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Periodic Variation Studies of the Two Short Period W UMa-type Eclipsing Binaries: LX Lyn and V0853 Aur
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作者 Xu Zhang Bin Zhang 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2024年第1期273-284,共12页
In this paper,new light curves(LCs) of contact eclipsing binary(CEB) systems LX Lyn and V0853 Aur are presented and analyzed by using the 2015 version of the Wilson-Devinney(W-D) code.In order to explain their asymmet... In this paper,new light curves(LCs) of contact eclipsing binary(CEB) systems LX Lyn and V0853 Aur are presented and analyzed by using the 2015 version of the Wilson-Devinney(W-D) code.In order to explain their asymmetric LCs,cool starspots on the components were employed.It is suggested that their fill-out degrees are f=12.0%(LX Lyn) and f=26.3%(V0853 Aur).At the same time,we found that LX Lyn is a W-type eclipsing binary(EB) with an orbital inclination of i=84°.88 and a mass ratio of q=2.31.V0853 Aur is also a W-type CEB with a mass ratio of q=2.77 and an orbital inclination of i= 79°.26.Based on all available times of light minimum,their orbital period changes are studied by using the O-C method.The O-C diagram of LX Lyn reveals a cyclic oscillation with a period of about 14.84 yr and an amplitude of 0.0019 days,which can be explained by the light-travel time effect(LTTE) due to the presence of a third body with a minimum mass of0.06M_⊙.For V0853 Aur,it is discovered that the O-C diagram of the system also shows a cyclic oscillation with a period of 9.64 yr and an amplitude of 0.03365 days.The cyclic oscillation of V0853 Aur can be attributed to the LTTE by means of a third body with a mass no less than 3.77M_⊙.The third body may play an important role in the formation and evolution of these systems. 展开更多
关键词 stars:activity (stars:)binaries(including multiple):close (stars:)binaries:eclipsing (stars:)brown dwarfs stars:evolution stars:formation
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Physical properties and catalog of EW-type eclipsing binaries observed byLAMOST 被引量:10
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作者 Sheng-Bang Qian Jia-Jia He +4 位作者 Jia Zhang Li-Ying Zhu Xiang-Dong Shi Er-Gang Zhao Xiao Zhou 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2017年第8期109-122,共14页
EW-type eclipsing binaries(hereafter called EWs)are strong interacting systems in which both component stars usually fill their critical Roche lobes and share a common envelope.Numerous EWs were discovered by several ... EW-type eclipsing binaries(hereafter called EWs)are strong interacting systems in which both component stars usually fill their critical Roche lobes and share a common envelope.Numerous EWs were discovered by several deep photometric surveys and there were about 40 785 EW-type binary systems listed in the international variable star index(VSX)by 2017 March 13.7938 of them were observed with LAMOST by 2016 November 30 and their spectral types were identified.Stellar atmospheric parameters of 5363 EW-type binary stars were determined based on good spectroscopic observations.In the paper,those EWs are cataloged and their properties are analyzed.The distributions of orbital period(P),effective temperature(T),gravitational acceleration(log(g)),metallicity([Fe/H])and radial velocity(RV)are presented for these observed EW-type systems.It is shown that about 80.6% of sample stars have metallicity below zero,indicating that EW-type systems are old stellar populations.This is in agreement with the conclusion that EW binaries are formed from moderately close binaries through angular momentum loss via magnetic braking that takes a few hundred million to a few billion years.The unusually high metallicities of a few percent of EWs may be caused by contamination of material from the evolution of unseen neutron stars or black holes in the systems.The correlations between orbital period and effective temperature,gravitational acceleration and metallicity are presented and their scatters are mainly caused by(i)the presence of third bodies and(ii)sometimes wrongly determined periods.It is shown that some EWs contain evolved component stars and the physical properties of EWs mainly depend on their orbital periods.It is found that extremely short-period EWs may be older than their long-period cousins because they have lower metallicities.This reveals that they have a longer timescale of pre-contact evolution and their formation and evolution are mainly driven by angular momentum loss via magnetic braking. 展开更多
