Astrophysics and Space Science最新文献

Slowly rotating white dwarfs in (f(R,mathcal{L}_{m},T)=R+alpha ,mathcal{L}_{m} T) gravity: moment of inertia, rotational mass shift and quadrupole moment 在(f(R,mathcal{L}_{m},T)=R+alpha ,mathcal{L}_{m} T)重力下缓慢旋转的白矮星：转动惯量，旋转质量位移和四极矩

IF 2.1 4区物理与天体物理

Astrophysics and Space Science Pub Date : 2026-11-06 DOI: 10.1007/s10509-026-04665-2

Kazi Abu Rousan

{"title":"Slowly rotating white dwarfs in (f(R,mathcal{L}_{m},T)=R+alpha ,mathcal{L}_{m} T) gravity: moment of inertia, rotational mass shift and quadrupole moment","authors":"Kazi Abu Rousan","doi":"10.1007/s10509-026-04665-2","DOIUrl":"10.1007/s10509-026-04665-2","url":null,"abstract":"<div><p><b>Purpose:</b> It is still open whether white dwarfs can exceed the Chandrasekhar limit and modified gravity is one way to get heavier stars. In <span>(f(R,mathcal{L}_{m},T)=R+alpha mathcal{L}_{m} T)</span>, with <span>(mathcal{L}_{m})</span> the matter Lagrangian and <span>(alpha )</span> the matter-geometry coupling, the static limiting mass is already above it. Here we include rotation. <b>Methods:</b> We take the Hartle-Thorne expansion to second order in the angular velocity and derive every closure from the modified conservation law. Because <span>(f_{R}=1)</span>, the system becomes general relativity with a conserved barotropic effective fluid as source. This also makes the general-relativistic limit easy to see and decides which particle number enters the first law. <b>Results:</b> Across the couplings studied the static limiting mass runs from 1.34 to <span>(1.50 M_{odot })</span>. For <span>(alpha >0)</span> the sequence ends before any turning point, where the sound speed of the effective fluid reaches the speed of light. Rotation multiplies each limit by 1.064 to 1.078, almost independently of <span>(alpha )</span>, reaching <span>(1.61 M_{odot })</span>. The two rotational mass shifts differ by three orders of magnitude, <span>(3.3times 10^{-5})</span> at fixed particle number and <span>(8.1%)</span> at fixed central density. The quadrupole from the relativistic exterior match agrees with a Radau volume integral to <span>(0.3%)</span>. <b>Conclusion:</b> These are the first rotating white-dwarf models in this theory. They reach second order in the rotation and at <span>(alpha =0)</span> reproduce published general-relativistic ones. Coupling and rotation raise the limiting mass by similar amounts, so a static bound on <span>(alpha )</span> assumes slow rotation. The two effects can be separated through the moment of inertia, which responds to the coupling about 2.5 times more strongly than the radius at fixed mass.</p></div>","PeriodicalId":8644,"journal":{"name":"Astrophysics and Space Science","volume":"371 11","pages":""},"PeriodicalIF":2.1,"publicationDate":"2026-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149339003","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Effects of initial binary fraction on dynamical evolution of open clusters 初始二元分数对开放团簇动态演化的影响

IF 2.1 4区物理与天体物理

Astrophysics and Space Science Pub Date : 2026-11-06 DOI: 10.1007/s10509-026-04662-5

Xinhao Yi, Zhongmu Li, Mengtao Li, Xiaoya Zheng, Chaolin Yu, Bingjie Qian, Jie Lan

