Spiral galaxies are the most common type of galaxies in the universe,and most spiral galaxies contain a supermassive black hole in their center.However,thus far,the formation of spiral galaxies is still not fully unde...Spiral galaxies are the most common type of galaxies in the universe,and most spiral galaxies contain a supermassive black hole in their center.However,thus far,the formation of spiral galaxies is still not fully understood,and especially,what determines the number of spiral arms is still an open question as well.Here,inspired by fascinating spiral galaxies,we demonstrate that such a spiral-galaxy-shaped optical field can be generated by interference of a vortex wave and a trumpet wave.Interestingly,we show it is the topological charge of the vortex wave that determines the number of spiral arms in our model.展开更多
In this paper,new light curve fitting and orbital period change analysis of two contact binaries NSVS 9023048 and NSVS 2461789 are presented.We found that both of them are totally eclipsing contact binaries.Our photom...In this paper,new light curve fitting and orbital period change analysis of two contact binaries NSVS 9023048 and NSVS 2461789 are presented.We found that both of them are totally eclipsing contact binaries.Our photometric solutions suggest that NSVS 9023048 is a deep contact binary(q=10.14,f=69.2%),however,NSVS 2461789is a shallow one(f=24.4%,q=3.08).The asymmetric light curves of NSVS 2461789 and NSVS 9023048 can be explained by the star-spot activity.At the same time,using the available eclipse times,we first studied the orbital period changes of these two targets.It is discovered that the period of NSVS 9023048 is decreasing at a rate of dP/dt=-1.17×10^(-6)day yr^(-1),which can be explained by mass transfer from the more massive star to the less massive one or angular momentum loss.In addition,the O-C diagrams of NSVS 9023048 and NSVS 2461789show possible cyclic oscillations with a period of 7.29 yr and 9.91 yr,respectively.The cyclic oscillations may be caused by the light-travel time effect due to the presence of a third component.The mass of the tertiary companion is determined to be M_(3)sin(i_(3))=9.05 Mefor NSVS 9023048 and M_(3)sin(i_(3))=0.11 Mefor NSVS 2461789.Based on our calculations,the third body of NSVS 9023048 may be a black hole candidate.Our study also reveals that NSVS 9023048 is stable now.展开更多
In the current paper,we present a study of the spatial distribution of luminous blue variables(LBVs)and various LBV candidates(c LBVs)with respect to OB associations in the galaxy M33.The identification of blue star g...In the current paper,we present a study of the spatial distribution of luminous blue variables(LBVs)and various LBV candidates(c LBVs)with respect to OB associations in the galaxy M33.The identification of blue star groups was based on the LGGS data and was carried out by two clustering algorithms with initial parameters determined during simulations of random stellar fields.We have found that the distribution of distances to the nearest OB association obtained for the LBV/c LBV sample is close to that for massive stars with Minit>20 M⊙and WolfRayet stars.This result is in good agreement with the standard assumption that LBVs represent an intermediate stage in the evolution of the most massive stars.However,some objects from the LBV/cLBV sample,particularly Fe II-emission stars,demonstrated severe isolation compared to other massive stars,which,together with certain features of their spectra,implicitly indicates that the nature of these objects and other LBVs/cLBVs may differ radically.展开更多
AR Aur A+B is a close binary of astrophysical interest because dissimilar surface compositions are reported between similar late B-type dwarfs.A new spectroscopic study on this system was carried out based on the dise...AR Aur A+B is a close binary of astrophysical interest because dissimilar surface compositions are reported between similar late B-type dwarfs.A new spectroscopic study on this system was carried out based on the disentangled spectra,in order to determine their atmospheric parameters and elemental abundances.The effective temperature and microturbulence(determined from the equivalent widths of Fe II lines)turned out to be(11,150 K,0.9 km s^(-1))and(10,650 K,0.1 km s^(-1))for A and B,respectively.The chemical abundances of 28 elements were then derived while taking into account the non-LTE effect for Z≤15 elements(Z:atomic number).The following trends were elucidated for[X/H](abundance of X relative to the Sun):(1)Qualitatively,[X/H]shows a rough global tendency to increase with Z,with the gradient steeper for A than for B.(2)However,considerable dispersion is involved for A,since prominently large peculiarities are seen in specific elements reflecting the characteristics of HgMn stars(e.g.,very deficient N,Al,Sc,Ni;markedly overabundant P,Mn).(3)In contrast,the Z-dependence of[X/H]for B tends to be nearly linear with only a small dispersion.These observational facts may serve as a key to understanding the critical condition for the emergence of the chemical anomaly.展开更多
