检索结果-内蒙古大学图书馆

arXiv 2025年

作者： Peng, Jing-Qiang Zhang, Shu Shui, Qing-Cang Zhang, Shuang-Nan Kong, Ling-Da Chen, Yu-Peng Wang, Peng-Ju Ji, Long Qu, Jin-Lu Tao, Lian Ge, Ming-Yu Chang, Zhi Li, Jian Li, Zhao-Sheng Yu, Zhuo-Li Yan, Zhe Key Laboratory of Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences Beijing100049 China University of Chinese Academy of Sciences Chinese Academy of Sciences Beijing100049 China Institute für Astronomie und Astrophysik Kepler Center for Astro and Particle Physics Eberhard Karls Universität Sand 1 TübingenD-72076 Germany School of Physics and Astronomy Sun Yat-Sen University Zhuhai519082 China CAS Key Laboratory for Research in Galaxies and Cosmology Department of Astronomy University of Science and Technology of China Hefei230026 China School of Astronomy and Space Science University of Science and Technology of China Hefei230026 China Key Laboratory of Stars and Interstellar Medium Xiangtan University Hunan Xiangtan411105 China Yunnan Observatories Chinese Academy of Sciences Kunming650216 China Key Laboratory for the Structure and Evolution Celestial Objects Chinese Academy of Sciences Kunming650216 China Center for Astronomical Mega-Science Chinese Academy of Sciences Beijing100012 China

Swift J1727.8–1613 is a black hole X-ray binary newly discovered in 2023. We perform spectral analysis with simultaneous Insight-HXMT, NICER and NuSTAR observations when the source was approaching to the hard intermediate state. Such a joint view reveals an additional hard component apart from the normally observed hard component with reflection in the spectrum, to be distinguished from the usual black hole X-ray binary systems. By including this extra component in the spectrum, we have measured a high spin of 0.98+0.02−0.07 and an inclination of around 40+1.2−0.8 degrees, which is consistent with NICER results reported before. However, we find that the additional spectral component can not be exclusively determined due to the model degeneracy. Accordingly, a possible jet/corona configuration is adjusted to account for the spectral fitting with different model trials. The extra component may originate either from a relativistic jet or a jet base/corona underneath a slow jet. Copyright © 2025, The Authors. All rights reserved.

关键词：

来源：评论

学校读者我要写书评

暂无评论

The fractions of post-binary-interaction stars and evolved blue straggler stars on the red giant branch of globular clusters

arXiv

引用

arXiv 2021年

作者： Wei, Dandan Wang, Bo Chen, Hailiang Wang, Haifeng Gong, Xiaobo Liu, Dongdong Jiang, Dengkai 396 Yangfangwang Guandu District Kunming650216 China Key Laboratory for the Structure and Evolution of Celestial Objects CAS Kunming650216 China University of Chinese Academy of Science Beijing100049 China Center for Astronomical Mega-Science Chinese Academy of Sciences Beijing100012 China South-Western Institute for Astronomy Research Yunnan University Kunming650500 China

The red giant branch (RGB) of globular clusters (GCs) is home to some exotic stars, which may provide clues on the formation of multiple stellar populations in GCs. It is well known that binary interactions are responsible for many exotic stars. Thus, it is important to understand what fraction of stars on the RGB of GCs is the result of binary interactions. In this paper, we performed a binary population synthesis study to track the number of post-binary-interaction (post-BI) stars that appear on the RGB, with particular emphasis on the evolved blue straggler stars (E-BSSs). Assuming an initial binary fraction of nearly 50%, we find that about half of the objects on the RGB (called giants) underwent the binary interactions, and that E-BSSs account for around 10% of the giants in our standard simulation. We also compare the properties of post-BI giants that evolved from different channels. We find that the initial orbital period and mass ratio distributions significantly affect the fraction of post-BI giants. Our results imply that the non-standard stars from binary interactions provide a non-negligible contribution to the RGB stars in GCs, which should be considered in future investigations of the origin of multiple stellar populations. Copyright © 2021, The Authors. All rights reserved.