{"title":"Effects of initial binary fraction on dynamical evolution of open clusters","authors":"Xinhao Yi, Zhongmu Li, Mengtao Li, Xiaoya Zheng, Chaolin Yu, Bingjie Qian, Jie Lan","doi":"10.1007/s10509-026-04662-5","DOIUrl":"10.1007/s10509-026-04662-5","url":null,"abstract":"<div><p>Binary systems are a key factor influencing the dynamical evolution of open clusters. Previous studies have shown that binary populations are closely related to the dynamical evolutionary stages of young open clusters. We employ the direct N-body code NbodyCP to investigate the dynamical evolution of open clusters with initial binary fractions of 10%, 30%, and 50%. For each model, ten independent random realisations were performed using different random seeds to quantify the stochastic variations associated with the initial conditions, while the global model parameters were kept unchanged. The results show that the initial binary fraction exerts a clear influence on the dynamical and stellar evolutionary properties of open clusters. Models with higher initial binary fractions exhibit broader relative velocity-component distributions, with systematically larger velocity dispersions. The tidal radius decreases in all three models over the course of the 200 Myr evolution, with the 50% binary-fraction model showing the largest relative reduction. The Hertzsprung–Russell diagrams further show modest differences in the evolved stellar populations among the three models at later evolutionary stages, while the normalised stellar-population fractions remain broadly comparable. In addition, the core-radius evolution shows that the 30% and 50% models produce more compact and exhibit smaller large-scale fluctuations than the 10% model during the later evolutionary stage. These results suggest that primordial binaries play an important role in stellar population evolution and the internal structural evolution of open clusters.</p></div>","PeriodicalId":8644,"journal":{"name":"Astrophysics and Space Science","volume":"371 11","pages":""},"PeriodicalIF":2.1,"publicationDate":"2026-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149339002","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Quasiparticle modeling of strange quark stars with in-medium QCD effects at finite temperature and strong magnetic fields 在有限温度和强磁场条件下具有介质QCD效应的奇异夸克星的准粒子模型

IF 2.1 4区物理与天体物理

Astrophysics and Space Science Pub Date : 2026-11-03 DOI: 10.1007/s10509-026-04663-4

Yogesh Kumar, Mihir Arora, Manas Lohani, Poonam Jain, Pargin Bangotra, Rajeev

{"title":"Quasiparticle modeling of strange quark stars with in-medium QCD effects at finite temperature and strong magnetic fields","authors":"Yogesh Kumar, Mihir Arora, Manas Lohani, Poonam Jain, Pargin Bangotra,  Rajeev","doi":"10.1007/s10509-026-04663-4","DOIUrl":"10.1007/s10509-026-04663-4","url":null,"abstract":"<div><p>This work investigates the properties of spin-polarized strange quark matter (SQM) and the resulting structure of strange quark stars (SQSs) within a thermodynamically self-consistent quasiparticle framework. We construct a dynamic bag constant that is intrinsically coupled to the medium-dependent reduction of quark effective masses, thereby maintaining thermodynamic consistency as the density, temperature, and magnetic field vary. The model incorporates finite-temperature effects, strong magnetic fields, local electric charge neutrality, and weak beta equilibrium. The resulting equation of state (EoS) exhibits a temperature-dependent stiffening and a non-monotonic evolution of the squared speed of sound before approaching the conformal limit at high energy density. Solving the Tolman–Oppenheimer–Volkoff equations, we obtain maximum gravitational masses of <span>(1.66~M_{odot })</span>, <span>(1.87~M_{odot })</span>, and <span>(2.19~M_{odot })</span> at <span>(T=0)</span>, 30, and <span>(50text{ MeV})</span>, respectively, for a baseline magnetic field of <span>(10^{15})</span> G. We further examine the effect of stronger magnetic fields and compare the resulting stellar configurations with an Einstein–Maxwell–Dilaton equation of state. The results demonstrate the ability of the magnetized, finite-temperature quasiparticle framework to produce stable strange-star configurations with masses above <span>(2~M_{odot })</span>.</p></div>","PeriodicalId":8644,"journal":{"name":"Astrophysics and Space Science","volume":"371 11","pages":""},"PeriodicalIF":2.1,"publicationDate":"2026-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149309760","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Comparison of models for dynamical structures of solar plasma 太阳等离子体动力学结构模型的比较

IF 2.1 4区物理与天体物理

Astrophysics and Space Science Pub Date : 2026-10-28 DOI: 10.1007/s10509-026-04660-7