Galaxy morphology detection is a pivotal task for unraveling cosmic evolutionary mechanisms,yet existing models exhibit insufficient detection accuracy for irregular and small-target galaxies.To address this,this pape...Galaxy morphology detection is a pivotal task for unraveling cosmic evolutionary mechanisms,yet existing models exhibit insufficient detection accuracy for irregular and small-target galaxies.To address this,this paper proposes the STAR-YOLO galaxy morphology detection model.The backbone network incorporates the novel Multi-scale Attentive Context Aggregation module,which deeply integrates multi-scale dilated convolution with a progressive spatial-channel attention mechanism to enhance feature extraction for irregular and small galaxies.Meanwhile,we design the lightweight Lightweight Efficient Attention Network module that reduces parameters through channel compression.The proposed Adaptive Focal Spatial-IoU loss function further improves detection performance for small galaxies through dynamic focal mechanisms and scale-invariant optimization.Evaluated on Galaxy Zoo 2 data set,our STAR-YOLO achieves 96.3%mean average precision—a 2.5%improvement over baseline models,with irregular galaxy recognition accuracy notably increasing by 9.3%.Comparative experiments demonstrate superior detection capabilities for multi-target irregular galaxies compared to stateof-the-art models,providing an innovative solution for astronomical image analysis.展开更多
δScuti(δSct)stars are potential distance tracers for studying the Milky Way structure.We conduct a comprehensive analysis of the period-luminosity(PL)and period-luminosity-metallicity(PLZ)relations forδSct stars,in...δScuti(δSct)stars are potential distance tracers for studying the Milky Way structure.We conduct a comprehensive analysis of the period-luminosity(PL)and period-luminosity-metallicity(PLZ)relations forδSct stars,integrating data from the Zwicky Transient Facility,the Transiting Exoplanet Survey Satellite,Large Sky Area Multi-Object Fiber Spectroscopic Telescope,Apache Point Observatory Galactic Evolution Experiment,and Gaia.To mitigate the impact of the Gaia parallax zero point offset,we applied a correction method,determining the optimal zero point value to be zp(?)=35±2μas.Using the three best bands,by varying the parallax error threshold,we found that the total error of the PLR zero point was minimized to 0.9%at a parallax error threshold of 6%.With this threshold,we derived the PL and PLZ relations for nine bands(from optical to mid-infrared)and five Wesenheit bands.Through our analysis,we conclude that the influence of metallicity on the PLR ofδSct stars is not significant,and the differences across various bands are minimal.展开更多
We presented the first photometric light curve solutions of four W Ursae Majoris-type contact binary systems.This investigation utilized photometric data from the Transiting Exoplanet Survey Satellite and Gaia Data Re...We presented the first photometric light curve solutions of four W Ursae Majoris-type contact binary systems.This investigation utilized photometric data from the Transiting Exoplanet Survey Satellite and Gaia Data Release 3(DR3).We used the PHysics Of Eclipsing BinariEs Python code and the Markov Chain Monte Carlo method for these light curve solutions.Only TIC 249064185 among the target systems needed a cold starspot to be included in the analysis.Based on the estimated mass ratios for these total eclipse systems,three of them are categorized as low mass ratio contact binary stars.The absolute parameters of the systems were estimated using the Gaia DR3 parallax method and the orbital period and semimajor axis(P-a)empirical relationship.We ascertained that the TIC 318015356 and TIC 55522736 systems are A-subtypes,while TIC 249064185 and TIC 397984843 are W-subtypes,depending on each component’s effective temperature and mass.We estimated the initial masses of the stars,the mass lost by the binary system,and the systems’ages.We displayed star positions in the mass-radius,mass-luminosity,and total mass-orbital angular momentum diagrams.In addition,our findings indicate a good agreement with the mass-temperature empirical parameter relationship for the primary stars.展开更多
