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The first photometric analysis of the totally eclipsing contact binary V811 Cep

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Research in Astronomy and Astrophysics 2021年第8期21卷 99-105页

作者：高翔李凯高兴刘媛 Shandong Provincial Key Laboratory of Optical Astronomy and Solar-Terrestrial Environment Institute of Space SciencesShandong UniversityWeihai 264209China Xinjiang Astronomical Observatory Urumqi 830011China Qilu Institute of Technology Jinan 250200China

The first photometric analysis of V811 Cep was carried *** first complete light curves of V,R and I bands are *** analysis was carried out by the Wilson-Devinney(W-D)program,and the results show that V811 Cep is a median-contact binary(f=33.9(±4.9)%)with a mass ratio of *** is a W-subtype contact binary,that is,the component with less mass is hotter than the component with more mass,and the light curves are asymmetric(O’Connell effect),which can be explained by the existence of a hot spot on the component with less *** orbital inclination is i=88.3°,indicating that it is a totally eclipsing binary,so the parameters obtained are *** the O-C analyzing,it is found that the orbital period decreases at the rate of P=-3.90(±0.06)×10^(-7)d yr^(-1),which indicates that the mass transfer occurs from the more massive component to the less massive one.

关键词： binaries:close binaries:eclipsing stars:evolution stars:individual(V811 Cep)

Eclipsing binary XZ CMi in a hierarchical quadruple system

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Research in Astronomy and Astrophysics 2020年第8期20卷 307-315页

作者： Zhi-Hua Wang Li-Ying Zhu Yunnan Observatories Chinese Academy of SciencesKunming 650216China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of SciencesKunming 650216China Center for Astronomical Mega-Science Chinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China

The new complete BV Rc Ic light curves and spectra of the short-period eclipsing binary XZ CMi are *** 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 *** 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 *** 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)***,we found a visual companion star at 2.4′′east by south of this system at a much greater distance by direct *** 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 *** similar parallax and proper motion imply that the components of this hierarchical quadruple system might be bounded by *** observations for two visual components were carried out by the LAMOST and 2.16 m telescopes,*** different values of[Fe/H]suggest that they were not born from the same ***,XZ CMi system is an interesting and important target to study the formation of the multiple stars.

关键词： binaries:close binaries:eclipsing stars:individual(XZ CMi)

The initial and final state of SNe Ia from the single degenerate model

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Science China(Physics,Mechanics & Astronomy) 2010年第9期53卷 1732-1738页

作者： MENG XiangCun1,YANG WuMing1 & LI ZhongMu2,3 1School of Physics and Chemistry,Henan Polytechnic University,Jiaozuo 454000,China 2Institute for Astronomy and History of Science and Technology,Dali University,Dali 671003,China 3National Astronomical Observatories,Chinese Academy of Sciences,Beijing 100012,China School of Physics and Chemistry Henan Polytechnic University Jiaozuo China Institute for Astronomy and History of Science and Technology Dali University Dali China National Astronomical Observatories Chinese Academy of Sciences Beijing China

Although type Ia supernovae(SNe Ia) show their importance in many astrophysical fields,the nature of the progenitors of SNe Ia is still *** present,the single degenerate(SD) model is presented to be a very likely progenitor *** the comprehensive SD model developed by Meng & Yang(2010),we show the initial and final state of the progenitor systems of SNe Ia in an orbital period—the secondary mass(log Pi,M2i) *** results may explain the location of some supersoft X-ray sources and recurrent novae in the(log Pi,M2i) plane,and be helpful to judge whether an SD system is the potential progenitor system of SNe Ia,as well as to simulate the interaction between SN ejecta and its companion.