关键词 STARS binaries close—stars binaries spectroscopic—stars binaries eclipsing—stars evolution
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Photometric study of eclipsing binaries in the Large Magellanic Cloud--I.W UMa type binaries in the Large Magellanic Cloud 被引量:1
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作者 Devarapalli Shanti Priya Kandulapati Sriram Pasagada Vivekananda Rao 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2011年第2期175-180,共6页
Eclipsing binaries are among the most important sources of information on stellar parameters like radii,masses,luminosities,etc.We present the analysis of six W UMa systems discovered in the Large Magellanic Cloud usi... Eclipsing binaries are among the most important sources of information on stellar parameters like radii,masses,luminosities,etc.We present the analysis of six W UMa systems discovered in the Large Magellanic Cloud using the Wilson-Devinney method. 展开更多
关键词 binaries eclipsing -- binaries close
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Orbital parameters and period variation studies of the short-period eclipsing binaries FG Sct, VZ Lib and VZ Psc
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作者 Qiang Yue Li-Yun Zhang +3 位作者 Xian-Ming L.Han Hong-Peng Lu Liu Long Yan Yan 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2019年第7期67-86,共20页
We present eight sets of new light curves for binaries FG Sct,VZ Lib and VZ Psc,which are all contact eclipsing binaries with short orbital periods.We carried out our observations from 2016 to 2017 using the 60-cm tel... We present eight sets of new light curves for binaries FG Sct,VZ Lib and VZ Psc,which are all contact eclipsing binaries with short orbital periods.We carried out our observations from 2016 to 2017 using the 60-cm telescope administered by National Astronomical Observatories,Chinese Academy of Sciences,the Holcomb Observatory at Butler University and the SARA-CT telescope in Chile.We firstly determined the orbital parameters of FG Sct using the O-C method and obtained photometric solutions utilizing the updated W-D program.We also studied its period variation and discovered that its orbital period is decreasing at a rate of 6.39(±0.24)×10^-8 d yr-1,which was likely caused by mass transfer from the primary component to the secondary component or angular momentum interchange between the two components via magnetic interactions.For VZ Lib and VZ Psc,we simultaneously analyzed their BV RI light curves in conjunction with the published radial velocities.In order to obtain the orbital parameters of VZ Lib,we also analyzed its period variation and revised cyclic change,which could be attributed to either the light-time effect due to a tertiary companion or magnetic activity cycle mechanism.We derived the periods of the tertiary component of VZ Lib to be 48.7(±0.1) yr or magnetic cycle to be 46.9(±1.9) yr.Strong emission lines at Ca II H+K,Hα,Hβ,Hγ and Ca II IRT were detected in the LAMOST spectra of VZ Psc,which imply chromospheric activities in this binary system. 展开更多
关键词 stars:binaries:eclipsing stars:individual (FG Sct VZ Lib VZ Psc) stars:starspot
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A photometric study of two neglected eclipsing binaries
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作者 V.Kudak M.Fedurco +1 位作者 V.Perig S.Parimucha 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2021年第7期192-198,共7页
We present the first BVR photometry,period variation and photometric light curve analysis of two poorly studied eclipsing binaries,V1321 Cyg and CR Tau.Observations were carried out from November 2017 to January 2020 ... We present the first BVR photometry,period variation and photometric light curve analysis of two poorly studied eclipsing binaries,V1321 Cyg and CR Tau.Observations were carried out from November 2017 to January 2020 at the observatory of Uzhhorod National University.Period variations were studied using all available early published as well as our minima times.We used the newly developed ELIS a code for the light curve analysis and determination of photometric parameters for both systems.We found that V1321 Cyg is a close detached eclipsing system with a low photometric mass ratio of q=0.28 which suggests that the binary is a post-mass transfer system.No significant period changes in this system are detected.CR Tau is,on the other hand,a semi-detached system where the secondary component almost fills its Roche lobe.We detected a long-term period increase at a rate of 1.49 × 10^(-7) d yr^(-1),which supports mass transfer from the lower mass secondary component to the more massive primary. 展开更多