Sulfur-bearing molecules are frequently detected in star-forming regions.The abundance ratio of SO to SO_(2)(hereafter,SO/SO_(2) ratio)has been proposed as a potential evolutionary tracer of star formation because ten...Sulfur-bearing molecules are frequently detected in star-forming regions.The abundance ratio of SO to SO_(2)(hereafter,SO/SO_(2) ratio)has been proposed as a potential evolutionary tracer of star formation because tentative correlations have been found between SO/SO_(2) ratio and evolutionary stages.Nonetheless,the lack of highresolution observations and extensive statistical analyses of large samples raises questions regarding its efficacy as an evolutionary tracer.In this study,we analyze 31 protostellar cores with both SO and SO_(2) detection to investigate the relationship between the SO/SO_(2) ratio and two evolutionary parameters of chemical richness factor and gas temperatures.The correlations between SO/SO_(2) ratio and evolutionary parameters have been found,but these correlations are mainly contributed by low-mass cores rather than high-mass cores.Our findings suggest that the SO/SO_(2) ratio serves as a reliable evolutionary tracer for low-mass dense cores.In high-mass cores,the relationship between the SO/SO_(2) ratio and evolutionary stage remains ambiguous.This likely arises from both vigorous stellar feedback effects and the potential absence of distinct evolutionary stages analogous to those in low-mass cores.Consequently,higher-resolution observations with expanded statistical samples are required to assess the viability of SO/SO_(2) ratio as an evolutionary tracer for high-mass cores.展开更多
The availability of large data sets containing stellar parameters,distances,and extinctions for stars in the Milky Way,particularly within the Galactic disk,is essential for advancing our understanding of the Galaxy’...The availability of large data sets containing stellar parameters,distances,and extinctions for stars in the Milky Way,particularly within the Galactic disk,is essential for advancing our understanding of the Galaxy’s stellar populations,structure,kinematics,and chemical evolution.In this study,we present a catalog of stellar parameters,including effective temperature (T_(eff)),metallicity ([Fe/H]),absolute magnitudes (M_(G)),distances (d),and reddening values (E(G_(BP)-G_(RP))),for a sample of 141 million stars from the SkyMapper Southern Survey.These parameters are derived using the SPar algorithm,which employs a fitting procedure to match multi-band photometric observations and estimate the stellar properties (T_(eff),[Fe/H],M_(G),d,and E(G_(BP)-G_(RP))) on an individual star basis,following the methodology outlined in our previous work.This study successfully determines stellar parameters and extinction values simultaneously for stars located in high and low Galactic latitudes.The resulting stellar parameters and extinction values are in good agreement with results from other studies,demonstrating the robustness of our method.We derive a temperature dispersion of 195 K and a metallicity dispersion of 0.31 dex when comparing our results with spectroscopic data.The catalog produced in this work provides a valuable resource for future research on the Galactic metallicity distribution function,the structure of the Galaxy,threedimensional extinction mapping,and other related astrophysical topics.展开更多
基金National Natural Science Foundation of China(12174047,12574353)。
文摘Spiral galaxies are the most common type of galaxies in the universe,and most spiral galaxies contain a supermassive black hole in their center.However,thus far,the formation of spiral galaxies is still not fully understood,and especially,what determines the number of spiral arms is still an open question as well.Here,inspired by fascinating spiral galaxies,we demonstrate that such a spiral-galaxy-shaped optical field can be generated by interference of a vortex wave and a trumpet wave.Interestingly,we show it is the topological charge of the vortex wave that determines the number of spiral arms in our model.