关键词： Giant stars

来源：评论

学校读者我要写书评

暂无评论

1SWASP J034439.97+030425.5:a short-period eclipsing binary system with a close-in stellar companion

引用

Research in Astronomy and Astrophysics 2020年第4期20卷 31-38页

作者： Bin Zhang Sheng-Bang Qian Jing-Jing Wang Qi-Jun Zhi Ai-Jun Dong Wei Xie Li-Ying Zhu Lin-Qiao Jiang School of Physics and Electronic Science Guizhou Normal UniversityGuiyang 550001China Guizhou Provincial Key Laboratory of Radio Astronomy and Data Processing Guizhou Normal UniversityGuiyang 550001China Yunnan Observatories Chinese Academy of SciencesKunming 650216China Key Laboratory of the Structure and Evolution of Celestial Objects Chinese Academy of SciencesKunming 650216China University of Chinese Academy of Sciences Beijing 100049China Center for Astronomical Mega-Science Chinese Academy of SciencesBeijing 100101China China University of Petroleum-Beijing at Karamay Karamay 834000China School of Physics and Electronic Engineering Sichuan University of Science and EngineeringZigong 643000China

First multi-wavelength photometric light curves(LCs)of the short-period eclipsing binary(EB)1 SWASP J034439.97+030425.5(hereafter J0344)are presented and analyzed by using the 2013 version of the Wilson-Devinney(W-D)*** explain the asymmetric LCs of J0344,a cool star-spot on the less massive component was *** photometric solutions suggest that J0344 is a W-subtype shallow contact EB with a contact degree of f=4.9%±3.0%and a mass ratio of q=2.456±***,an obvious third light was detected in our *** calculated the average luminosity contribution of the third light to the total light,and that value reaches up to 49.78%.Based on the O-C method,the variations of the orbital period were studied for the first *** O-C diagram reveals a secular decrease superimposed on a cyclic *** orbital period decreases at a rate of d P/dt=-6.07×10-7 d yr-1,which can be explained by the mass transfer from the more massive component to the less massive ***,its O-C diagram also shows a cyclic oscillation with an amplitude of 0.0030 d and a period about 7.08 yr,which can be explained by the presence of a third body with a minimum mass of M3 min=0.15±0.02 M⊙.The third component may play an important role in the formation and evolution of J0344 by drawing angular momentum from the central system.

关键词： stars:binaries:close stars:binaries:eclipsing stars:individual(1SWASP J034439.97+030425.5)

来源：评论

学校读者我要写书评

暂无评论

Hot subdwarf atmospheric parameters, kinematics, and origins - Based on 1587 hot subdwarf stars observed in gaia DR2 and lamost DR7

arXiv

引用

arXiv 2021年

作者： Luo, Yangping Németh, Péter Wang, Kun Wang, Xi Han, Zhanwen Department of Astronomy China West Normal University Nanchong637002 China Astronomical Institute Czech Academy of Sciences Fričova 298 OndřejovCZ-251 65 Czech Republic *** F o tér 1 Malomsok8533 Hungary Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming650011 China

Based on the Gaia DR2 catalogue of hot subdwarf star candidates, we identified 1587 hot subdwarf stars with spectra in LAMOST DR7. We present atmospheric parameters for these stars by fitting the LAMOST spectra with Tlusty/Synspec non-LTE synthetic spectra. Combining LAMOST radial velocities and Gaia Early Data Release 3 (EDR3) parallaxes and proper motions, we also present the Galactic space positions, velocity vectors, orbital parameters and the Galactic population memberships of the stars. With our He classification scheme, we identify four groups of He rich hot subdwarf stars in the Teff − log g and Teff − log (nHe/nH) diagrams. We find two extreme He-rich groups (eHe-1 and eHe-2) for stars with log (nHe/nH) ≥ 0 and two intermediate He-rich groups (iHe-1 and iHe-2) for stars with −1 ≤ log (nHe/nH) Copyright © 2021, The Authors. All rights reserved.

关键词： Stars

来源：评论

学校读者我要写书评

暂无评论

AT2021acak: a candidate tidal disruption event found in the Zwicky Transient Facility survey

arXiv

引用

arXiv 2022年

作者： Li, Jie Wang, Zhong-Xiang Zheng, Dong Zhang, Ju-Jia Zhu, Li-Tao Chen, Zhang-Yi Department of Astronomy School of Physics and Astronomy Yunnan University Kunming650091 China Shanghai Astronomical Observatory Chinese Academy of Sciences 80 Nandan Road Shanghai200030 China Purple Mountain Observatory Chinese Academy of Sciences Nanjing210034 China Yunnan Observatories Chinese Academy of Sciences Kunming650216 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming650216 China Center for Astronomical Mega-Science Chinese Academy of Sciences 20A Datun Road Chaoyang District Beijing100012 China

We report a candidate tidal disruption event (TDE) found in the Zwicky Transient Facility (ZTF) survey data. This candidate, with its transient name AT2021acak, showed brightness increases of ∼1 mag around MJD 59500 and subsequent power-law–like brightness declines. We have conducted multiple optical spectroscopic observations with the 2.4-m Lijiang telescope and one observation at X-ray and ultraviolet (UV) bands with the Neil Gehrels Swift Observatory (Swift). The optical spectra of the source show broad H and He emission line and Fe emission features. Possible 0.3–2 keV X-ray and bright UV emission of the source was detected. We analyze the declines of the optical light curves, the emission features of the optical spectra, and the constructed broad-band UV and optical spectrum. The properties derived from the analyses are consistent with those of reported (candidate) TDEs, and in particular very similar to those of ASASSN-18jd. The identification is complicated by the host being likely an AGN, and thus further observations of the event and quiescent host are required in order to have a clear understanding of the nature of this transient event. © 2022, CC BY.

