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Probing diversity of type II supernovae with the Chinese Space Station Telescope

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arXiv 2024年

作者： Lin, Han Zhang, Jujia Zhang, Xinghan Yunnan Observatories Chinese Academy of Science Kunming650216 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Science Kunming650216 China School of Physics and Information Engineering Jiangsu Second Normal University Jiangsu Nanjing211200 China

Type II supernovae (SNe II), which show abundant hydrogen in their spectra, belong to a class of SNe with diverse observed properties. It is commonly accepted that SNe II are produced by core collapse and explosion of massive stars. However, the large photometric and spectroscopic diversity of SNe II, and the mechanisms responsible for these diversities, have not been thoroughly understood. In this review, we first briefly introduce the optical characteristics and possible progenitors of each subtype of SNe II. We then highlight the role of the Chinese Space Station Telescope in future SN studies. With a deep limiting magnitude, the main survey project could detect SN IIP-like objects as distant as z ∼ 1.2, and obtain UV-optical follow-up for peculiar transients, especially those long-lived events. With a high resolution and a large field of view, the main survey camera is powerful in linking a nearby SN with its progenitor, while the integral field spectrograph is powerful in revealing the SN environment. All this information has the potential to help enrich our understanding of supernova physics. Copyright © 2024, The Authors. All rights reserved.

关键词： Space stations

Long-term double synchronization in close-in gas giant planets

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arXiv 2024年

作者： Guo, Shuaishuai Guo, Jianheng Su, Jie Yan, Dongdong Yunnan Observatories Chinese Academy of Sciences P.O. Box 110 Kunming650011 China School of Astronomy and Space Science University of Chinese Academy of Sciences Beijing China Key Laboratory for the Structure and Evolution of Celestial Objects CAS Kunming650011 China

Hot Jupiters, orbiting their host stars at extremely close distances, undergo tidal evolution, with some being engulfed by their stars due to angular momentum exchanges induced by tidal forces. However, achieving double synchronization can prolong their survival. Using the MESA stellar evolution code, combined with the magnetic braking model of Matt et al. (2015), we calculate 25,000 models with different metallicity and study how to attain the conditions that trigger the long-term double synchronization. Our results indicate that massive planets orbiting stars with lower convective turnover time are easier to achieve long-term double synchronization. The rotation angular velocity at the equilibrium point (Ωsta) is almost equal to orbital angular velocity of planet (n) for the majority of the main sequence lifetime if a system has undergone a long-term double synchronization, regardless of their state at this moment. We further compared our results with known parameters of giant planetary systems and found that those systems with larger planetary masses and lower convective turnover time seem to be less sensitive to changes in the tidal quality factor Q'*. We suggest that for systems that fall on the state of Ωsta ≈ n, regardless of their current state, the synchronization will persist for a long time if orbital synchronization occurs at any stage of their evolution. Our results can be applied to estimate whether a system has experienced long-term double synchronization in the past or may experience it in the future. Copyright © 2024, The Authors. All rights reserved.

关键词： Synchronization

THE IMPACT OF TIDAL MIGRATION OF HOT JUPITERS ON THE ROTATION OF SUN-LIKE MAIN-SEQUENCE STARS A PREPRINT

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arXiv 2024年

作者： Guo, Shuai-Shuai Yunnan Observatories Chinese Academy of Sciences P.O. Box 110 Kunming650011 China School of Astronomy and Space Science University of Chinese Academy of Sciences Beijing China Key Laboratory for the Structure and Evolution of Celestial Objects CAS Kunming650011 China

The tidal interactions of planets affect the stellar evolutionary status and the constraint of their physical parameters by gyrochronology. In this work, we incorporate the tidal interaction and magnetic braking of the stellar wind into MESA and calculate a large grid of 25000 models, covering planets with masses of 0.1-13.0MJ with different orbital distances that orbit late-type stars of different metallicities. We also explore the effect of different stellar initial rotations on the tidal interactions. Our results show that in the case of tidal inward migration, the stellar rotation periods are always lower than that of the star without planet before the planet is engulfed and the difference in the rotation period of its host star always increases with time. After the planet is engulfed, the stellar rotation periods are still lower than that of star without planet, but the difference of periods can be quickly eliminated if the star has a thick convective envelope(smaller mass and larger metallicity), regardless of the mass of the planet and the initial rotation period of the star. In the case of stars with thinner convective envelopes(larger mass and smaller metallicity), the stars will be spined up and remain the faster rotation in a long time. Meanwhile, the planet is easily swallowed and the period differences are large if the initial rotation period of its host star is higher. Final, we also study the evolution of WASP-19 and estimate the range of tidal quality parameter Q'*= (4.6 ± 0.9) × 106 and initial semi-major axis as (0.035 ± 0.004) au. © 2024, CC BY.