关键词 binaries:close binaries:eclipsing stars:individual(V1321 Cyg CR Tau)
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Physical Properties of 29 sdB+dM Eclipsing Binaries in Zwicky Transient Facility
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作者 Min Dai Xiao-Dian Chen +3 位作者 Kun Wang Yang-Ping Luo Shu Wang Li-Cai Deng 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2022年第3期221-245,共25页
The development of large-scale time-domain surveys provides an opportunity to study the physical properties as well as the evolutionary scenario of B-type subdwarfs(sdBs)and M-type dwarfs(dMs).Here,we obtained 33 sdB+... The development of large-scale time-domain surveys provides an opportunity to study the physical properties as well as the evolutionary scenario of B-type subdwarfs(sdBs)and M-type dwarfs(dMs).Here,we obtained 33 sdB+dM eclipsing binaries based on the Zwicky Transient Facility(ZTF)light curves and Gaia Early Data Release3(EDR3)parallaxes.By using the PHOEBE code for light curve analysis,we obtain probability distributions for parameters of 29 sdB+dMs.R1,R2 and i are well determined,and the average uncertainty of mass ratio q is 0.08.Our parameters are in good agreement with previous works if a typical mass of sdB is assumed.Based on parameters of 29 sdB+dMs,we find that both the mass ratio q and the companion’s radius R2 decrease with the shortening of the orbital period.For the three sdB+dMs with orbital periods less than 0.075 days,their companions are all brown dwarfs.The masses and radii of the companions satisfy the mass–radius relation for low-mass stars and brown dwarfs.Companions with radii between 0.12 R_(⊙)and 0.15 R_(⊙)seem to be missing in the observations.As more short-period sdB+dM eclipsing binaries are discovered and classified in the future with ZTF and Gaia,we will have more information to constrain the evolutionary ending of sdB+dMs. 展开更多
关键词 (stars:)binaries:eclipsing stars:evolution (stars:)subdwarfs (stars:)brown dwarfs
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Light Curve Analysis and Period Study of Two Eclipsing Binaries UZ Lyr and BR Cyg
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作者 K.Y.Roobiat R.Pazhouhesh 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2022年第2期135-142,共8页
Two eclipsing binary systems,UZ Lyr and BR Cyg,are semi-detached types whose secondary component fills its Roche lobe.Although radial velocity and light curves of these systems have already been investigated separatel... Two eclipsing binary systems,UZ Lyr and BR Cyg,are semi-detached types whose secondary component fills its Roche lobe.Although radial velocity and light curves of these systems have already been investigated separately,both their radial velocity and light curves are analyzed simultaneously for the first time in the present study.Also,the orbital period changes of these systems are studied.Our results show that the mass transfers between components have negligible effects on the orbital period changes of these systems,but two light travel time effects are the reasons for the periodic behavior of the O-C curve for UZ Lyr.We could not remark more information about orbital period changes for BR Cyg,but we find a new orbital period for it.By radial velocity and light curve analysis,we find a cold spot on the secondary component of BR Cyg.The new geometrical and physical parameters of both systems are obtained and their positions on the H-R diagram are demonstrated. 展开更多
关键词 (stars:)binaries(including multiple):close (stars:)binaries:eclipsing stars:individual(UZ Lyr BR Cyg)
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Photometric investigation of eight ultra-short period eclipsing binaries from OGLE
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作者 Shanti Priya D. Ravi Raja P. +2 位作者 Rukmini J. Raghu Prasad M. Vineet S.Thomas 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2020年第8期113-120,共8页
