The formation and evolution of binary stars are key steps in star formation and evolution,and thus their research has become the core content of modern astronomical research.Although as early as 1976,Bodan Pachenski p...The formation and evolution of binary stars are key steps in star formation and evolution,and thus their research has become the core content of modern astronomical research.Although as early as 1976,Bodan Pachenski proposed the theory of the evolution of shared envelopes in binary stars,but it was never confirmed until 2022 when the Yunnan Astronomical Observatory of the Chinese Academy of Sciences and an Australian team first observed the phenomenon of shared envelope ejection in binary stars,which provided support for Bodan Pachenski’s theory,but the true formation mechanism and evolution process of binary stars remain undetermined.For this reason,the author of this paper has proposed a theory of the formation and evolution of binary stars based on the theory of the evolution of common envelopes in binary stars and the theory of tidal disruption events,laying a foundation for establishing a complete theory of star formation and evolution.展开更多
2021年7月,世界卫生组织指南实施与知识转化合作中心联合中华医学会杂志社共同创建了旨在提升中国指南和共识质量的专项工作组——指南科学性、透明性和适用性评级(Scientific,Transparent and Applicable Rankings,STAR)工作组,负责组...2021年7月,世界卫生组织指南实施与知识转化合作中心联合中华医学会杂志社共同创建了旨在提升中国指南和共识质量的专项工作组——指南科学性、透明性和适用性评级(Scientific,Transparent and Applicable Rankings,STAR)工作组,负责组织、协调和培训全国医学领域专家完成每年度指南和共识的综合评价工作。展开更多
2021年7月,世界卫生组织指南实施与知识转化合作中心联合中华医学会杂志社共同创建了旨在提升中国指南和共识质量的专项工作组———指南科学性、透明性和适用性评级(Scientific,Transparent and Applicable Rankings,STAR)工作组,负责...2021年7月,世界卫生组织指南实施与知识转化合作中心联合中华医学会杂志社共同创建了旨在提升中国指南和共识质量的专项工作组———指南科学性、透明性和适用性评级(Scientific,Transparent and Applicable Rankings,STAR)工作组,负责组织、协调和培训全国医学领域专家完成每年度指南和共识的综合评价工作。展开更多
The final and award ceremony of the International Standardization Youth Star Competition 2025 were held in Qingdao on November 22-23.The competition attracted 236 teams nationwide who demonstrated great enthusiasm for...The final and award ceremony of the International Standardization Youth Star Competition 2025 were held in Qingdao on November 22-23.The competition attracted 236 teams nationwide who demonstrated great enthusiasm for participating in the standardization undertaking.The competition followed the mode of“the industry puts forward questions,and the academia provides solutions”.Shandong Port Group Co.,Ltd.,Contemporary Amperex Technology Co.,Ltd.(CATL),Huawei Technologies Co.,Ltd.,and Beijing Zhongbiaolvjian Engineering Design and Research Institute Co.,Ltd.set up themed tracks respectively,and competitors developed standard proposals for the corresponding themes.展开更多
In this paper,we review recent highlights in heavy-ion collisions and proton–proton collisions at top energies from STAR experiment at the Relativistic Heavy Ion Collider(RHIC) with key contributions from Chinese gro...In this paper,we review recent highlights in heavy-ion collisions and proton–proton collisions at top energies from STAR experiment at the Relativistic Heavy Ion Collider(RHIC) with key contributions from Chinese groups,including the quark–gluon plasma bulk properties,electromagnetic probes,heavy flavor and jets,antimatter hyper-nucleus,nuclear structure,global polarization,and nucleon spin structure.These data serve as important ingredients in the physics of quantum chromodynamics.展开更多
This paper yields a new exact solution for dense stellar objects by employing the Einstein-Maxwell system of differential equations.The established model comprises three interior layers with distinguishable equations ...This paper yields a new exact solution for dense stellar objects by employing the Einstein-Maxwell system of differential equations.The established model comprises three interior layers with distinguishable equations of state(EoSs):the polytropic EoS at the core layer,the quadratic EoS at the intermediate layer and the modified Van der Waals EoS at the envelope layer.The physical features indicate that the matter variables,metric functions and other physical conditions are viable with dense astrophysical objects.Excitingly,this model is an extension solution of the two-layered model generated by Sunzu and Lighuda.The layers are matched gently across the junctions with the care of the Reissner-Nordström exterior spacetime.Utilizing our model,star masses and radii compatible with observations and satisfactorily known objects are generated.The findings from this paper may be useful to describes purported strange stars such as SAX J1808.4-3658 and binary stars such as Vela X-1.展开更多