关键词： binaries:close stars:evolution supernovae:general white dwarfs

The formation of neutron star systems through accretion-induced collapse in white-dwarf binaries

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Research in Astronomy and Astrophysics 2020年第9期20卷 135-158页

作者： Bo Wang Dongdong Liu Yunnan Observatories Chinese Academy of SciencesKunming 650216China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of SciencesKunming 650216China Center for Astronomical Mega-Science Chinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China

The accretion-induced collapse(AIC)scenario was proposed 40 years ago as an evolutionary end state of oxygen-neon white dwarfs(ONe WDs),linking them to the formation of neutron star(NS)***,there has been no direct detection of any AIC event so far,even though there exists a lot of indirect observational ***,the evolutionary pathways resulting in NS formation through AIC are still not thoroughly *** this article,we review recent studies on the two classic progenitor models of AIC events,i.e.,the single-degenerate model(including the ONe WD+MS/RG/He star channels and the CO WD+He star channel)and the double-degenerate model(including the double CO WD channel,the double ONe WD channel and the ONe WD+CO WD channel).Recent progress on these progenitor models is reviewed,including the evolutionary scenarios leading to AIC events,the initial parameter space for producing AIC events and the related objects(e.g.,the pre-AIC systems and the post-AIC systems).For the single-degenerate model,the pre-AIC systems(i.e.,the progenitor systems of AIC events)could potentially be identified as supersoft X-ray sources,symbiotics and cataclysmic variables(such as classical novae,recurrent novae,Ne novae and He novae)in the observations,whereas the post-AIC systems(i.e.,NS systems)could potentially be identified as low-/intermediate-mass X-ray binaries,and the resulting low-/intermediate-mass binary pulsars,most notably millisecond *** the double-degenerate model,the pre-AIC systems are close double WDs with short orbital periods,whereas the post-AIC systems are single isolated NSs that may correspond to a specific kind of NS with peculiar *** also review the predicted rates of AIC events,the mass distribution of NSs produced via AIC and the gravitational wave(GW)signals from double WDs that are potential GW sources in the Galaxy in the context of future spacebased GW detectors,such as LISA,TianQin,Taiji,*** theoretical and

关键词： binaries:close white dwarfs supernovae:general stars:neutron stars:evolution

Photometric investigation of eight ultra-short period eclipsing binaries from OGLE

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Research in Astronomy and Astrophysics 2020年第8期20卷 113-120页

作者： Shanti Priya D. Ravi Raja P. Rukmini J. Raghu Prasad M. Vineet S.Thomas Department of Astronomy Osmania UniversityHyderabad-500007TelanganaIndia The University of Akron AkronOH44325USA

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)~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.

关键词： stars:low-mass stars:evolution stars:low-mass binaries:eclipsing binaries:close

Explaining recently studied intermediate luminosity optical transients(ILOTs)with jet powering

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Research in Astronomy and Astrophysics 2021年第4期21卷 193-201页

作者： Noam Soker Noa Kaplan Department of Physics TechnionHaifa3200003Israel Guangdong Technion Israel Institute of Technology Shantou 515069China

We apply the jet-powered ILOT scenario to two recently studied intermediate luminosity optical transients(ILOTs),and find the relevant shell mass and jets’energy that might account for the outbursts of these *** the jet-powered ILOT scenario,an accretion disk around one of the stars of a binary system launches *** interaction of the jets with a previously ejected slow shell converts kinetic energy to thermal energy,part of which is radiated *** apply two models of the jet-powered ILOT *** the spherical shell model,the jets accelerate a spherical shell,while in the cocoon toy model the jets penetrate into the shell and inflate hot bubbles,the *** find consistent *** the ILOT(ILRT:intermediate luminosity red transient)SNhunt120 we find the shell mass and jets’energy to be Ms■0.5-1 M☉and E2 j■5×10^(47)erg,*** jets’half opening angle isαj■30°-60°.For the second peak of the ILOT(luminous red nova)AT 2014 ej we find these quantities to be Ms1-2 M☉and E2 j1.5×10^(48)erg,withαj■20°-30°.The models cannot tell whether these ILOTs were powered by a stellar merger that leaves one star,or by mass transfer where both stars *** both cases the masses of the shells and energies of the jets suggest that the binary progenitor system was massive,with a combined mass of M1+M210■M☉.

