Province(Nos.ZR2020QA048)+1 种基金the CAS Interdisciplinary Innovation Teampartially supported by the Open Project Program of the Key Laboratory of Optical Astronomy,National Astronomical Observatories,Chinese Academy of Sciences。
文摘The first BV bands photometric observations and the low-resolution spectrum of the shortest period Am type eclipsing binary TYC 6408-989-1 have been obtained.The stellar atmospheric parameters of the primary star were obtained through the spectral fitting as follows:Teff=6990±117 K,log g=4.25±0.26 cm s^(-2),[Fe/H]=-0.45±0.03 dex.The original spectra obtained by European Southern Observatory(ESO)were processed with an IRAF package by us.Based on the ESO blue-violet spectra,TYC 6408-989-1 was concluded as a marginal Am(Am:)star with a spectral type of kA3 hF1 mA5Ⅳ-Ⅴidentified through the MKCLASS program.The observed light curves were analyzed through the WilsonDevinney code.The final photometric solutions show that TYC 6408-989-1 is a marginal contact binary with a low mass ratio(q=0.27).The temperature of the secondary component derived through the light curve analysis is significantly higher than main sequence stars.In addition,TYC 6408-989-1 is a poor thermal contact binary.The temperature differences between the two components is about 1800 K.TYC6408-989-1 should be located in the oscillation stage predicted by the thermal relaxation oscillations theory(TRO)and will evolve into the shallow contact stage eventually.The very short period(less than one day),marginal Am peculiarity and quite large rotational velocity(v sin i■160 km s^(-1))make TYC 6408-989-1 become a challenge to the cut-off of rotation velocities and periods of Am stars.We have collected the well known eclipsing Am binaries with absolute parameters from the literature.
基金supported by the Natural Natural Science Foundation of China(NSFC)(Grant Nos.U1931101,11933008,11573063,U1731238,U1831120 and 11565010)the Key Science Foundation of Yunnan Province(No.2017FA001)+7 种基金the Special Funds for Theoretical Physics of the NSFC(No.11847102)the Joint Research Fund in Astronomy(Grant Nos.U1631108 and U1831109)under cooperative agreement between the NSFC and the Chinese Academy of Sciences(CAS)the research fund of Sichuan University of Science and Engineering(Grant No.2015RC42)the Science Foundation of China University of Petroleum-Beijing At Karamay(No.RCYJ2016B-03-006)the Key Laboratory for the Structure and Evolution of Celestial Objects,CAS(No.OP201708)the Doctoral Starting up Foundation of Guizhou Normal University 2018(GZNUD[2018]12)the Guizhou province’s innovation and entrepreneurial project for high-level overseas talents(Grant No.[2019]02)supported by the Open Project Program of the Key Laboratory of Optical Astronomy,National Astronomical Observatories,Chinese Academy of Sciences。
文摘First multi-wavelength photometric light curves(LCs)of the short-period eclipsing binary(EB)1 SWASP J034439.97+030425.5(hereafter J0344)are presented and analyzed by using the 2013 version of the Wilson-Devinney(W-D)code.To explain the asymmetric LCs of J0344,a cool star-spot on the less massive component was employed.The photometric solutions suggest that J0344 is a W-subtype shallow contact EB with a contact degree of f=4.9%±3.0%and a mass ratio of q=2.456±0.013.Moreover,an obvious third light was detected in our analysis.We calculated the average luminosity contribution of the third light to the total light,and that value reaches up to 49.78%.Based on the O-C method,the variations of the orbital period were studied for the first time.Our O-C diagram reveals a secular decrease superimposed on a cyclic oscillation.The orbital period decreases at a rate of d P/dt=-6.07×10-7 d yr-1,which can be explained by the mass transfer from the more massive component to the less massive one.Besides,its O-C diagram also shows a cyclic oscillation with an amplitude of 0.0030 d and a period about 7.08 yr,which can be explained by the presence of a third body with a minimum mass of M3 min=0.15±0.02 M⊙.The third component may play an important role in the formation and evolution of J0344 by drawing angular momentum from the central system.
