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A new photometric study of the triple star system EF Draconis

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Research in Astronomy and Astrophysics 2012年第4期12卷 419-432页

作者： yuan-gui yang School of Physics and Electronic Information Huaibei Normal UniversityHuaibei 235000China Key Laboratory of the Structure and Evolution of Celestial Objects Chinese Academy of SciencesKunming 650011China

We present new charge-coupled device （CCD） photometry for the triple star EF Draconis, obtained in 2009 and 2011. Using the updated Wilson-Devinney program, the photometric solutions were deduced from two sets of light curves. The results indicate that EF Dra is an A-type W UMa binary with a contact degree of f = 46.7%（ ± 0.6%） and a third light of l 3 ■1.5%. Through analyzing the O C curve, it is found that the orbital period shows a long-time increase with a lighttime orbit. The period, semi-amplitude and eccentricity of the third body are P mod = 17.20（ ± 0.18） yr, A = 0.0039 d （ ± 0.0002 d ） and e = 0.49（ ± 0.02） respectively. This kind of tertiary companion may extract angular momentum from the central system. The orbital period of EF Dra secularly increases at a rate of dP/dt = ＋3.72（ ± 0.07） × 10 7 d yr 1 , which may be interpreted by mass transfer from the less massive to the more massive component. As period increases, the separation between components may increase, which will cause the contact degree to decrease. With mass transferring, the spin angular momentum will increase, while the orbital angular momentum will decrease. Only if the contact configuration would merge at J spin 〉1/3 J orb could this kind of deep-contact binary with period increasing, such as EF Dra, evolve into a rapidly-rotating single star.

关键词： stars (including multiple): binaries: close — stars: individual (EF Draconis)

TZ Lyrae:an Algol-type Eclipsing Binary with Mass Transfer

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Chinese Journal of Astronomy and Astrophysics 2007年第2期7卷 258-264页

作者： yuan-gui yang Xin-Guo Yin Physics Department of Huaibei Coal Industry Teachers College Huaibei 235000

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.

关键词： stars binaries close - stars binaries eclipsing - stars individual TZ Lyrae

PS Vir:a short-period solar-like contact binary

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Research in Astronomy and Astrophysics 2018年第7期18卷 45-52页

作者： Hui-Yu yuan Hai-Feng Dai yuan-gui yang Information College Huaibei Normal University School of Physics and Electronic Information Huaibei Normal University

We present multi-color photometric observations and a one-dimensional spectrum, acquired from March 2016 to May 2017, for the short-period eclipsing binary PS Vir, by using the 2.16-m, 85-cm and 60-cm telescopes at Xinglong station, which is administered by National Astronomical Observatories, Chinese Academy of Sciences. The spectral type was determined as G2V from the one-dimensional spectrum. The photometric solution was reduced from BVRc light curves. The results imply that PS Vir is a W-subtype contact binary with a mass ratio of q - 0.305（zk0.008） and a fill-out factor of f = 14.4（＋1.8）%. The orbital period may be undergoing a cyclic oscillation with an ampli-tude of A = 0.0027（~0.0001）d and a modulated period of 11.7（4-0.2） yr, which may result from the light-time effect due to a third body. The lower limit on mass for the assumed component is 0.12 Me. Moreover, the more massive component of PS Vir may be a bit more evolved star as determined from the mass-luminosity diagram.

关键词： binaries close-binaries eclipsing-stars individual(PS Vir)-stars

IU Cancri:a solar-type contact binary with mass transfer

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Research in Astronomy and Astrophysics 2019年第6期19卷 89-96页

作者： Hui-Yu yuan Hai-Feng Dai yuan-gui yang Information College Huaibei Normal University Huaibei 235000 China School of Physics and Electronic Information Huaibei Normal University Huaibei 235000 China

We present new CCD photometry of the solar-type contact binary IU Cnc, which was observed from November 2017 to March 2018 with three small telescopes in China. BV light curves imply that IU Cnc is a W-type contact binary with total eclipses. The photometric solution indicates that the mass ratio and fill-out factor are q = 4.104 ± 0.004 and f = 30.2%± 0.3%, respectively. From all available light minimum times, the orbital period may increase at a rate of dP/dt =+6.93(4)× 10^-7 d yr^-1, which may result from mass transfer from the secondary component to the primary one. With mass transferring,IU Cnc may evolve from a contact configuration into a semi-detached configuration.