关键词： binaries:close stars:jets stars:variables:general

A photometric study of two neglected eclipsing binaries

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Research in Astronomy and Astrophysics 2021年第7期21卷 192-198页

作者： V.Kudak M.Fedurco V.Perig S.Parimucha Laboratory of Space Researches Uzhhorod National UniversityUzhhorodDaleka Str.2A88000Ukraine Institute of Physics Faculty of ScienceUniversity of P.J.SafarikKosicePark Angelinum 904001Slovakia

We present the first BVR photometry,period variation and photometric light curve analysis of two poorly studied eclipsing binaries,V1321 Cyg and CR *** were carried out from November 2017 to January 2020 at the observatory of Uzhhorod National *** variations were studied using all available early published as well as our minima *** used the newly developed ELIS a code for the light curve analysis and determination of photometric parameters for both *** 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 *** significant period changes in this system are *** Tau is,on the other hand,a semi-detached system where the secondary component almost fills its Roche *** 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.

关键词： binaries:close binaries:eclipsing stars:individual(V1321 Cyg CR Tau)

Modeling the high-energy emission from the gamma-ray binary 1FGL J1018.6–5856

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Research in Astronomy and Astrophysics 2021年第8期21卷 46-58页

作者： A-Ming Chen Chowing Ng Jumpei Takata Yun-Wei Yu School of physics Huazhong University of Science and TechnologyWuhan 430074China Department of Physics The University of Hong KongPokfulam RoadHong KongChina College of Physical Science and Technology Central China Normal UniversityWuhan 430079China

1FGL J1018.6–5856 is a high mass gamma-ray binary containing a compact object orbiting around a massive star with a period of 16.544 *** the compact object is a pulsar,non-thermal emissions are likely produced by electrons accelerated at the termination shock,and may also originate from the magnetosphere and the un-shocked wind of the *** this paper,we investigate the non-thermal emissions from the wind and the shock with different viewing geometries and study the multi-wavelength emissions from 1FGL J1018.6–*** present the analysis results of the Fermi/LAT using nearly 10 years of *** phase-resolved spectra indicate that the Ge V emissions comprise a rather steady component that does not vary with orbital motion and a modulated component that shows flux maximum around inferior *** ke V/Te V light curves of 1FGL J1018.6–5856 also exhibit a sharp peak around inferior conjunction,which are attributed to the boosted emission from the shock,while the broad sinusoidal modulations could be originating from the deflected shock tail at a larger *** modulations of Ge V flux are likely caused by the boosted synchrotron emission from the shock and the IC emission from the unshocked pulsar wind,while the steady component comes from the outer gap of the pulsar ***,we discuss the similarities and differences of 1FGL J1018.6–5856 with other binaries,like LS 5039.

关键词： binaries:close gamma rays:stars X-rays:binaries radiation mechanisms:non-thermal

Reanalysis of the orbital period variations of two DLMR overcontact binaries:FG Hya and GR Vir

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Research in Astronomy and Astrophysics 2017年第12期17卷 95-100页

作者： Xu-Dong Zhang Yun-Xia Yu Fu-Yuan Xiang Ke Hu Department of Physics Xiangtan University411105 XiangtanChina

We investigate orbital period changes of two deep, low mass ratio（DLMR） overcontact W UMa-type binaries, FG Hya and GR Vir. It is found that the orbital period of FG Hya shows a cyclic change with a period of Pmod= 54.44 yr. The cyclic oscillation may be due to a third body in an eccentric orbit, while the orbital period of GR Vir shows a periodic variation with a period of Pmod= 28.56 yr and an amplitude of A = 0.0352 d. The periodic variation of GR Vir can be interpreted as a result of either the light-time effect of an unseen third body or the magnetic activity cycle.

关键词： binaries:close binaries:eclipsing stars:individual(FG Hya,GR Vir)