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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 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

TV Mon - post mass transfer Algol type binary with δ Scuti pulsations in primary component.

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arXiv 2024年

作者： Kovalev, Mikhail Li, Zhenwei Xiong, Jianping Matekov, Azizbek Bo, Zhang Chen, Xuefei Han, Zhanwen Yunnan Observatories China Academy of Sciences Kunming650216 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming650011 China International Centre of Supernovae Yunnan Key Laboratory Kunming650216 China University of Chinese Academy of Sciences Yuquan Road 19 Sijingshang Block Beijing100049 China Ulugh Beg Astronomical Institute Uzbekistan Academy of Sciences 33 Astronomicheskaya str. Tashkent100052 Uzbekistan Key Laboratory of Optical Astronomy National Astronomical Observatories Chinese Academy of Sciences Beijing100101 China

We present a study of the detached eclipsing binary TV Mon using spectra from the LAMOST medium-resolution survey and ASAS-SN, CoRoT photometry. We apply multiple-epochs spectral fitting to derive RV and spectral parameters. The analysis of eclipses in CoRoT data show the relative sizes of the stellar components and almost edge-on circular orbit. Combining the spectral and photometrical solutions we estimate masses and radii of the components: MA,B = 2.063 ± 0.033(stat.) ± 0.095(syst.), 0.218 ± 0.004(stat.) ± 0.018(syst.) M☉, RA,B = 2.394 ± 0.014, 2.860 ± 0.016 R☉. SED analysis and Gaia parallax allow us to get estimation of temperatures Teff A,B = 7624+−194174, 5184+−130123 K and distance d = 907 ± 11 pc. We identify three δ Scuti type pulsation frequencies in the primary component, while we also suspect TV Mon having a spot activity in the secondary component. This system experienced intensive mass transfer and mass ratio reversal in the past, but currently shows no signs of mass transfer in the spectra. The low mass component will lose its outer envelope and shrink to the helium white dwarf, the mass and orbital period of which are in good agreement with evolutionary models predictions. Copyright © 2024, The Authors. All rights reserved.

关键词： White dwarfs

A comparative analysis of two peculiar long Gamma-ray bursts: GRB 230307A and GRB 211211A

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arXiv 2024年

作者： Peng, Zhao-Yang Chen, Jia-Ming Mao, Jirong College of Physics and Electronics Information Yunnan Normal University Kunming650500 China School of Physics and Astronomy Yunnan University Kunming650500 China Yunnan Observatories Chinese Academy of Sciences Kunming650011 China Center for Astronomical Mega-Science Chinese Academy of Sciences Beijing100101 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming650011 China

GRB 211211A is a peculiar long Gamma-ray burst (GRB) with very high brightness and short burst properties. It’s full lightcurve consists of three emission episodes, i.e. a precursor, a main burst and a extended emission. We find a recently detected long-duration GRB 230307A also includes the three consistent emission episodes. Furthermore, the two bursts have similar redshift 0.076 and 0.065, respectively. We perform a detail temporal and spectral analysis of the two GRBs to compare their temporal and spectral properties. Our analysis shows that the two bursts share great similarities for both the whole emission and the three corresponding emission phases, which are listed as follows: (1) they have near zero spectral lag, (2) they have very short minimum variability timescale (MVT), (3) they lie in the same region of in the MVT-T90, Amati relation, and hardness-T90 planes, (4) the three phases are quasi-thermal spectra, (5) both the peak energy and the low-energy index track the flux, (6) the time-resolved spectra are much wider than those of the blackbody prediced by theory model, (7) there are strong correlations between thermal flux and total flux and the correlation coefficients as well as the slopes for the corresponding stages are very consistent, (8) the photosphere emission properties are very consistent. Other investigations and observations suggest the two GRBs indeed belong to short burst with a compact star merger origin. Therefore, we think that GRB 230307A and GRB 211211A are the rare and similar GRBs and the photospheric radiation can interpret their radiation mechanisms. Copyright © 2024, The Authors. All rights reserved.