The subsurface convective zones (CZs) of massive stars significantly influence many of their key characteristics.Previous studies have paid little attention to the impact of rotation on the subsurface CZ,so we aim to ...The subsurface convective zones (CZs) of massive stars significantly influence many of their key characteristics.Previous studies have paid little attention to the impact of rotation on the subsurface CZ,so we aim to investigate the evolution of this zone in rapidly rotating massive stars.We use the Modules for Experiments in Stellar Astrophysics to simulate the subsurface CZs of massive stars during the main sequence phase.We establish stellar models with initial masses ranging from 5 M⊙to 120 M⊙,incorporating four metallicities (Z=0.02,0.006,0.002,and 0.0001) and three rotational velocities (ω/ωcrit=0,ω/ωcrit=0.50,andω/ωcrit=0.75).We find that rapid rotation leads to an expansion of the subsurface CZ,increases convective velocities,and promotes the development of this zone.Additionally,subsurface CZs can also emerge in stars with lower metallicities.Comparing our models with observations of massive stars in the Galaxy,the Large Magellanic Cloud,and the Small Magellanic Cloud,we find that rotating models better encompass the observed samples.Rotation significantly influences the evolution of the subsurface CZ in massive stars.By comparing with the observed microturbulence on the surfaces of OB stars,we propose that the subsurface CZs may be one of the sources of microturbulence.展开更多
Daytime star images captured by dedicated near-space star sensors are characterized by short exposures,high noise,and low Signal-to-Noise Ratios(SNRs).Such imaging is also affected by atmospheric turbulence,causing op...Daytime star images captured by dedicated near-space star sensors are characterized by short exposures,high noise,and low Signal-to-Noise Ratios(SNRs).Such imaging is also affected by atmospheric turbulence,causing optical phenomena,such as scintillation,distortion,and jitter.This causes difficulty in recording high-precision star images during the daytime.This study proposes an adaptive star point extraction method based on dynamically predicting stars'positions.First,it predicts the approximate position of stars based on the star catalog,sensor attitude,observation time,and other information,improving the extraction accuracy.Second,it employs a regional SNR sorting method that adaptively selects star images with higher SNRs,suppressing the scintillation effect and enhancing the SNR of star images.Third,depending on the star's motion trajectory characteristics on the image plane,it utilizes the centroid smoothing method for extraction,thus overcoming the impact of star drift.Field experiments demonstrate that the proposed method can effectively overcome star scintillation,drift,and irregular imaging caused by atmospheric turbulence,achieving a 100%success rate.Moreover,the extraction accuracy improves by more than 80%compared to traditional adaptive methods,attaining a value of 0.05 pixels(0.5"),thereby meeting the requirements of daytime astronomical attitude determination and positioning.展开更多
The best way to check the validity of our theories(models)is by direct comparison with the experiment(observations).However,this process suffers from numerical inaccuracies,which are not frequently studied and often r...The best way to check the validity of our theories(models)is by direct comparison with the experiment(observations).However,this process suffers from numerical inaccuracies,which are not frequently studied and often remain mostly unknown.In this study,we focus on addressing the numerical inaccuracies intrinsic to the process of comparing theory and observations.To achieve this goal,we built four-dimensional(4D)spectral grids for Wolf–Rayet stars(WC and WN spectral classes)and blue supergiants characterized by low metallicity similar to that of the Small Magellanic Cloud.In contrast to