关键词： Luminance

来源：评论

学校读者我要写书评

暂无评论

NICER, NuSTAR and Insight-HXMT views to black hole X-ray binary SLX 1746–331

arXiv

引用

arXiv 2025年

We study the spectral and temporal properties of the black hole X-ray transient binary SLX 1746–331 during the 2023 outburst with NICER, NuSTAR, and Insight-HXMT observations. Through the joint fitting of the spectra from NICER, NuSTAR, and Insight-HXMT, the spin and inclination angles are measured for the first time as 0.85 ± 0.03 and 53 ± 0.5°, respectively. Accordingly, the mass of the compact star is updated from the previous lower limit of 3.3±2.1M☉ to 5.5 ± 3.6M☉, which is consistent with 5.2 ± 4.5M☉ measured with an empirical mass-luminosity correlation of BH samples. With more NICER observations covering the later decay of the outburst, we confirm that the entire outburst was dominated by the disk emissions, and the thermal spectrum follows F ∝ Tin3.974±0.003, till a luminosity of over than two magnitudes lower than the maximum of the outburst. Copyright © 2025, The Authors. All rights reserved.

关键词： Black holes

来源：评论

学校读者我要写书评

暂无评论

Test of binary spectral model on FEROS spectra. First estimation of the fundamental parameters for HD 20784

arXiv

引用

arXiv 2022年

作者： Kovalev, Mikhail Gebruers, Sarah Straumit, Ilya Yunnan Observatories China Academy of Sciences Kunming650216 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming650011 China Sternberg Astronomical Institute of M. V. Lomonosov Moscow State University Leninskie Gory Moscow119991 Russia Max Planck Institute for Astronomy HeidelbergD-69117 Germany Institute for Astronomy KU Leuven Celestijnenlaan 200D bus 2401 Leuven3001 Belgium Department of Astronomy The Ohio State University ColumbusOH43210 United States

We analyse spectra of 26 early-type stars, with suspected binarity, using a binary spectral model adapted for high-resolution FEROS spectra. We confirm seven SB2 candidates (AE Pic, ∊ Vol, HD 20784, HD 208433, HD 43519, HD 56024, CD-73 375A) and derive mass ratios and spectroscopic parameters for them. We find good agreement with theoretical models. For slightly evolved system HD 20784 we made the first estimation of the fundamental parameters and age log t = 8.5 yr. Copyright © 2022, The Authors. All rights reserved.

关键词： Stars

来源：评论

学校读者我要写书评

暂无评论

First Chromospheric Activity and Doppler Imaging Study of PW And Using a New Doppler Imaging Code: SpotDIPy

arXiv

引用

arXiv 2023年

作者： Bahar, Engin Şenavcı, Hakan V. Işık, Emre Hussain, Gaitee A.J. Kochukhov, Oleg Montes, David Xiang, Yue Department of Astronomy and Space Sciences Faculty of Science Ankara University Beşevler Ankara06100 Turkey Max-Planck-Institut für Sonnensystemforschung Justus-von-Liebig-Weg 3 Göttingen37077 Germany Department of Computer Science Turkish-German University Beykoz Istanbul34820 Turkey Keplerlaan 1 Noordwijk2201 AZ Netherlands Department of Physics and Astronomy Uppsala University Box 516 UppsalaSE-75120 Sweden Facultad de Ciencias Físicas Universidad Complutense de Madrid MadridE-28040 Spain Yunnan Observatories Chinese Academy of Sciences Kunming650216 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming650216 China

Measuring coverage of dark spots on cool stars is important in understanding how stellar magnetic activity scales with the rotation rate and convection zone depth. In this respect, it is crucial to infer surface magnetic patterns on G and K stars, to reveal solar-like stellar dynamos in action. Molecular bands serve as invaluable indicators of cool spots on the surfaces of stars, as they play a crucial role in enabling accurate assessments of the extent of spot coverage across the stellar surface. Therefore, more reliable surface images can be obtained considering the inversion of atomic lines with molecular bands. In this context, we simultaneously carry out Doppler imaging (DI) using atomic lines as well as Titanium Oxide (TiO) band profiles of PW And (K2 V) and also investigate chromospheric activity indicators for the first time in the literature, using the high-resolution spectra. The surface spot distribution obtained from the inversion process represents both atomic line and TiO-band profiles quite accurately. The chromospheric emission is also correlated with photospheric spot coverage, except during a possible flare event during the observations. We detect frequent flare activity, using TESS photometry. We also introduce a new open-source, Python-based DI code SpotDIPy that allows performing surface reconstructions of single stars using the maximum entropy method. We test the code by comparing surface reconstruction simulations with the extensively used DoTS code. We show that the surface brightness distribution maps reconstructed via both codes using the same simulated data are consistent with each other. © 2023, CC BY.