关键词： Spectrum analysis

On the External Inverse Compton Scattering off the Prompt Emission in GRB 221009A

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arXiv 2024年

作者： Dai, Cui-Yuan Zheng, Jian-He Zhao, Xiao-Hong Liu, Ruo-Yu Wang, Xiang-Yu School of Astronomy and Space Science Nanjing University Nanjing210023 China Ministry of Education Nanjing210023 China Yunnan Observatories Chinese Academy of Sciences Kunming650011 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Science Kunming650011 China Center for Astronomical Mega-Science Chinese Academy of Science 20A Datun Road Chaoyang District Beijing100012 China

The light curve of the TeV emission in GRB 221009A displays a smooth transition from an initial rapid rise to a slower rise and eventually a decay phase. The smooth temporal profile of the TeV emission suggests that it mainly results from an external shock. The temporal overlap between the prompt KeV-MeV emission and the early TeV afterglow indicates that external inverse Compton scattering (EIC) between the prompt KeV-MeV photons and the afterglow electrons is inevitable. Since the energy density of the prompt emission is much higher than that of the afterglow during the early phase, the EIC process dominates the cooling of afterglow electrons. The EIC scattering rate is influenced by the anisotropy of the seed photon field, which depends on the radii of the internal dissipation (Rdis), where the prompt emission is produced, and that of the external shock (Rext), where the afterglow emission is produced. We investigate the EIC process for different values of Rdis/Rext. We find that, for varying Rdis/Rext, the EIC scattering rate can differ by a factor of ∼ 2. For GRB 221009A, the EIC emission is dominated during the early rising phase of the TeV afterglow. It then transitions to a phase dominated by the synchrotron self-Compton (SSC) emission as the intensity of the prompt emission decreases. Additionally, we investigate the effect of γγ absorption in the TeV afterglow caused by prompt MeV photons and find that it is insufficient to explain the early rapid rise in the TeV afterglow, even in the case of Rdis/Rext ∼ 1. Copyright © 2024, The Authors. All rights reserved.

关键词： Photons

A New Deep and Low-Mass-Ratio Contact Binary V2769 Orionis

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SSRN

SSRN 2023年

作者： Meng, Fangbin Zhu, LiYing Matekov, Azizbek Kunming650216 China University of Chinese Academy of Sciences No.1 Yanqihu East Rd Huairou District Beijing101408 China Key Laboratory of the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming650216 China Ulugh Beg Astronomical Institute Uzbekistan Academy of Sciences 33 Astronomicheskaya str. Tashkent100052 Uzbekistan

We carried out the first multi-colour light curves analysis of the eclipsing binary V2769 Ori. The photometric solution was determined by applying the Wilson–Devinney method. The results show that V2769 Ori is a deep, low-mass-ratio contact binary with a mass ratio of q = 0.162(±0.003) and a contact degree of f = 55(±8)%. The total eclipse characteristics of V2769 Ori imply that the photometric solutions we obtained are reliable. With all available light minimum times, the O-C diagram was constructed and analyzed. The orbital period analysis reveals a long term period decrease at a rate of dp/dt = −1.24(±0.08) × 10−6 d yr−1 and a periodic oscillation with a period of 8.77 years. The secular period decrease can be explained by a combination of mass transfer from the more massive component to the less massive one and angular momentum loss via magnetic braking. As the orbital period decreases, the shrinking of the inner and outer critical Roche lobes causes an increase in contact degree, and the binary system will finally merge into a rapidly rotating star. Periodic oscillation may be the result of light-travel time effects due to the presence of unseen components. © 2023, The Authors. All rights reserved.

关键词： Travel time

CSS_J154915.7+375506: A low-mass-ratio marginal contact binary system with a hierarchical third body

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arXiv 2024年

作者： Wu, Jin-Feng Zhu, Li-Ying Matekov, Azizbek Li, Lin-Jia Ehgamberdiev, Shuhrat Asfandiyarov, Ildar Wang, Jiang-Jiao Zhang, Jia Meng, Fang-Bin Kunming650216 China University of Chinese Academy of Sciences No.1 Yanqihu East Rd Huairou District Beijing101408 China Key Laboratory of the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming650216 China Ulugh Beg Astronomical Institute of the Uzbekistan Academy of Science Astronomicheskaya 33 Tashkent100052 Uzbekistan National University of Uzbekistan 4 University str Tashkent100174 Uzbekistan