关键词： binaries:close-binaries eclipsing-stars individual(IU Cancri)

New photometric studies for two deep,low-mass ratio overcontact binaries:Y Sex and V1363Ori

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Research in Astronomy and Astrophysics 2021年第11期21卷 189-201页

作者： yuan-gui yang Shuang Wang Hui-Yu yuan Hai-Geng Dai School of Physics and Electronic Information Huaibei Normal UniversityHuaibei 235000China

We present new photometry for two contact binaries,Y Sex and V1363 Ori,which were observed by three small telescopes in *** using the W-D method,the absolute parameters are updated from new BVR light curves and previous radial velocity *** identify that two binaries are deep,lowmass ratio(DLMR)overcontact binaries with q≤0.25 and f≥50%.From the temperature-luminosity diagram,the primary components are slightly evolved main-sequence stars,whose evolutionary ages are~2.51 Gyr for Y Sex and~3.56 Gyr for V 1363 Ori,*** the(O-C)curves,it is found that the orbital periods may be undergoing secular increase with cyclic variations,which may be interpreted either by magnetic activity cycles or by the light-time orbit *** period increasing,this kind of DLMR overcontact binaries,such as Y Sex and V1363 Ori,will evolve into the rapid-rotating single stars.

关键词： binaries(including multiple):close binaries:eclipsing stars:fundamental parameters stars:individual(Y Sex,V1363 Ori)

A photometric-spectroscopic study of the infrared-excess eclipsing binary V2364 Cyg

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Research in Astronomy and Astrophysics 2020年第12期20卷 307-316页

作者： Hui-Yu yuan Lin-Qiao Jiang Hai-Feng Dai Shuang Wang yuan-gui yang Information College&School of Physics and Electronic Information Huaibei Normal UniversityHuaibei 235000China Artificial Intelligence Key Laboratory of Sichuan Province Sichuan University of Science&EngineeringZigong 643000China

The eclipsing binary V2364 Cyg is an A7 V-type contact binary with a period of 0.5921 *** present six spectra from LAMOST and BVRc light curves(LCs),which are simultaneously analyzed to obtain the absolute physical *** first light maxima are brighter than the second ones by up to 0.m038,0.m036 and 0.m024 for BVRc bands,*** distorted LCs are modeled by a cool spot on the less massive *** mass ratio and over-contact degree are q=0.319(±0.004) and f=28.4%(±1.0) % *** the mass-luminosity diagram,the primary component is a normal main-sequence star,while the secondary one is a subgiant *** the(O-C) curve,the orbital period secularly decreases at a rate dP/dt=-1.62(±0.03) × 10^-7 dyr^-1,which is mainly attributed to mass loss via stellar wind from the binary *** may result in the observed infrared excess in the W4 band.

关键词： stars:circumstellar matter stars:binaries:close stars:individual(V2364 Cyg) mass loss infrared excess

Period studies and photometric models for two EB-type binaries EU Hya and AW Vul

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Research in Astronomy and Astrophysics 2016年第2期16卷 127-134页

作者： yuan-gui yang Qun Li Hua-Li Li Hai-Feng Dai School of Physics and Electronic Information/Information College Huaibei Normal UniversityHuaibei 235000China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of SciencesKunming 650011China National Astronomical Observatories Chinese Academy of SciencesBeijing 100012China