关键词： Stars

来源：评论

学校读者我要写书评

暂无评论

Monte-Carlo simulations on possible collimation effects of outflows to fan-beamed emission of ultraluminous accreting X-ray pulsars

arXiv

引用

arXiv 2022年

作者： Hou, X. You, Y. Ji, L. Soria, R. Zhang, S.N. Ge, M.Y. Tao, L. Zhang, S. Feng, H. Zhou, M. Tuo, Y.L. Song, L.M. Wang, J.C. Yunnan Observatories Chinese Academy of Sciences Kunming650216 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming650216 China Key Laboratory for Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences Beijing100049 China University of Chinese Academy of Sciences Chinese Academy of Sciences Beijing100049 China School of Physics and Astronomy Sun Yat-Sen University Zhuhai519082 China Sydney Institute for Astronomy School of Physics A28 The University of Sydney SydneyNSW2006 Australia Department of Astronomy Tsinghua University Beijing100084 China

Pulsating ultraluminous X-ray sources (PULXs) are accreting pulsars with apparent X-ray luminosity exceeding 1039 erg s−1. We perform Monte-Carlo simulations to investigate whether high collimation effect (or strong beaming effect) is dominant in the presence of accretion outflows, for the fan beam emission of the accretion column of the neutron stars in PULXs. We show that the three nearby PULXs (RX J0209.6−7427, Swift J0243.6+6124 and SMC X-3), namely the three musketeers here, have their main pulsed emission not strongly collimated even if strong outflows exist. This conclusion can be extended to the current sample of extragalactic PULXs, if accretion outflows are commonly produced from them. This means that the observed high luminosity of PULXs is indeed intrinsic, which can be used to infer the existence of very strong surface magnetic fields of ∼ 1013−14 G, possibly multipole fields. However, if strong outflows are launched from the accretion disks in PULXs as a consequence of disk spherization by radiation pressure, regular dipole magnetic fields of ∼ 1012 G may be required, comparable to that of the three musketeers, which have experienced large luminosity changes from well below their Eddington limit (2 × 1038 erg s−1 for a NS) to super-Eddington and their maximum luminosity fills the luminosity gap between Galactic pulsars and extragalactic PULXs. Copyright © 2022, The Authors. All rights reserved.

关键词： Luminance

来源：评论

学校读者我要写书评

暂无评论

Core overshoot constrained by the absence of a solar convective core and some solar-like stars

arXiv

引用

arXiv 2022年

作者： Zhang, Qian-Sheng Christensen-Dalsgaard, Jørgen Li, Yan Yunnan Observatories Chinese Academy of Sciences 396 Yangfangwang Guandu District Kunming650216 China Stellar Astrophysics Centre Department of Physics and Astronomy Aarhus University Aarhus CDK-8000 Denmark Center for Astronomical Mega-Science Chinese Academy of Sciences 20A Datun Road Chaoyang District Beijing100012 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences 396 Yangfangwang Guandu District Kunming650216 China University of Chinese Academy of Sciences Beijing100049 China

Convective-core overshoot mixing is a significant uncertainty in stellar evolution. Because numerical simulations and turbulent convection models predict exponentially decreasing radial rms turbulent velocity, a popular treatment of the overshoot mixing is to apply a diffusion process with exponentially decreasing diffusion coefficient. It is important to investigate the parameters of the diffusion coefficient because they determine the efficiency of the mixing in the overshoot region. In this paper, we have investigated the effects of the core overshoot mixing on the properties of the core in solar models and have constrained the parameters of the overshoot model by using helioseismic inferences and the observation of the solar 8B neutrino flux. For solar-mass stars, the core overshoot mixing helps to prolong the lifetime of the convective core developed at the ZAMS. If the strength of the mixing is sufficiently high, the convective core in a solar model could survive till the present solar age, leading to large deviations of the sound-speed and density profiles comparing with the helioseismic inferences. The 8B neutrino flux also favours a radiative solar core. Those provide a constraint on the parameters of the exponential diffusion model of the convective overshoot mixing. A limited asteroseismic investigation of 13 Kepler low-mass stars with 1.0 © 2022, CC BY.

关键词： Mixing

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：