文摘CCD photometric observations with B and V passbands were performed on the contact binary V3 in the field of open cluster M37. The solutions were obtained for data from both B and V passbands along with R passband given by Hartman et al. using the Wilson-Devinney code. The positive O＇Connell effect was observed in all the three passbands and its associated cool spot parameters were derived. The results indicate that the spot parameters have not shown any significant variability during the last four years. The spot radius was found to be 40° and located close to the equator of the secondary component. The absolute parameters of the system were derived using the empirical relations given by Gazeas et al.
基金the TESS mission is provided by NASA’s Science Mission DirectorateSupport for MAST for non-HST data is provided by the NASA Office of Space Science via grant NNX13AC07G and by other grants and contracts+1 种基金This publication makes use of VOSA,developed under the Spanish Virtual Observatory project supported by the Spanish MINECO through grant AyA2017–84089VOSA has been partially updated by using funding from the European Union’s Horizon 2020 Research and Innovation Programme,under Grant Agreement No.776403(EXOPLANETS-A)。
文摘We present the first evidence for the binarity of four targets in the TESS field.The temperatures are estimated by SED analysis and the orbital periods are determined.The TESS light curves of the systems are analyzed and the orbital and the absolute parameters are derived.The targets are also compared to wellstudied binary systems with the same morphological type and their evolutionary states are discussed.Our results indicate that the stars belong to the class of eclipsing detached binary systems.
文摘We present a detailed investigation of the Algol-type binary TZ Lyrae, based on 55 light minimum timings spanning 90 years. It is found that the orbital period shows a long-term increase with a cyclic variation superimposed. The rate of the secular increase is dP/dt = ＋7.18 × 10^-8d yr^-1, indicating that a mass transfer from the less massive component to the more massive one at a rate of dra = ＋2.21 × 10^-8M⊙ yr^-1. The cyclic component, with a period of P3 = 45.5 yr and an amplitude of A = 0.^d0040, may be interpreted as either the light-time effect in the presence of a third body or magnetic activity cycles in the components. Using the latest version Wilson-Devinney code, a revised photometric solution was deduced from B and V observations. The results show that TZ Lyr is an Algol-type eclipsing binary with a mass ratio of q = 0.297±0.003）. The semidetached configuration with a lobe-filling secondary suggests a mass transfer from the secondary to the primary, which is in agreement with the long-term period increase of the binary system.
基金supported by the funding program BR05236322 of the Ministry of Education and Science RKa grant for Leading Scientific Schools NSh-9670.2016.2(Russia)
文摘In 2002,2004 and 2017 we conducted high precision CCD photometry observations of the eclipsing binary system AS Cam.By analysis of the light curves from 1967 to 2017（our data ＋ data from the literature） we obtained photometric elements of the system and found a change in the system＇s orbital eccentricity of ？e = 0.03 ± 0.01.This change can indicate that there is a third companion in the system in a highly inclined orbit with respect to the orbital plane of the central binary,and its gravitational influence may cause the discrepancy between observed and theoretical apsidal motion rates of AS Cam.
基金supported by the Natural Science Foundation of Shanxi Normal University (No.ZR09002)
文摘CCD photometric observations of the eclipsing binary PS Persei （PS Per） were obtained on two consecutive days in 2009.The 2003 version of the WilsonDevinney code was used to analyze the first complete light curves in the V and R bands.It is found that PS Per is a short-period Algol-type binary with the less massive component completely filling its inner critical Roche lobe.The mass ratio of q=0.518 and the orbital inclination of i=89.86° are obtained.In addition,based on all available times of primary light minima,including two new ones,the orbital period has been improved.