New photometry for two Algol-type binaries, 0.8065 d）, was carried out using the 60-cm telescope EU Hya （P = 0.7782 d） and AW Vul （P = at Xinglong station of National Astronomical Observatories, Chinese Academy of Sciences. With the updated Wilson-Devinney code, photometric el- ements were derived from the multi-color light curves. The modeled results indicate that the two systems are near-contact binaries, whose secondary components fill their Roche lobes. The fill-out factors of the primaries are fp = 81.2 （±0.2）% for EU Hya and fp --- 82.4 （±0.3）% for AW Vul. Period analysis implies that there exists a downward parabola with a light-time orbit from the （O - C） curve. This kind of periodic oscillation may be attributed to the light-time orbit effect of a third companion. The long-term period de- crease may be caused by mass and angular momentum loss. When the orbital period decreases, the fill-out factor of fp will increase. Our results indicate that the primaries will also eventually fill their Roche lobes. EU Hya and AW Vul may possibly evolve from semi-detached binaries into contact ones.

关键词： eclipsing binaries -- stars individual (EU Hya and AW Vul) -- the third companion

OO Aquilae:a solar-type contact binary with intrinsic light curve changes

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Research in Astronomy and Astrophysics 2016年第1期16卷 13-22页

作者： Hua-Li Li Jian-Yan Wei yuan-gui yang Hai-Feng Dai Key Laboratory of Space Astronomy and Technology National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100012China University of Chinese Academy of Sciences Beijing 100049China School of Physics and Electronic Information Huaibei Normal UniversityHuaibei 235000China

New multi-color photometry of the solar-type contact binary OO Aql was obtained in 2012 and2013, using the 60 cm telescope at Xinglong Station of the National Astronomical Observatories, Chinese Academy of Sciences. From two sets of light curves LC_1 and LC_2, photometric models were performed by using the 2003 version of the Wilson-Devinney code. The overcontact factor of the binary system was determined to be f = 37.0（±0.5）%. The intrinsic variability of this binary occurs in light maxima and minima, which could result from a possible third component and magnetic activity of the late type components. Based on all available light minimum times, the orbital period may change in a complicated mode,i.e., sudden period jumps or continuous period variations. The period of OO Aql may possibly undergo a secular period decrease with a rate of d P /dt =-3.63（±0.30） × 10^（-8）d yr^（-1）, superimposed by two possible cyclic variations in the O- C curve. The long-term period decrease may be interpreted as conserved mass transfer from the more massive component to the less massive one. The 21.5-yr oscillation may be attributed to cyclic magnetic activity, and the 69.3-yr one may result from the light-time effect of an unseen tertiary body.

关键词： binaries: close -- binaries: eclipsing -- stars: individual (OO Aql)

A photometric study of the K-type contact binary EI CVn

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Research in Astronomy and Astrophysics 2011年第2期11卷 181-190页

作者： yuan-gui yang School of Physics and Electronic Information,Huaibei Normal University,Huaibei 235000,China School of Physics and Electronic Information Huaibei Normal University Huaibei 235000 China

We present charge-coupled device （CCD） photometry for the short-period K-type binary EI CVn,observed on 2009 February 28 at the Xinglong Station of National Astronomical Observatories,Chinese Academy of *** using the Wilson-Devinney program,the photometric solution was first deduced from our V R *** results show that EI CVn is a W-type weak-contact binary with a mass ratio of qph=0.2834（±0.0010） and an overcontact degree of f=20.0%（±0.7%）.The distorted light curves were modeled by a dark spot on the cool primary component,whose area was up to 1.9% of the area of the *** on the period analysis,it is found that there exists a weak secular decrease at a rate of dP/dt= 3.11（±0.03） × 10-7 d yr-1,which may be attributed to mass transfer from the primary to the *** mass transfer occurring,the separation between both components will shrink,which may cause the degree of overcontact to ***,the weak-contact binary EI CVn may evolve into a deep-contact configuration.

关键词： stars: binaries: close -- stars: binaries: eclipsing -- stars: individual: EICVn