基金supported by the National Natural Science Foundation of China(Nos.11988101,U1931101,42364001 and 11933008)the Foundation of Education Bureau of Guizhou Province,China(No.KY(2020)003)+1 种基金the Guizhou Provincial Science and Technology Foundation(No.ZK[2022]322)the Guizhou Normal University 2019Special project of training new academics。
文摘In this paper,new light curve fitting and orbital period change analysis of two contact binaries NSVS 9023048 and NSVS 2461789 are presented.We found that both of them are totally eclipsing contact binaries.Our photometric solutions suggest that NSVS 9023048 is a deep contact binary(q=10.14,f=69.2%),however,NSVS 2461789is a shallow one(f=24.4%,q=3.08).The asymmetric light curves of NSVS 2461789 and NSVS 9023048 can be explained by the star-spot activity.At the same time,using the available eclipse times,we first studied the orbital period changes of these two targets.It is discovered that the period of NSVS 9023048 is decreasing at a rate of dP/dt=-1.17×10^(-6)day yr^(-1),which can be explained by mass transfer from the more massive star to the less massive one or angular momentum loss.In addition,the O-C diagrams of NSVS 9023048 and NSVS 2461789show possible cyclic oscillations with a period of 7.29 yr and 9.91 yr,respectively.The cyclic oscillations may be caused by the light-travel time effect due to the presence of a third component.The mass of the tertiary companion is determined to be M_(3)sin(i_(3))=9.05 Mefor NSVS 9023048 and M_(3)sin(i_(3))=0.11 Mefor NSVS 2461789.Based on our calculations,the third body of NSVS 9023048 may be a black hole candidate.Our study also reveals that NSVS 9023048 is stable now.
文摘In the current paper,we present a study of the spatial distribution of luminous blue variables(LBVs)and various LBV candidates(c LBVs)with respect to OB associations in the galaxy M33.The identification of blue star groups was based on the LGGS data and was carried out by two clustering algorithms with initial parameters determined during simulations of random stellar fields.We have found that the distribution of distances to the nearest OB association obtained for the LBV/c LBV sample is close to that for massive stars with Minit>20 M⊙and WolfRayet stars.This result is in good agreement with the standard assumption that LBVs represent an intermediate stage in the evolution of the most massive stars.However,some objects from the LBV/cLBV sample,particularly Fe II-emission stars,demonstrated severe isolation compared to other massive stars,which,together with certain features of their spectra,implicitly indicates that the nature of these objects and other LBVs/cLBVs may differ radically.
文摘AR Aur A+B is a close binary of astrophysical interest because dissimilar surface compositions are reported between similar late B-type dwarfs.A new spectroscopic study on this system was carried out based on the disentangled spectra,in order to determine their atmospheric parameters and elemental abundances.The effective temperature and microturbulence(determined from the equivalent widths of Fe II lines)turned out to be(11,150 K,0.9 km s^(-1))and(10,650 K,0.1 km s^(-1))for A and B,respectively.The chemical abundances of 28 elements were then derived while taking into account the non-LTE effect for Z≤15 elements(Z:atomic number).The following trends were elucidated for[X/H](abundance of X relative to the Sun):(1)Qualitatively,[X/H]shows a rough global tendency to increase with Z,with the gradient steeper for A than for B.(2)However,considerable dispersion is involved for A,since prominently large peculiarities are seen in specific elements reflecting the characteristics of HgMn stars(e.g.,very deficient N,Al,Sc,Ni;markedly overabundant P,Mn).(3)In contrast,the Z-dependence of[X/H]for B tends to be nearly linear with only a small dispersion.These observational facts may serve as a key to understanding the critical condition for the emergence of the chemical anomaly.