lighter(three-dimensional)grids,which rely on a priori assumptions about certain stellar parameters(e.g.,wind velocity)and thus have limited applicability,our 4D grids vary four independent parameters,enabling more flexible and broadly applicable spectral fitting.Utilizing these 4D grids,we developed and validated a fitting approach facilitating direct fits to observed spectra.Through rigorous testing on designated“test”models,we demonstrated that the numerical precision of derived essential stellar parameters,including effective temperature,mass-loss rate,luminosity,and wind velocity,is better than 0.05 dex.Furthermore,we explored the influence of unaccounted factors,including variations in the metal abundances,wind acceleration laws,and clumping,on the precision of the derived parameters.The results indicate that the first two factors have the strongest influence on the numerical accuracy of the derived stellar parameters.Variations in abundances predominantly influenced the mass-loss rate for weak-wind scenarios,while effective temperature and luminosity remained robust.We found that the wind acceleration law influences the numerical uncertainty of the derived wind parameters mostly for models with weak winds.Interestingly,different degrees of clumping demonstrated good precision for spectra with strong winds,contrasting with a decrease in the precision for weak-wind cases.We found also that the accuracy of our approach depends on spectral range and the inclusion of ultraviolet spectral range improves the precision of derived parameters,especially for an object with weak winds.展开更多
Binary systems in the asymptotic giant branch(AGB)phase are widely recognized as a leading theoretical framework underpinning the observed asymmetric morphologies of planetary nebulae.However,the detection of binary c...Binary systems in the asymptotic giant branch(AGB)phase are widely recognized as a leading theoretical framework underpinning the observed asymmetric morphologies of planetary nebulae.However,the detection of binary companions in AGB systems is severely hampered by the overwhelming brightness and variability of the evolved primary star,which dominates the photometric and spectroscopic signatures.Ultraviolet(UV)excess emission has been proposed as a candidate diagnostic for the presence of binary companions in AGB systems.This paper evaluates the Chinese Space Station Telescope’s(CSST)ability to detect UV excess emission in AGB stars,leveraging its unprecedented UV sensitivity and wide-feld survey capabilities.We employed synthetic spectral libraries of M0–M8 type giants for primary stars and the ATLAS 9 atmospheric model grid for companion stars spanning a temperature range of 6500 to 12,000 K.By convolving these model spectra with the CSST multi-band flter system,we computed color–color diagrams(g–y versus NUV–u)to construct a diagnostic grid.This grid incorporates interstellar extinction corrections and establishes a framework for identifying AGB binary candidates through direct comparison between observed photometry and theoretical predictions.Furthermore,we discuss the physical origins of UV excess in AGB stars.This study pioneers a diagnostic framework leveraging CSST’s unique multi-band UV-visible synergy to construct color–color grids for binary candidate identifcation,overcoming limitations of non-simultaneous multi-instrument observations.展开更多
We identify a point-symmetric morphology of three pairs of ears/clumps in the core-collapse supernova remnant(CCSNR)Puppis A,supporting the jittering jets explosion mechanism(JJEM).In the JJEM,the three pairs of jets ...We identify a point-symmetric morphology of three pairs of ears/clumps in the core-collapse supernova remnant(CCSNR)Puppis A,supporting the jittering jets explosion mechanism(JJEM).In the JJEM,the three pairs of jets that shaped the three pairs of ears/clumps in Puppis A are part of a large set,about 10–30 pairs of jets,that exploded Puppis A.Some similarities in morphological features between CCSNR Puppis A and three multipolar planetary nebulae considered to have been shaped by jets solidify the claim for shaping by jets.Puppis A has a prominent dipole structure,where one side is bright with a well-defined boundary,while the other is faint and defused.The neutron star(NS)has a