We performed a detailed photometric analysis of eight ultra-short period eclipsing binaries(USPEBs) using the Wilson-Devinney method. We present the modeled light curves and derived photometric solutions. The USPEBs w... We performed a detailed photometric analysis of eight ultra-short period eclipsing binaries(USPEBs) using the Wilson-Devinney method. We present the modeled light curves and derived photometric solutions. The USPEBs with period(P)≤0.21 d considered in our study belong to W-subtype having shallow contact factor(f)<~20%, high mass ratio(q)>~0.7 and later spectral types. The absolute parameters for these short-period binaries were derived applying empirical relations. We discuss the evolutionary stage of these USPEBs using the mass-radius, color-density and period-color diagrams. The objects showed poor metallicities, and some objects were even found to be existing around fully convective limits. The period distribution of USPEBs exhibited a sharp cut-off at 0.22 d;however, we observed significant deficits for our objects in the literature. We examined the statistics of USPEBs studied to date(in terms of the distribution of period, mass ratio and component temperatures of USPEBs) and observed that a dominant distribution of component temperatures for these USPEBs was towards lower temperatures. 展开更多
关键词 stars:low-mass stars:evolution stars:low-mass binaries:eclipsing binaries:close
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Absolute physical parameters of three poorly studied detached eclipsing binaries
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作者 Dao-Ye Yang Li-Fang Li Quan-Wang Han 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2021年第1期220-228,共9页
The photometric and spectroscopic data for three double-lined detached eclipsing binaries were collected from the photometric and spectral surveys.The light and radial velocity curves of each binary system were simult... The photometric and spectroscopic data for three double-lined detached eclipsing binaries were collected from the photometric and spectral surveys.The light and radial velocity curves of each binary system were simultaneously analyzed using Wilson-Devinney(WD)code,and the absolute physical and orbital parameters of these binaries were derived.The masses of both components of ASASSN-V J063123.82+192341.9 were found to be M1=1.088±0.016 and M20.883±0.016 M⊙;those of ASAS J011416+0426.4 were determined to be M1=0.934±0.046 and M2=0.754±0.043 M⊙;and those of MW Aur were derived to be M1=2.052±0.196 and M21.939±0.193 M⊙.Finally,the evolutionary status of these detached binaries was discussed based on their absolute parameters and the theoretical stellar models. 展开更多
关键词 stars:binaries:eclipsing stars:fundamental parameters stars:evolution stars:individual:ASASSN-V J063123.82+192341.9 ASAS J011416+0426.4 and MW Aur
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The First Photometric Analysis of Two Low Mass Ratio Totally Eclipsing Contact Binaries:TIC 393943031 and TIC 89428764
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作者 Yan-Ke Tang Ya-Ni Guo +2 位作者 Kai Li Ning Gai Zhi-Kai Li 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2022年第3期80-87,共8页
Photometric analysis of the contact binaries TIC 393943031 and TIC 89428764 was carried out using Transiting Exoplanet Survey Satellite and SuperWASP data for the first time.Using the Wilson–Devinney code,we have fou... Photometric analysis of the contact binaries TIC 393943031 and TIC 89428764 was carried out using Transiting Exoplanet Survey Satellite and SuperWASP data for the first time.Using the Wilson–Devinney code,we have found that TIC 393943031 is a low-mass-ratio deep contact binary with a fillout factor of 50.9(±1)%and a mass ratio of q=0.163±0.001.TIC 89428764 is a medium and low-mass-ratio contact binary with a fillout factor of 34.5(±1)%and a mass ratio of q=0.147±0.001.Furthermore,the period study reveals both the stars exhibit continuously increasing periods,the increasing rate is 4.21×10^(−7)day yr^(−1) for TIC 393943031 while 6.36×10^(−7)day yr^(−1) for TIC 89428764.The possible reason is mass transfer from the secondary component to the primary component for both stars.Meanwhile,we discussed their evolutionary phases and orbital angular momenta. 展开更多
关键词 STARS (stars:)binaries:eclipsing stars:low-mass
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New Apsidal Motion in Four Eccentric Eclipsing Binaries:V610 Car,V944 Cep,V2815 Ori and V1260 Tau
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作者 Ahmet Bulut 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2022年第11期69-77,共9页