关键词： Planets

Properties of the optical component stars in X-ray binary systems

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arXiv 2023年

作者： Zhang, Jia Qian, Sheng-Bang Zhang, Guo-Bao Zhou, Xiao Yunnan Observatories Chinese Academy of Sciences Kunming650216 China Department of Astronomy Key Laboratory of Astroparticle Physics of Yunnan Province Yunnan University Kunming650091 China Key Laboratory of the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming650216 China

We collected a total of 4,058 X-ray binary stars, out of which 339 stars had three atmospheric parameters for optical companions from Gaia and LAMOST, while 264 stars had masses and radii of optical companions determined using stellar evolution models. We conducted a thorough discussion on the reliability of each parameter. The statistical analysis revealed a noticeable bimodal distribution in the mass, radius, and age of the optical components. Our findings led to the proposal of a new quantitative classification criterion for X-ray binary stars. In this classification, one type is categorized as high-mass, high-temperature, and young, while the other type is classified as low-mass, low-temperature, and old, corresponding to High-Mass X-Ray Binaries (HMXBs) and Low-Mass X-Ray Binaries (LMXBs), respectively. The dividing lines were established at 11,500 K, 1.7 M☉, and 0.14 Gyr. The classification results of the three parameters showed consistency with one another in 90% of the cases and were in agreement with previous classifications in 80% of the cases. We found that the parameters of the two types had well-defined boundaries and distinct patterns. Based on our findings, we suggest that temperature is the best parameter for classification. Therefore, we propose that X-ray binary stars should be classified into high-temperature X-ray binaries (HTXBs) and low-temperature X-ray binaries (LTXBs). We believe that this classification is more convenient in practice and aligns well with physics. Copyright © 2023, The Authors. All rights reserved.

关键词： Stars

The possible equation of state of dark matter in low surface brightness galaxies

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Chinese Physics C 2021年第10期45卷 109-116页

作者： Xiaobo Gong Meirong Tang Zhaoyi Xu Yunnan Observatories Chinese Academy of SciencesKunming650216China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of SciencesKunming 650216China Center for Astronomical Mega-Science Chinese Academy of SciencesBeijing 100012China University of Chinese Academy of Sciences Beijing 100049China Key Laboratory of Particle Astrophysics Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China

The observed rotation curves of low surface brightness(LSB)galaxies play an essential role in studying dark matter,and indicate the existence of a central constant density dark matter ***,the cosmological N-body simulations of cold dark matter predict an inner cusped halo with a power-law mass density distribution,and cannot reproduce a central constant-density *** phenomenon is called cusp-core *** dark matter is quiescent and satisfies the condition for hydrostatic equilibrium,the equation of state can be adopted to obtain the density profile in the static and spherically symmetric *** address the cusp-core problem,we assume that the equation of state is independent of the scaling *** lower order approximation for this type of equation of state can naturally lead to a special case,i.e.,■,where p andρrepresent the pressure and density,respectively,V_(rot) depicts the rotation velocity of galaxy,andζandεare positive *** can obtain a density profile that is similar to the pseudo-isothermal halo model whenεis approximately *** obtain a more universally used model,let the equation of state include the polytropic model,i.e.■,from which we can obtain other types of density profiles,such as the profile that is nearly same as the Burkert profile,where s and ρ_(0) are positive constants.

关键词： galaxy dark matter-galaxy rotation curves

The Red Supergiant Progenitor of the Type II Supernova 2024abfl

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arXiv 2024年

作者： Luo, Jingxiao Zhang, Lifu Chen, Bing-Qiu Cheng, Qiyuan Guo, Boyang Li, Jiao Guo, Yanjun Xiong, Jianping Meng, Xiangcun Chen, Xuefei Liu, Zhengwei Han, Zhanwen Kunming650216 China University of Chinese Academy of Sciences Beijing100049 China International Centre of Supernovae Yunnan Key Laboratory Kunming650216 China South-Western Institute for Astronomy Research Yunnan University Kunming650500 China Key Laboratory for the Structure and Evolution of Celestial Objects CAS Kunming650216 China

Linkage between core-collapse supernovae (SNe) and their progenitors is not fully understood and ongoing effort of searching and identifying the progenitors is needed. SN 2024abfl is a recent Type II supernova exploded in the nearby star-bursting galaxy NGC 2146, which is also the host galaxy of SN 2018zd. From archival Hubble Space Telescope (HST) data, we have found a red source (mF814W ∼ 25) near the location (angular distance ≤ 0.2") of SN 2024abfl before its explosion. With F814W and F606W photometry, we found that the properties of this source matched a typical red supergiant (RSG) moderately reddened by interstellar dust at the distance of the host galaxy. We conclude that the SN 2024abfl had an RSG progenitor with initial mass of 10M☉–16 M☉ © 2024, CC BY-NC-SA.