natal kick velocity in the opposite direction to the denser part of the dipole structure.We propose a new mechanism in the frame of the JJEM that imparts a natal kick to the NS,the kick-byearly asymmetrical pair(kick-BEAP)mechanism.At the early phase of the explosion process,the NS launches a pair of jets where one jet is much more energetic than the counter jet.The more energetic jet compresses a dense side to the CCSNR,and,by momentum conservation,the NS recoils in the opposite direction.Our study supports the JJEM as the primary explosion mechanism of core-collapse supernovae and enriches this explosion mechanism by introducing the novel kick-BEAP mechanism.展开更多
文摘The formation and evolution of binary stars are key steps in star formation and evolution,and thus their research has become the core content of modern astronomical research.Although as early as 1976,Bodan Pachenski proposed the theory of the evolution of shared envelopes in binary stars,but it was never confirmed until 2022 when the Yunnan Astronomical Observatory of the Chinese Academy of Sciences and an Australian team first observed the phenomenon of shared envelope ejection in binary stars,which provided support for Bodan Pachenski’s theory,but the true formation mechanism and evolution process of binary stars remain undetermined.For this reason,the author of this paper has proposed a theory of the formation and evolution of binary stars based on the theory of the evolution of common envelopes in binary stars and the theory of tidal disruption events,laying a foundation for establishing a complete theory of star formation and evolution.
文摘2021年7月,世界卫生组织指南实施与知识转化合作中心联合中华医学会杂志社共同创建了旨在提升中国指南和共识质量的专项工作组——指南科学性、透明性和适用性评级(Scientific,Transparent and Applicable Rankings,STAR)工作组,负责组织、协调和培训全国医学领域专家完成每年度指南和共识的综合评价工作。
文摘2021年7月,世界卫生组织指南实施与知识转化合作中心联合中华医学会杂志社共同创建了旨在提升中国指南和共识质量的专项工作组———指南科学性、透明性和适用性评级(Scientific,Transparent and Applicable Rankings,STAR)工作组,负责组织、协调和培训全国医学领域专家完成每年度指南和共识的综合评价工作。
文摘The final and award ceremony of the International Standardization Youth Star Competition 2025 were held in Qingdao on November 22-23.The competition attracted 236 teams nationwide who demonstrated great enthusiasm for participating in the standardization undertaking.The competition followed the mode of“the industry puts forward questions,and the academia provides solutions”.Shandong Port Group Co.,Ltd.,Contemporary Amperex Technology Co.,Ltd.(CATL),Huawei Technologies Co.,Ltd.,and Beijing Zhongbiaolvjian Engineering Design and Research Institute Co.,Ltd.set up themed tracks respectively,and competitors developed standard proposals for the corresponding themes.
基金supported in part by the National Key Research and Development Program of China (Grant No.2022YFA1604900)the National Natural Science Foundation of China (Grant No.12575145)。
文摘In this paper,we review recent highlights in heavy-ion collisions and proton–proton collisions at top energies from STAR experiment at the Relativistic Heavy Ion Collider(RHIC) with key contributions from Chinese groups,including the quark–gluon plasma bulk properties,electromagnetic probes,heavy flavor and jets,antimatter hyper-nucleus,nuclear structure,global polarization,and nucleon spin structure.These data serve as important ingredients in the physics of quantum chromodynamics.
文摘This paper yields a new exact solution for dense stellar objects by employing the Einstein-Maxwell system of differential equations.The established model comprises three interior layers with distinguishable equations of state(EoSs):the polytropic EoS at the core layer,the quadratic EoS at the intermediate layer and the modified Van der Waals EoS at the envelope layer.The physical features indicate that the matter variables,metric functions and other physical conditions are viable with dense astrophysical objects.Excitingly,this model is an extension solution of the two-layered model generated by Sunzu and Lighuda.The layers are matched gently across the junctions with the care of the Reissner-Nordström exterior spacetime.Utilizing our model,star masses and radii compatible with observations and satisfactorily known objects are generated.The findings from this paper may be useful to describes purported strange stars such as SAX J1808.4-3658 and binary stars such as Vela X-1.