This paper presents an apsidal motion analysis.The apsidal motion analysis of the eccentric eclipsing binaries V610 Car(P=4.84 days),V944 Cep(P=6.56 days),V2815 Ori(P=2.13 days),and V1260 Tau(P=5.43 days)was performed... This paper presents an apsidal motion analysis.The apsidal motion analysis of the eccentric eclipsing binaries V610 Car(P=4.84 days),V944 Cep(P=6.56 days),V2815 Ori(P=2.13 days),and V1260 Tau(P=5.43 days)was performed using minima times from the O-C Gateway database,ASAS-3,ASAS-SN,and TESS,following Lacy’s approach.The rates of change of periastron longitude were found to be 0.0253±0.0041,0.0347±0.0015,0.0288±0.0010 and0.0294±0°.0079 cycle^(-1),respectively.From the light curve study,the first photometric mass ratio of V944 Cep was found to be q=1.4994±0.0012.A new light curve of V944 Cep was obtained using TESS data.The first absolute dimensions of V944 Cep were M_(1)=1.10±0.01 M_(⊙),M_(2)=1.64±0.02 M_(⊙),R_(1)=2.04±0.37 R_(⊙),R_(2)=3.77±0.67 R_(⊙)for the hotter primary component(T_(1)=4925 K),and M_(1)=1.04±0.01 M_(⊙),M_(2)=1.57±0.02 M_(⊙),R_(1)=2.26±0.36 R_(⊙),R_(2)=3.74±0.59 R_(⊙)for the cooler primary component(T_(1)=4475 K).For V610 Car,V944 Cep,V2815 Ori and V1260 Tau,the apsidal motion periods were found to be 188±26 yr,186±8 yr,73±3 yr and 182±38 yr,respectively.For V944 Cep,the internal structural constants of the component stars log_(k2,obs)=-2.05±0.01 and log_(k2,theo)=-1.83 for hotter primary component and log_(k2,obs)=-1.97±0.01 and log_(k2,theo)=-1.89 for cooler primary component were calculated. 展开更多
关键词 (stars:)binaries:eclipsing stars:fundamental parameters techniques:photometric
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Period variations of Algol-type eclipsing binaries AD And, TW Cas and IV Cas
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作者 Stefan Parimucha Pavol Gajdos +2 位作者 Viktor Kudak Miroslav Fedurco Martin Vanko 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2018年第4期115-122,共8页
We present new analyses of variations in O-C diagrams of three Algol-type eclipsing binary stars:AD And,TW Cas and IV Cas.We have used all published minima times(including visual and photographic)as well as newly d... We present new analyses of variations in O-C diagrams of three Algol-type eclipsing binary stars:AD And,TW Cas and IV Cas.We have used all published minima times(including visual and photographic)as well as newly determined ones from our and Super Wasp observations.We determined orbital parameters of 3^(rd) bodies in the systems with statistically significant errors,using our code based on genetic algorithms and Markov chain Monte Carlo simulations.We confirmed the multiple nature of AD And and the triple-star model of TW Cas,and we proposed a quadruple-star model of IV Cas. 展开更多
关键词 binaries close binaries eclipsing techniques photometric stars individual(AD And TW Cas IV Cas)
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Double-lined M dwarf eclipsing binaries from Catalina Sky Survey and LAMOST
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作者 Chien-Hsiu Lee Chien-Cheng Lin 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2017年第2期29-34,共6页
Eclipsing binaries provide a unique opportunity to determine fundamental stellar properties. In the era of wide-field cameras and all-sky imaging surveys, thousands of eclipsing binaries have been reported through lig... Eclipsing binaries provide a unique opportunity to determine fundamental stellar properties. In the era of wide-field cameras and all-sky imaging surveys, thousands of eclipsing binaries have been reported through light curve classification, yet their basic properties remain unexplored due to the ex- tensive efforts needed to follow them up spectroscopically. In this paper we investigate three M2-M3 type double-lined eclipsing binaries discovered by cross-matching eclipsing binaries from the Catalina Sky Survey with spectroscopically classified M dwarfs from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope survey data release one and two. Because these three M dwarf binaries are faint, we further acquire radial velocity measurements using GMOS on the Gemini North telescope with R ~4000, enabling us to determine the mass and radius of individual stellar components. By jointly fitting the light and radial velocity curves of these systems, we derive the mass and radius of the primary and secondary components of these three systems, in the range between 0.28-0.42 MQ and 0.29-0.67 R, respectively. Future observations with a high resolution spectrograph will help us pin down the uncertainties in their stellar parameters, and render these systems benchmarks to study M dwarfs, providing inputs to improving stellar models in the low mass regime, or establishing an empirical mass-radius relation for M dwarf stars. 展开更多
关键词 (stars) binaries eclipsing
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Photometric investigations on two totally eclipsing contact binaries:V342 UMa and V509 Cam
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作者 Kai Li Qi-Qi Xia +6 位作者 Jin-Zhong Liu Yu Zhang Xing Gao Shao-Ming Hu Di-Fu Guo Xu Chen Yuan Liu 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2019年第10期75-86,共12页
