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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）

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

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 China.By using the W-D method,the absolute parameters are updated from new BVR light curves and previous radial velocity curves.Results 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,respectively.From 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 effect.With 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 d.We present six spectra from LAMOST and BVRc light curves(LCs),which are simultaneously analyzed to obtain the absolute physical parameters.The first light maxima are brighter than the second ones by up to 0.m038,0.m036 and 0.m024 for BVRc bands,respectively.These distorted LCs are modeled by a cool spot on the less massive component.Its mass ratio and over-contact degree are q=0.319(±0.004) and f=28.4%(±1.0) % respectively.From the mass-luminosity diagram,the primary component is a normal main-sequence star,while the secondary one is a subgiant star.From 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 system.This 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）

The ROSAT bright source 1RXS J201607.0+251645:an active Algol-type binary

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Research in Astronomy and Astrophysics 2009年第9期9卷 1035-1048页

作者： Hua-Li Li yuan-gui yang Wei Su Hui-Juan Wang Jian-Yan Wei National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China National Astronomical Observatories / Urumqi Observatory Chinese Academy of Sciences Urumqi830011 China Graduate University of Chinese Academy of Sciences Beijing 100049 China School of Physics and Electric Information Huaibei Coal Industry Teachers College Huaibei235000 China

1RXS J201607.0＋251645 is identified as an eclipsing binary. We present preliminary observations in the V band with the 0.6-m telescope for three years and extensive observations in the V and R bands with the 0.8-m telescope for six nights, respectively. The light curve of the system is E13 type. Five light minimum times were obtained and the orbital period of 0.388058^d（±0.00044d） is determined. The photometric solution given by the 2003-version of the Wilson-Devinney program suggests that the binary is a semidetached system with photometric mass ratio 0.895（±0.006）, which is probably comprised of a G5 primary and an oversized K5 secondary. The tess massive component has completely filled its Roche lobe, while the other one almost fills its Roche lobe with a filling factor of 93.4%. The system shows a varying O＇Connell effect in its phase folded diagrams from 2005 to 2007, and is X-ray luminous with log Lx/Lbol - -3.27. Possible mechanisms to account for these two phenomena are discussed. Finally, we infer that the binary may be in thermal oscillation or may evolve into a contact binary.

关键词： stars： binaries： close -- stars： binaries： eclipsing -- stars： individual： 1RXSJ201607.0＋251645 HD 339946

GRB 190530A:From Precursor,Prompt Emission to Afterglow all Originated from Synchrotron Radiation

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Research in Astronomy and Astrophysics 2022年第6期22卷 22-32页

作者： Hui-Ya Liu Xiang-Gao Wang Li-Ping Xin Zi-Min Zhou Liang-Jun Chen Bing Li yuan-gui yang Qi Luo Cheng-Kui Li Shao-Lin Xiong Ling-Jun Wang Xu-Hui Han Li-Ming Song Jian-Yan Wei En-Wei Liang Shuang-Nan Zhang Guangxi Key Laboratory for Relativistic Astrophysics Department of PhysicsGuangxi UniversityNanning 530004China GXU-NAOC Center for Astrophysics and Space Sciences Nanning 530004China CAS Key Laboratory of Space Astronomy and Technology National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China Key Laboratory of Particle Astrophysics Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China School of Physics and Electronic Information Huaibei Normal UniversityHuaibei 235000China

GRB 190530A was jointly observed by the High Energy X-ray Telescope of the Hard X-ray Modulation Telescope(Insight-HXMT/HE)and the Ground-Based Wide-Angle Camera network(GWAC-N)with the extremely large field of view.After triggered by Insight-HXMT/HE and Fermi/GBM,we observed the optical emission of GRB 190530A,using the 30 cm telescope of GWAC(GWAC-F30)to search and locate its position.Subsequent observation of the late afterglow of GRB 190530A was made with the 2.16 m telescope at Xinglong Observatory.In this paper,we make a detailed exploration of the origin of GRB 190530A.In the prompt emission,a“double-tracking”pattern is presented both for the low-energy spectral indexαand the peak energy Epin the Band function with Insight-HXMT/HE and Fermi/GBM data;the results of GRB 190530A are consistent with the Amati and Yonetoku correlations;the spectral lag(τ)versus energy(E)can be estimated withτ=-3.0±0.06+(0.17±0.03)logE.The synchrotron radiation can account for the origin of GRB190530A prompt emission behaviors.Theαand Epof the precursor are essentially the same as that of the main prompt emission,implying that they have the same origin.For the afterglow,it can be described with the external forward shock model in ISM circumburst medium.In summary,from precursor,prompt emission to afterglow of GRB 190530A all originated from synchrotron radiation.

关键词： (stars)gamma-ray burst:individual(GRB 190530A)-(stars)gamma-ray burst general-virtual observatory tools

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)