Sergey N. Artekha

{"title":"Comparison of models for dynamical structures of solar plasma","authors":"Sergey N. Artekha","doi":"10.1007/s10509-026-04660-7","DOIUrl":"10.1007/s10509-026-04660-7","url":null,"abstract":"<div><p>Possible mechanisms of generation of dynamical plasma structures are associated with the Schwarzschild criterion for convective instability and with excess energy (heat, magnetic): due to the superadiabatic temperature gradient, the overheated plasma starts to rise. In the framework of Navier-Stokes MHD equations, the complete system of equations for the full axisymmetric plasma model includes equations for the stream function, the azimuthal velocity component, the density change, the flow function of poloidal magnetic field, and the azimuthal component of the magnetic field. Within the framework of ideal hydrodynamics, the simplest plasma model is applicable to the initial stage of generation of plasma structures. In this case, rigorous analytical solutions are constructed from blocks. Within the framework of ideal hydrodynamics, some intermediate model – the refined model considers rotating plasma at the growth stage. In this case, some unidirectional differential rotation occurs. The full model studies the development of structures as rotating plasma from the very beginning to the highest development stage. The velocity field is adjusted to boundary conditions. Velocity components change in a coordinated manner. The stationary axisymmetric ambient magnetic field and its gradients have little effect on the plasma structure and velocity field. The movement structures for all models are similar. Radial flows converge towards the axis at the bottom, and there is an outflow to the periphery near the top of the plasma structure. The maximum vertical velocity component is reached at the center of the axis. Applications of these models to solar structures, including jets, are discussed.</p></div>","PeriodicalId":8644,"journal":{"name":"Astrophysics and Space Science","volume":"371 10","pages":""},"PeriodicalIF":2.1,"publicationDate":"2026-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149339365","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Nonlinear dust-ion-acoustic waves in a collisional dusty plasma with streaming dust: exact wave solutions and multisoliton structures 流尘碰撞等离子体中的非线性尘-离子-声波：精确波解和多孤子结构

IF 2.1 4区物理与天体物理

Astrophysics and Space Science Pub Date : 2026-10-28 DOI: 10.1007/s10509-026-04647-4

Ibrahim Elshamy, R. E. Tolba, M. E. Shaheen, M. A. M. Eltaweel

{"title":"Nonlinear dust-ion-acoustic waves in a collisional dusty plasma with streaming dust: exact wave solutions and multisoliton structures","authors":"Ibrahim Elshamy, R. E. Tolba, M. E. Shaheen, M. A. M. Eltaweel","doi":"10.1007/s10509-026-04647-4","DOIUrl":"10.1007/s10509-026-04647-4","url":null,"abstract":"<div><p>Nonlinear dust-ion-acoustic waves are investigated in a collisional dusty plasma consisting of negatively charged streaming dust grains, inertial positive ions, Maxwellian electrons, and a neutral background. The model incorporates ion-neutral and dust-neutral collisions, ionization, recombination, ion-drag force, and ion viscosity. Using the reductive perturbation technique, the governing fluid equations are reduced to an extended Korteweg-de Vries-Burgers (KdV-Burgers) equation describing the nonlinear evolution of dust-ion-acoustic perturbations. The resulting equation is analyzed using the truncated Painlevé expansion method and Hirota’s bilinear method to derive exact nonlinear wave solutions. The analysis yields various nonlinear structures, including cnoidal, solitary, asymmetric periodic, and two-soliton waves. The properties of these structures are strongly governed by the dust-to-ion temperature ratio, dust charge-density ratio, dust charge number, and initial streaming velocity of the negatively charged dust grains. In particular, increasing the dust streaming velocity suppresses the wave amplitude, whereas increasing the dust charge-density ratio and dust charge number enhances the amplitude of solitary structures. These results demonstrate that dust streaming, dust-charge effects, thermal effects, and collisional dissipation play important roles in determining the nonlinear evolution and morphology of dust-ion-acoustic waves. The present findings provide useful insights into nonlinear electrostatic wave dynamics in collisional dusty-plasma environments relevant to ionospheric and space plasmas.</p></div>","PeriodicalId":8644,"journal":{"name":"Astrophysics and Space Science","volume":"371 10","pages":""},"PeriodicalIF":2.1,"publicationDate":"2026-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149339366","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Quantifying the lunar impact on astronomical observations using a machine learning framework for visibility prediction 使用能见度预测的机器学习框架量化月球对天文观测的影响