We presented the multi-filter light curves of CSS_J154915.7+375506 inaugurally, which were observed by the 1.5 m AZT-22 telescope at Maidanak Astronomical Observatory. A low-resolution spectrum obtained by LAMOST reveals it is an A-type close binary. By analyzing the BVRI total-eclipse light curves, we are able to derive a reliable photometric solution for this system, which indicates that CSS_J154915.7+375506 is an extremely low-mass-ratio (q=0.138) marginal contact binary system. The location in the HR diagram shows that its secondary component with a much smaller mass is the more evolved one, indicating the mass ratio reversal occurred. The present secondary component had transferred a significant amount of mass to the present primary one. By the combination of a total of 20 times of minimum, we investigated its O-C curve. A periodic oscillation and a possible period decrease have been detected. As the period decreases, the system will evolve towards the contact phase. This makes CSS_J154915.7+375506 a valuable case to study the formation scenario of contact binaries through mass reversal. The periodic oscillation suggested a third body with a minimal mass of 0.91 M☉, which is larger than that of the less massive component in the central binary. This implies that the secondary body was not replaced by the third body during early stellar interactions, indicating that it is a fossil system and retains its original dynamical information. © 2024, CC BY-NC-ND.

关键词： Systems (metallurgical)

The radius variations of accreting main sequence stars and mass transfer instability

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arXiv 2024年

作者： Zhao, Zi-Qi Li, Zhen-Wei Xiao, Lin Ge, Hong-Wei Han, Zhan-Wen Department of Physics Hebei University Baoding071002 China Hebei Key Laboratory of High-precision Computation and Application of Quantum Field Theory Baoding071002 China Hebei Research Center of the Basic Discipline for Computational Physics College of Physics Science and Technology Hebei University Baoding071002 China Yunnan Observatories Chinese Academy of Sciences Kunming650216 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Science China International Centre of Supernovae Yunnan Key Laboratory Kunming650216 China University of the Chinese Academy of Science Yuquan Road 19 Shijingshan Block Beijing100049 China

Many previous works studied the dynamical timescale mass transfer stability criteria based on the donor response with neglecting the stellar structure of the accretor. In this letter, we investigate the radial response of accretors with mass accumulation and its effect on the binary mass transfer stability. We perform a series of detailed stellar evolution simulations with different types of accretors and obtain the radial variations of stars accreting at different rates. Since the time within which the donor loses half of the original mass has a correlation with the donor mass, we approximately obtain the mean mass transfer rate as a function of mass ratio. Assuming that the common envelope (CE) phase occurs if the accretor radius exceeds the outer Roche lobe radius, we obtain the critical mass ratio of dynamically unstable mass transfer. We find the critical mass ratios for donors filling their Roche lobes at the Main Sequence (MS) and Hertzsprung Gap (HG) stages are smaller than that derived from the radial response of the donor in the traditional way. Our results may suggest that the binary is easier to enter into the CE phase for a donor star at the MS or HG stage than previously believed. Copyright © 2024, The Authors. All rights reserved.

关键词： Mass transfer

Timing and spectral analysis of GK Persei during the 2010 dwarf nova outburst

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arXiv 2025年

作者： Pei, Songpeng Zhang, Xiaowan Li, Qiang Ou, Ziwei Yang, Taozhi Cai, Yongzhi School of Physics and Electrical Engineering Liupanshui Normal University Guizhou Liupanshui553004 China Qiannan Normal University for Nationalities Duyun558000 China Qiannan Key Laboratory of Radio Astronomy Guizhou Province Duyun558000 China Tsung-Dao Lee Institute Shanghai Jiao Tong University Shanghai201210 China Ministry of Education Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter School of Physics Xi’an Jiaotong University Xi’an710049 China Yunnan Observatories Chinese Academy of Sciences Kunming650216 China International Centre of Supernovae Yunnan Key Laboratory Kunming650216 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming650216 China

GK Persei, an old nova and intermediate polar (IP), exhibited a dwarf nova (DN) outburst in 2010. This outburst was extensively observed by the Neil Gehrels Swift Observatory, beginning 1.95 days after the eruption and continuing until 13.9 days before the maximum of the outburst in the optical. In this paper, we present timing and spectral analyses, comparing the results with those of other outbursts. We confirm the spin modulation in the 2 − 10 keV X-ray range with a period of PWD = 351.325(9) s. Additionally, we detected spin modulation in the 0.3 − 2 keV band during the second half of the observations, a feature not seen in the 2015 and 2018 outbursts. This finding suggests that the soft X-ray emission in GK Per may originate partly near the magnetic poles and partly from a wind or circumstellar material. Copyright © 2025, The Authors. All rights reserved.

关键词： Spectrum analyzers