文摘Galaxy morphology detection is a pivotal task for unraveling cosmic evolutionary mechanisms,yet existing models exhibit insufficient detection accuracy for irregular and small-target galaxies.To address this,this paper proposes the STAR-YOLO galaxy morphology detection model.The backbone network incorporates the novel Multi-scale Attentive Context Aggregation module,which deeply integrates multi-scale dilated convolution with a progressive spatial-channel attention mechanism to enhance feature extraction for irregular and small galaxies.Meanwhile,we design the lightweight Lightweight Efficient Attention Network module that reduces parameters through channel compression.The proposed Adaptive Focal Spatial-IoU loss function further improves detection performance for small galaxies through dynamic focal mechanisms and scale-invariant optimization.Evaluated on Galaxy Zoo 2 data set,our STAR-YOLO achieves 96.3%mean average precision—a 2.5%improvement over baseline models,with irregular galaxy recognition accuracy notably increasing by 9.3%.Comparative experiments demonstrate superior detection capabilities for multi-target irregular galaxies compared to stateof-the-art models,providing an innovative solution for astronomical image analysis.
基金supported by the National Natural Science Foundation of China(NSFC)through grants 12173047,12373035,12322306,12373028,12233009 and 12133002X.C.and S.W.acknowledge supports from the Youth Innovation Promotion Association of the Chinese Academy of Sciences(CAS,Nos.2022055 and 2023065)+2 种基金support from the National Key Research and Development Program of China,grant 2022YFF0503404Funding for the DPAC has been provided by national institutions,in particular the institutions participating in the Gaia Multilateral AgreementFunding for the project has been provided by the National Development and Reform Commission。
文摘δScuti(δSct)stars are potential distance tracers for studying the Milky Way structure.We conduct a comprehensive analysis of the period-luminosity(PL)and period-luminosity-metallicity(PLZ)relations forδSct stars,integrating data from the Zwicky Transient Facility,the Transiting Exoplanet Survey Satellite,Large Sky Area Multi-Object Fiber Spectroscopic Telescope,Apache Point Observatory Galactic Evolution Experiment,and Gaia.To mitigate the impact of the Gaia parallax zero point offset,we applied a correction method,determining the optimal zero point value to be zp(?)=35±2μas.Using the three best bands,by varying the parallax error threshold,we found that the total error of the PLR zero point was minimized to 0.9%at a parallax error threshold of 6%.With this threshold,we derived the PL and PLZ relations for nine bands(from optical to mid-infrared)and five Wesenheit bands.Through our analysis,we conclude that the influence of metallicity on the PLR ofδSct stars is not significant,and the differences across various bands are minimal.
基金founded by the Gordon and Betty Moore Foundation through grants GBMF5490 and GBMF10501 to Ohio State Universitythe Alfred P.Sloan Foundation grant G-2021-14192
文摘We presented the first photometric light curve solutions of four W Ursae Majoris-type contact binary systems.This investigation utilized photometric data from the Transiting Exoplanet Survey Satellite and Gaia Data Release 3(DR3).We used the PHysics Of Eclipsing BinariEs Python code and the Markov Chain Monte Carlo method for these light curve solutions.Only TIC 249064185 among the target systems needed a cold starspot to be included in the analysis.Based on the estimated mass ratios for these total eclipse systems,three of them are categorized as low mass ratio contact binary stars.The absolute parameters of the systems were estimated using the Gaia DR3 parallax method and the orbital period and semimajor axis(P-a)empirical relationship.We ascertained that the TIC 318015356 and TIC 55522736 systems are A-subtypes,while TIC 249064185 and TIC 397984843 are W-subtypes,depending on each component’s effective temperature and mass.We estimated the initial masses of the stars,the mass lost by the binary system,and the systems’ages.We displayed star positions in the mass-radius,mass-luminosity,and total mass-orbital angular momentum diagrams.In addition,our findings indicate a good agreement with the mass-temperature empirical parameter relationship for the primary stars.