基金the National Natural Science Foundation of China under grant Nos.U2031204,12163005,12373038,12288102,and 12263006the science research grant from the China Manned Space Project with No.CMSCSST-2021-A10+1 种基金the Natural Science Foundation of Xinjiang Nos.2022D01D85 and 2022TSYCLJ0006the Major Science and Technology Program of Xinjiang Uygur Autonomous Region under grant No.2022A03013-3.
文摘The subsurface convective zones (CZs) of massive stars significantly influence many of their key characteristics.Previous studies have paid little attention to the impact of rotation on the subsurface CZ,so we aim to investigate the evolution of this zone in rapidly rotating massive stars.We use the Modules for Experiments in Stellar Astrophysics to simulate the subsurface CZs of massive stars during the main sequence phase.We establish stellar models with initial masses ranging from 5 M⊙to 120 M⊙,incorporating four metallicities (Z=0.02,0.006,0.002,and 0.0001) and three rotational velocities (ω/ωcrit=0,ω/ωcrit=0.50,andω/ωcrit=0.75).We find that rapid rotation leads to an expansion of the subsurface CZ,increases convective velocities,and promotes the development of this zone.Additionally,subsurface CZs can also emerge in stars with lower metallicities.Comparing our models with observations of massive stars in the Galaxy,the Large Magellanic Cloud,and the Small Magellanic Cloud,we find that rotating models better encompass the observed samples.Rotation significantly influences the evolution of the subsurface CZ in massive stars.By comparing with the observed microturbulence on the surfaces of OB stars,we propose that the subsurface CZs may be one of the sources of microturbulence.
基金funded by the National Natural Science Foundation of China(Nos.42374011,42074013)through the Natural Science Foundation’s Outstanding Youth Fund Program of Henan Province,China(Nos.242300421150,242300421151)。
文摘Daytime star images captured by dedicated near-space star sensors are characterized by short exposures,high noise,and low Signal-to-Noise Ratios(SNRs).Such imaging is also affected by atmospheric turbulence,causing optical phenomena,such as scintillation,distortion,and jitter.This causes difficulty in recording high-precision star images during the daytime.This study proposes an adaptive star point extraction method based on dynamically predicting stars'positions.First,it predicts the approximate position of stars based on the star catalog,sensor attitude,observation time,and other information,improving the extraction accuracy.Second,it employs a regional SNR sorting method that adaptively selects star images with higher SNRs,suppressing the scintillation effect and enhancing the SNR of star images.Third,depending on the star's motion trajectory characteristics on the image plane,it utilizes the centroid smoothing method for extraction,thus overcoming the impact of star drift.Field experiments demonstrate that the proposed method can effectively overcome star scintillation,drift,and irregular imaging caused by atmospheric turbulence,achieving a 100%success rate.Moreover,the extraction accuracy improves by more than 80%compared to traditional adaptive methods,attaining a value of 0.05 pixels(0.5"),thereby meeting the requirements of daytime astronomical attitude determination and positioning.