关键词： Supernovae

Adiabatic Mass Loss In Binary Stars. IV. Low and Intermediate Mass Helium Binary Stars

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arXiv 2024年

作者： Zhang, Lifu Ge, Hongwei Chen, Xuefei Han, Zhanwen Yunnan Observatories Chinese Academy of Sciences Kunming650216 China University of Chinese Academy of Sciences Beijing100049 China Key Laboratory for Structure and Evolution of Celestial Objects Chinese Academy of Sciences P.O. Box 110 Kunming650216 China International Centre of Supernovae Yunnan Key Laboratory Kunming650216 China

The unstable mass transfer situation in binary systems will asymptotically cause the adiabatic expansion of the donor star and finally lead to the common envelope phase. This process could happen in helium binary systems once the helium donor star fills its Roche-lobe. We have calculated the adiabatic mass loss model of naked helium stars with a mass range of 0.35 M☉ to 10 M☉, and every mass sequence evolved from the He-ZAMS to the cooling track of white dwarf or carbon ignition. In consideration of the influence of stellar wind, massive helium stars are not considered in this paper. Comparing stellar radius with the evolution of the Roche-lobe under the assumption of conservative mass transfer, we give the critical mass ratio qcrit = MHe/Maccretor as the binary stability criteria of low and intermediate-mass helium binary stars. On He-MS, the result shows 1.0 crit crit = 3. After early He-HG, the qcrit quickly increases even larger than 10 (more stable compared with widely used result qcrit = 4), which is dominated by the expansion of radiative envelope. Our result could be useful for these quick mass transfer binary systems such as AM CVns, UCXBs, and helium novae, and it could guide the binary population synthesis for the formation of special objects such as SNe Ia and GW sources. Copyright © 2024, The Authors. All rights reserved.

关键词： Helium

Red Asymmetry of Hα Line Profiles during the flares on the active RS CVn-type star II Pegasi

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arXiv 2024年

作者： Cao, Dongtao Gu, Shenghong Yunnan Observatories Chinese Academy of Sciences Kunming650216 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming650216 China International Centre of Supernovae Yunnan Key Laboratory Kunming650216 China School of Astronomy and Space Science University of Chinese Academy of Sciences Beijing101408 China

Stellar coronal mass ejections (CMEs) have recently attracted much attention for their impacts on stellar evolution and surrounding exoplanets. RS CVn-type stars could produce large flares, and therefore may have frequent CMEs. Here we report the capture of a possible CME or chromospheric condensation on the RS CVn-type star II Pegasi (II Peg) using high-resolution spectroscopic observation. Two flares were detected during the observation, and the low limits of the flare energies are of the order of 1033 erg and 1034 erg, respectively. Using mean spectrum subtraction, the Hα residual shows red asymmetry during the flares, and the redshifted broad emission components are probably caused by chromospheric condensation or coronal rain. Moreover, a far redshifted extra emission component with a high bulk velocity of 429 km s−1 was observed during the second flare and is probably due to a prominence eruption. The velocity greatly exceeds the star’s escape velocity, which means that this eruption can develop into a CME. The CME mass is estimated to be 0.83–1.48 × 1020 g, which is slightly larger than the value expected from solar flare-CME extrapolation. The kinetic energy of CME, derived to be 0.76–1.15 × 1035 erg, is less than the kinetic energy extrapolated from solar events. Additionally, we could not completely rule out the possibility of chromospheric condensation resulting in the far redshifted extra emission. Finally, there is a blueshifted broad component in the subtracted Hα profile derived using synthesized spectral subtraction when no flare happened, and its behavior is associated with the Hα activity features. Copyright © 2024, The Authors. All rights reserved.

关键词： Condensation

Multiband Simultaneous Photometry of Type II SN 2023ixf with Mephisto and the Twin 50-cm Telescopes

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arXiv 2024年

作者： Yang, Yuan-Pei Liu, Xiangkun Pan, Yu Er, Xinzhong Liu, Dezi Fang, Yuan Du, Guowang Cai, Yongzhi Xu, Xian Chen, Xinlei Zou, Xingzhu Guo, Helong Liu, Chenxu Cheng, Yehao Kumar, Brajesh Liu, Xiaowei South-Western Institute for Astronomy Research Yunnan University Yunnan Kunming650504 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 International Centre of Supernovae Yunnan Key Laboratory Kunming650216 China

SN 2023ixf, recently reported in the nearby galaxy M101 at a distance of 6.85 Mpc, was one of the closest and brightest core-collapse supernovae (CCSNe) in the last decade. In this work, we present multi-wavelength photometric observation of SN 2023ixf with the Multi-channel Photometric Survey Telescope (Mephisto) in uvgr bands and with the twin 50-cm telescopes in griz bands. We find that the bolometric luminosity reached the maximum value of 3 × 1043 erg s−1 at 3.9 days after the explosion and fully settled onto the radioactive tail at ~ 90 days. The effective temperature decreased from 3.2 × 104 K at the first observation and approached to a constant of ~ (3000 − 4000) K after the first two months. The evolution of the photospheric radius is consistent with a homologous expansion with a velocity of 8700 km s−1 in the first two months, and it shrunk subsequently. Based on the radioactive tail, the initial nickel mass is about MNi ~ 0.098M☉. The explosion energy and the ejecta mass are estimated to be E (1.0 − 5.7) × 1051 erg and Mej (3.8 − 16)M☉, respectively. The peak bolometric luminosity is proposed to be contributed by the interaction between the ejecta and the circumstellar medium (CSM). We find a shocked CSM mass of MCSM ~ 0.013M☉, a CSM density of ρCSM ~ 2.5 × 10−13 g cm−3 and a mass loss rate of the progenitor of M ~ 0.022M☉ yr−1 © 2024, CC BY.

关键词： Supernovae