基金supported by the National Natural Science Foundation of China(NSFC,Nos.12203011 and 12033005)the support by Yunnan province Xingdian talent support program,Yunnan provincial Department of Science and Technology through grant No.202101BA070001-261+8 种基金Yunnan University Laboratory Open ProjectPhD research startup foundation of Chuxiong Normal Universitythe Xinjiang Uygur Autonomous Region of China for their support through the Tianchi Programsupported by the international partnership program of Chinese Academy of Sciences through grant No.114231KYSB20200009Shanghai Pujiang Program 20PJ1415500the science research grant from the China Manned Space Project with No.CMS-CSST-2021-B06support from NSFC through grant No.12303028support from the Natural Science Foundation of Xinjiang Uygur Autonomous Region(No.2024D01E37)the NSFC(12473025).
文摘Sulfur-bearing molecules are frequently detected in star-forming regions.The abundance ratio of SO to SO_(2)(hereafter,SO/SO_(2) ratio)has been proposed as a potential evolutionary tracer of star formation because tentative correlations have been found between SO/SO_(2) ratio and evolutionary stages.Nonetheless,the lack of highresolution observations and extensive statistical analyses of large samples raises questions regarding its efficacy as an evolutionary tracer.In this study,we analyze 31 protostellar cores with both SO and SO_(2) detection to investigate the relationship between the SO/SO_(2) ratio and two evolutionary parameters of chemical richness factor and gas temperatures.The correlations between SO/SO_(2) ratio and evolutionary parameters have been found,but these correlations are mainly contributed by low-mass cores rather than high-mass cores.Our findings suggest that the SO/SO_(2) ratio serves as a reliable evolutionary tracer for low-mass dense cores.In high-mass cores,the relationship between the SO/SO_(2) ratio and evolutionary stage remains ambiguous.This likely arises from both vigorous stellar feedback effects and the potential absence of distinct evolutionary stages analogous to those in low-mass cores.Consequently,higher-resolution observations with expanded statistical samples are required to assess the viability of SO/SO_(2) ratio as an evolutionary tracer for high-mass cores.
基金supported by the National Natural Science Foundation of China12203016,12173034,12322304 and 12173013Natural Science Foundation of Hebei Province No.A2022205018,A2021205006,226Z7604G+4 种基金Yunnan University grant No.C619300A034Science Foundation of Hebei Normal University No.L2022B33.W.Y.Cacknowledges the science research grants from the China Manned Space Projectthe support of Physics Postdoctoral Research Station at Hebei Normal Universitythe science research grants from the China Manned Space Project with NOs.CMS-CSST-2021-A09,CMS-CSST-2021-A08 and CMS-CSST-2021-B03。
文摘The availability of large data sets containing stellar parameters,distances,and extinctions for stars in the Milky Way,particularly within the Galactic disk,is essential for advancing our understanding of the Galaxy’s stellar populations,structure,kinematics,and chemical evolution.In this study,we present a catalog of stellar parameters,including effective temperature (T_(eff)),metallicity ([Fe/H]),absolute magnitudes (M_(G)),distances (d),and reddening values (E(G_(BP)-G_(RP))),for a sample of 141 million stars from the SkyMapper Southern Survey.These parameters are derived using the SPar algorithm,which employs a fitting procedure to match multi-band photometric observations and estimate the stellar properties (T_(eff),[Fe/H],M_(G),d,and E(G_(BP)-G_(RP))) on an individual star basis,following the methodology outlined in our previous work.This study successfully determines stellar parameters and extinction values simultaneously for stars located in high and low Galactic latitudes.The resulting stellar parameters and extinction values are in good agreement with results from other studies,demonstrating the robustness of our method.We derive a temperature dispersion of 195 K and a metallicity dispersion of 0.31 dex when comparing our results with spectroscopic data.The catalog produced in this work provides a valuable resource for future research on the Galactic metallicity distribution function,the structure of the Galaxy,threedimensional extinction mapping,and other related astrophysical topics.