文摘The best way to check the validity of our theories(models)is by direct comparison with the experiment(observations).However,this process suffers from numerical inaccuracies,which are not frequently studied and often remain mostly unknown.In this study,we focus on addressing the numerical inaccuracies intrinsic to the process of comparing theory and observations.To achieve this goal,we built four-dimensional(4D)spectral grids for Wolf–Rayet stars(WC and WN spectral classes)and blue supergiants characterized by low metallicity similar to that of the Small Magellanic Cloud.In contrast to lighter(three-dimensional)grids,which rely on a priori assumptions about certain stellar parameters(e.g.,wind velocity)and thus have limited applicability,our 4D grids vary four independent parameters,enabling more flexible and broadly applicable spectral fitting.Utilizing these 4D grids,we developed and validated a fitting approach facilitating direct fits to observed spectra.Through rigorous testing on designated“test”models,we demonstrated that the numerical precision of derived essential stellar parameters,including effective temperature,mass-loss rate,luminosity,and wind velocity,is better than 0.05 dex.Furthermore,we explored the influence of unaccounted factors,including variations in the metal abundances,wind acceleration laws,and clumping,on the precision of the derived parameters.The results indicate that the first two factors have the strongest influence on the numerical accuracy of the derived stellar parameters.Variations in abundances predominantly influenced the mass-loss rate for weak-wind scenarios,while effective temperature and luminosity remained robust.We found that the wind acceleration law influences the numerical uncertainty of the derived wind parameters mostly for models with weak winds.Interestingly,different degrees of clumping demonstrated good precision for spectra with strong winds,contrasting with a decrease in the precision for weak-wind cases.We found also that the accuracy of our approach depends on spectral range and the inclusion of ultraviolet spectral range improves the precision of derived parameters,especially for an object with weak winds.
基金supports of this work are from the science research grants from the China Manned Space Project(NOs.CMSCSST-2021-A09,CMS-CSST-2021-A10,etc.)the National Natural Science Foundation of China(NSFC,Nos.12473027 and 12333005)the Guangdong Basic and Applied Basic Research Funding(No.2024A1515010798).
文摘Binary systems in the asymptotic giant branch(AGB)phase are widely recognized as a leading theoretical framework underpinning the observed asymmetric morphologies of planetary nebulae.However,the detection of binary companions in AGB systems is severely hampered by the overwhelming brightness and variability of the evolved primary star,which dominates the photometric and spectroscopic signatures.Ultraviolet(UV)excess emission has been proposed as a candidate diagnostic for the presence of binary companions in AGB systems.This paper evaluates the Chinese Space Station Telescope’s(CSST)ability to detect UV excess emission in AGB stars,leveraging its unprecedented UV sensitivity and wide-feld survey capabilities.We employed synthetic spectral libraries of M0–M8 type giants for primary stars and the ATLAS 9 atmospheric model grid for companion stars spanning a temperature range of 6500 to 12,000 K.By convolving these model spectra with the CSST multi-band flter system,we computed color–color diagrams(g–y versus NUV–u)to construct a diagnostic grid.This grid incorporates interstellar extinction corrections and establishes a framework for identifying AGB binary candidates through direct comparison between observed photometry and theoretical predictions.Furthermore,we discuss the physical origins of UV excess in AGB stars.This study pioneers a diagnostic framework leveraging CSST’s unique multi-band UV-visible synergy to construct color–color grids for binary candidate identifcation,overcoming limitations of non-simultaneous multi-instrument observations.
基金A grant from the Pazy Foundation supported this research。
文摘We identify a point-symmetric morphology of three pairs of ears/clumps in the core-collapse supernova remnant(CCSNR)Puppis A,supporting the jittering jets explosion mechanism(JJEM).In the JJEM,the three pairs of jets that shaped the three pairs of ears/clumps in Puppis A are part of a large set,about 10–30 pairs of jets,that exploded Puppis A.Some similarities in morphological features between CCSNR Puppis A and three multipolar planetary nebulae considered to have been shaped by jets solidify the claim for shaping by jets.Puppis A has a prominent dipole structure,where one side is bright with a well-defined boundary,while the other is faint and defused.The neutron star(NS)has a natal kick velocity in the opposite direction to the denser part of the dipole structure.We propose a new mechanism in the frame of the JJEM that imparts a natal kick to the NS,the kick-byearly asymmetrical pair(kick-BEAP)mechanism.At the early phase of the explosion process,the NS launches a pair of jets where one jet is much more energetic than the counter jet.The more energetic jet compresses a dense side to the CCSNR,and,by momentum conservation,the NS recoils in the opposite direction.Our study supports the JJEM as the primary explosion mechanism of core-collapse supernovae and enriches this explosion mechanism by introducing the novel kick-BEAP mechanism.