By analyzing two sets of complete BV Rc Ic light curves for V342 UMa and three sets of complete BV Rc Ic light curves for V509 Cam, we determined that the two systems are both W-subtype contact binaries and that V342 ... By analyzing two sets of complete BV Rc Ic light curves for V342 UMa and three sets of complete BV Rc Ic light curves for V509 Cam, we determined that the two systems are both W-subtype contact binaries and that V342 UMa manifests a shallow contact configuration, while V509 Cam exhibits a medium contact configuration. Given that both of them are totally eclipsing binaries, the physical parameters derived only by the photometric light curves are reliable. Meanwhile, the period changes of the two targets were analyzed based on all available eclipsing times. We discovered that V342 UMa shows long-term period decrease with a rate of-1.02(±0.54)× 10^-7 d yr^-1 and that V509 Cam displays long-term period increase with a rate of 3.96(±0.90)× 10^-8 d yr^-1. Both the conservative mass transfer and angular momentum loss via magnetic stellar winds can be used to interpret the long-term period decrease of V342 UMa. The longterm period increase of V509 Cam can be explained by mass transfer from the less massive star to the more massive one. The absolute parameters of the two binaries were estimated according to their Gaia distances and our derived photometric solution results. This method can be extended to other contact binaries without radial velocities but with reliable photometric solutions. Their evolutionary states were investigated and we found that they reveal properties that are identical to other W-subtype contact systems. 展开更多
关键词 STARS binaries close-stars eclipsing-stars individual (V342UMa V509Cam)
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Light curve solutions of six eclipsing binaries at the lower limit of periods for W UMa stars
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作者 Diana P.Kjurkchieva Dinko P.Dimitrov Sunay I.Ibryamov 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2015年第9期1493-1503,共11页
Photometric observations are presented in V and I bands of six eclipsing binaries at the lower limit of the orbital periods for W UMa stars. Three of them are newly discovered eclipsing systems. The light curve soluti... Photometric observations are presented in V and I bands of six eclipsing binaries at the lower limit of the orbital periods for W UMa stars. Three of them are newly discovered eclipsing systems. The light curve solutions reveal that all shortperiod targets are contact or overcontact binaries and six new binaries are added to the family of short-period systems with estimated parameters. Four binaries have com- ponents that are equal in size and a mass ratio near 1. The phase variability shown by the V-I colors of all targets may be explained by lower temperatures on their back surfaces than those on their side surfaces. Five systems exhibit the O'Connell effect that can be modeled by cool spots on the side surfaces of their primary components. The light curves of V1067 Her in 2011 and 2012 are fitted by diametrically opposite spots. Applying the criteria for subdivision of W UMa stars to our targets leads to ambiguous results. 展开更多
关键词 methods: data analysis -- catalogs -- stars: fundamental parameters-- stars: binaries eclipsing individual (1SWASP J173828.46+111150.2 1SWASPJ174310.98+432709.6 V1067 Her NSVS 11534299 NSVS 10971359 NSVS11234970 NSVS 11504202)
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Discovery of four W UMa type eclipsing binaries in the field of open cluster ASCC 5
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作者 Xiang-Song Fang Sheng-Hong Gu +1 位作者 Li-Yun Zhang Qing-Feng Pi 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2013年第9期1052-1062,共11页
We carried out time-series photometric observations in the Re-band of the young, poorly studied open cluster ASCC 5 during November and December, 2012, to search for magnetically active stars, and discovered four ecli... We carried out time-series photometric observations in the Re-band of the young, poorly studied open cluster ASCC 5 during November and December, 2012, to search for magnetically active stars, and discovered four eclipsing binary stars in this field. In order to characterize these four newly discovered binaries, we derived their orbital periods by their times of light minimum, estimated their effective tem- peratures based on their (J - H) colors and analyzed their light curves using the Wilson-Devinney light curve modeling technique. Our analyses reveal that all of them are