基金a project supported by the Scientific and Technological Research Council of Türkiye (TüB?TAK) under grant No.114F166
文摘We present a comprehensive analysis of BI CVn,an eclipsing overcontact binary system.New BVR photometric observations,combined with available spectroscopic data,were analyzed simultaneously using the Wilson–Devinney method to derive the orbital and physical parameters of the system.The resulting stellar parameters are M1=0.58±0.01M⊙,M2=1.42±0.02M⊙,R1=0.88±0.01R⊙,R2=1.31±0.01R⊙,with an orbital separation of a=2.80±0.01R⊙.Based on all available CCD times of minimum light,including both ground-based and T ESS observations,the(O-C)diagram of BI CVn was analyzed.T he orbital period exhibits a long-term decrease at a rate of-2.3239(±0.0001)×10-8 day yr-1,likely due to mass transfer from the more massive to the less massive component.Superimposed on this trend is a cyclic variation with a period of 56.84±0.08 yr,indicative of a light-travel time effect caused by a third body,whose estimated mass is 0.63±0.02M⊙.Using these derived parameters,we modeled the binary’s evolution through non-conservative processes with the Binary Star Evolution code.The evolutionary tracks of the components were examined in multiple parameter planes,leading to an estimated merger timescale of approximately 2.70 Gyr.
基金support of the staff of the 85 cm,60 cm telescopes at the Xinglong observational station of the National Astronomical Observatories,Chinese Academy of Sciences,and TESS team works funding by the NASA Science Mission directorate.This work is sponsored by the Natural Science Foundation of Xinjiang Uygur Autonomous Region(No.2022D01A164)the National Natural Science Foundation of China(Nos.U1831109 and 12103030)。
文摘Using ground-based telescopes,the multi-color photometric observations of the contact binary EF Boo were obtained in 2020,2023,and 2024.Combining these with 7-sectors of light curves from TESS data,the variations of the O'Connell effect in continuous time and shapes of light curves over several years were identified.Three sets of typical light curves were analyzed to determine the photometric solutions via the Wilson-Devinney program.Considering the spectroscopic mass ratio of q=0.53,these photometric solutions suggest that EF Boo is a W-type W UMa contact binary with the averaged filling factor of f=22.26%,a small temperature difference,and a cool spot on the primary component.If the variations of the O'Connell effect are due to the magnetic activity of this cool spot,the longitudinal location varied from 50.4 to 302.7 over the time interval of 1434 days.Based on all CCD minimum times from ground-based telescope and TESS data,the O-C curve was also analyzed.A cyclic oscillation(A3=0.00575 days,T3=27.8 yr)superimposed on a secular increase(dP/dt=6.74×10^(-8)day yr^(-1))was discovered for the first time.The successive increase is possibly a result of mass transfer from the less massive star to the more massive one.The cyclic oscillations were possibly explained by the light-travel time effect via a third body or the magnetic activities.From the short cadence observations from TESS,we also calculated the value of the O'Connell effect and O-C value for each cycle and found no correlation between the O'Connell effect and O-C over nearly 30 days across different sectors.
基金supported by the National Natural Science Foundation of China (Grant Nos. 11033008 and 11103072)the Chinese Academy of Sciences (Grant No. KJCX2-YW-T24)the National Basic Research Program of China (Grant No. 2009CB824800)
文摘To understand the formation mechanism of blue stragglers in open clusters, we conducted a photometric analysis for a blue straggler eclipsing binary in the old open cluster NGC 2141. By using the least square fitting of times of minima, we derived the ephemeris and redetermined the orbital period of this system to be 0.6227 d. We have also done a photometric analysis for light curve with the Wilson-Devinney Code （2003）. The photometric solutions reveal a semi-detached binary with the second- ary component filling its Roche lobe. The photometric mass ratio MJMI （secondary/primary） was determined to be 0.190_＋0.002 and the ratio of V-band luminosity L2/LI（V） is about 0.033_＋0.001, which indicates the secondary component is overluminous. Thus, this blue straggler likely results from a substantial mass exchange between these two components.