contact binaries with short orbital periods of less than 0.5 d, with spectral types from late-F to mid-K. Among them, one is a typical A subtype contact binary with a mass ratio around 0.5 and a period of 0.44 d, and one is an H subtype contact binary with a high mass ratio around 0.9 and a short period of about 0.27 d. The other two systems show low amplitudes of light variation (Ant 〈0.11m); their actual photomet- ric mass ratios could not be determined by the light curve modelings, probably due to their attributes of being partially eclipsing stars. A preliminary analysis for these two systems indicates that both of them are likely to be W subtype contact binaries with low orbital inclinations. In addition, both of these two low amplitude variables show asymmetric distorted light curves (e.g., O'Connell effect of ARc --~0.02m) during the observing runs, suggesting the presence of starspots on these two systems. More inter- estingly, the one showing a large case of the O'Connell effect presented a remarkable variation in the shape of the light curve on a time scale of one day, indicating that this star is in a very active state. Therefore, these two stars need spectroscopic observations to precisely determine their parameters, as well as further photometric observations to understand the properties of their magnetic activity, e.g., the evolution of starspots. 展开更多
关键词 stars:binaries close -- stars:binaries eclipsing -- stars: spots
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Long-period eclipsing binaries:towards the true mass-luminosity relation.I.the test sample,observations and data analysis
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作者 Alexei Yu.Kniazev Oleg Yu.Maikov +1 位作者 Ivan Yu.Katkov Leonid N.Berdnikov 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2020年第8期169-176,共8页
The mass-luminosity relation is a fundamental law of astrophysics.We have suggested that the currently used mass-luminosity relation is not correct for the M/M⊙>2.7 range of mass since it was created utilizing dou... The mass-luminosity relation is a fundamental law of astrophysics.We have suggested that the currently used mass-luminosity relation is not correct for the M/M⊙>2.7 range of mass since it was created utilizing double-lined eclipsing binaries,where the components are synchronized and consequently change each other's evolutionary path.To exclude this effect,we have started a project to study longperiod massive eclipsing binaries in order to construct radial velocity curves and determine masses for the components.We outline our project and present the selected test sample together with the first HRS/SALT spectral observations and the software package,FITTING BINARY STARS(FBS),that we developed for the analysis of our spectral data.As the first result,we present the radial velocity curves and best-fit orbital elements for the two components of the FP Car binary system from our test sample. 展开更多
关键词 stars:luminosity function mass function stars:binaries:spectroscopic
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Photometric light curve solutions of three ultra-short period eclipsing binaries
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作者 Francesco Acerbi Raul Michel +2 位作者 Carlo Barani Massimiliano Martignoni Lexter Fox-Machado 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2020年第4期163-170,共8页
We present the results of our study of the eclipsing binary systems CSS J112237.1+395219,LINEAR 1286561 and LINEAR 2602707 based on new CCD B,V,Rcand Iccomplete light curves.The ultra-short period nature of these star... We present the results of our study of the eclipsing binary systems CSS J112237.1+395219,LINEAR 1286561 and LINEAR 2602707 based on new CCD B,V,Rcand Iccomplete light curves.The ultra-short period nature of these stars,as reported by Drake et al.,is confirmed and the system’s periods are revised.The light curves were modeled using the 2003 version of the Wilson-Devinney code.When necessary,cool spots on the surface of the primary component were introduced to account for asymmetries in the light curves.As a result,we found that CSS J112237.1+395219 is a W UMa type contact binary system belonging to W subclass with a mass ratio of q=1.61 and a shallow degree of contact of 14.8%where the primary component is hotter than the secondary one by 500 K.LINEAR 1286561 and LINEAR2602707 are detached binary systems with mass ratios q=3.467 and q=0.987 respectively.These detached systems are low-mass M-type eclipsing binaries with similar temperatures.The marginal contact,fill-out factor and temperature difference between components of CSS J112237.1+395219 suggest that this system may be at a key evolutionary state predicted by thermal relaxation oscillation(TRO)theory.From the estimated absolute parameters,we conclude that our systems share common properties with other ultrashort period binaries. 展开更多
关键词 techniques:photometric stars:variables:Contact BINARY stars:individual:CSS J112237.1+395219 LINEAR 1286561 and LINEAR 2602707
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Period Investigation on Two W UMa Binaries HH UMa and V1175 Her
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作者 Linfeng Chang Liying Zhu Fangbin Meng 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2023年第4期184-193,共10页
HH UMa and V1175 Her are two W UMa contact binary systems whose periods were reported as undergoing secular increase.In this paper,we improved their period analyses with a more extensive database of eclipse timings,fi... HH UMa and V1175 Her are two W UMa contact binary systems whose periods were reported as undergoing secular increase.In this paper,we improved their period analyses with a more extensive database of eclipse timings,finding that both periods show cyclic variation.The cyclic variation could be attributed to a Light Travel Time Effect induced by a third body.Both circular orbit and eccentric orbit cases were considered.For HH UMa,the cyclic variation with a period of around 20 yr has been detected,which may be caused by a third body with the mass larger than 0.23 M_(⊙).However,no parabolic variation was detected in its O−C curve,implying the balance of the mass transfer between the two components and the angular momentum loss from the binary system.As to V1175 Her,a long-term period increase superposed on a periodic oscillation was detected.The period increase with a rate of about dP/dt=2×10^(-7)day yr^(−1)indicates the mass transfer from the less massive component to its companion.The cyclic variation of about 7.5 yr could be caused by a hierarchical third body with a minimal mass exceeding 0.46M_(⊙)orbiting around the central binary.This mass is larger than that of the less massive component of the binary,which means that the secondary component was not replaced by the third body during early stellar interactions,implying that it keeps original dynamical information.By removing angular momentum from the central binary system,the tertiary component has played a significant role in the formation of contact binaries. 展开更多
关键词 (stars:)binaries eclipsing-(stars:)binaries(including multiple) close-stars LATE-TYPE
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IP Lyn:A Totally Eclipsing Contact Binary with an Extremely Low Mass Ratio
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作者 Zi-Xuan Yin Zi-Bin Meng +4 位作者 Pei-Ru Wu Xu-Dong Zhang Yun-Xia Yu Ke Hu Fu-Yuan Xiang 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2023年第8期206-219,共14页
We present the first photometric and orbital period investigations for a neglected totally eclipsing contact binary IP Lyn.The photometric solutions derived from both ground-based and several surveys'observations ... We present the first photometric and orbital period investigations for a neglected totally eclipsing contact binary IP Lyn.The photometric solutions derived from both ground-based and several surveys'observations suggest that it is a shallow contact binary with an extremely low mass ratio of 0.055.The weak asymmetry observed in our multiple band light curves can be interpreted as a result of an active cool spot on the primary.The absolute physical parameters were determined with the Gaia-distance-based method and checked by an empirical relation.Combining the eclipse timings collected from the literature and those derived from our and variable surveys'observations,we find that IP Lyn has been undergoing a secular orbital period increase for the past two decades,implying a mass transfer from the less massive secondary to the primary.By comparing the current parameters with the critical instability ones,we infer that IP Lyn is currently stable in spite of its relatively low mass ratio and orbital angular momentum.Finally,from a catalog of 117 extremely low mass ratio contact binaries,we find that their orbital angular momenta are significantly lower than those of the contact binaries with a relatively high mass ratio,suggesting they should be at the late evolutionary stage of a contact binary. 展开更多
关键词 (stars")binaries(including multiple) close-(stars:)binaries eclipsing-stars evolution-stars individual(IP Lyn)
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