IF 2.1 4区物理与天体物理

Astrophysics and Space Science Pub Date : 2026-10-27 DOI: 10.1007/s10509-026-04657-2

Hao Fu, Hou-Yuan Lin, Chen Zhang, Jian-Ning Xiong

{"title":"Quantifying the lunar impact on astronomical observations using a machine learning framework for visibility prediction","authors":"Hao Fu, Hou-Yuan Lin, Chen Zhang, Jian-Ning Xiong","doi":"10.1007/s10509-026-04657-2","DOIUrl":"10.1007/s10509-026-04657-2","url":null,"abstract":"<div><p>Moonlight interference is a primary limiting factor for the spatiotemporal coverage of ground-based observation systems. To address this, we quantify the lunar impact on target visibility and provide visibility probability predictions across varying lunar phases, lunar separations, brightness and aerosol optical depth. The optimization of lunar impact is primarily applicable to high-altitude and geostationary orbit (GEO) targets, for which lunar interference avoidance and observation scheduling are of practical importance. We collected 15 months of data via a moon-centered cross distribution sampling strategy that prioritizes nearby targets over distant ones. Using density-based spatial clustering of applications with noise (DBSCAN), we derived the contours for concentrated samples in the parameter space, enabling the determination of limiting visibility conditions for each lunar period, the quantification of the waste rate of static avoidance strategies, and simple visibility discrimination based on fixed thresholds. Based on the fully connected residual network-18 (FC ResNet-18), we further predicted visibility probabilities for targets under varying lunar phases, lunar separations, brightness and aerosol optical depth. By comparing the conditional probability distributions derived from DBSCAN and FC ResNet-18, we deem that the latter is compatible with the discriminant logic of the former. When applied to high-altitude and GEO satellite visibility prediction, the model achieves a mean positive-class entropy of 0.100–0.229 during weak moonlight and moonless periods, and 0.115–0.125 during strong moonlight periods. The results demonstrate the effectiveness of the visibility prediction model under lunar impact.</p></div>","PeriodicalId":8644,"journal":{"name":"Astrophysics and Space Science","volume":"371 10","pages":""},"PeriodicalIF":2.1,"publicationDate":"2026-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149339183","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

RFI classification and weakly supervised time–frequency flagging with confidence-screened pseudo-label expansion for a small radio telescope array 小型射电望远镜阵列的RFI分类和弱监督时频标记与置信度筛选伪标签展开

IF 2.1 4区物理与天体物理

Astrophysics and Space Science Pub Date : 2026-10-26 DOI: 10.1007/s10509-026-04656-3

Guiyuan Wang, Rushuang Zhao, Wenjun Xiao, Ziyi You, Baoqiang Lao, Hui Liu, You Lu, Xing Huang, Haowen Mu, Luqun Zhu, Zefeng Tu, Q. J. Zhi, Q. Zhou, Yi Zhou, D. Y. Yan

{"title":"RFI classification and weakly supervised time–frequency flagging with confidence-screened pseudo-label expansion for a small radio telescope array","authors":"Guiyuan Wang, Rushuang Zhao, Wenjun Xiao, Ziyi You, Baoqiang Lao, Hui Liu, You Lu, Xing Huang, Haowen Mu, Luqun Zhu, Zefeng Tu, Q. J. Zhi, Q. Zhou, Yi Zhou, D. Y. Yan","doi":"10.1007/s10509-026-04656-3","DOIUrl":"10.1007/s10509-026-04656-3","url":null,"abstract":"<div><p>Radio frequency interference (RFI) analysis for small radio telescope arrays requires both morphology classification and time–frequency localization, despite scarce site-specific labels, long-tailed class distributions, and strict latency constraints. Using baseband data from the 4 m × 4.5 m array at Guizhou Normal University, we develop a confidence-screened pseudo-label expansion procedure for seven-class classification and weakly supervised flagging. Trained with Group Normalization and weighted sampling, the SmallCNN_GN_V2 classifier achieves 95.37% accuracy, 94.82% macro-F1, and 92.00% rare-class recall on a held-out 432-sample gold-standard test set. Its mean single-tile CNN latency is 0.43 ms on an NVIDIA A40 GPU, excluding preprocessing and data transfer. We further augment the reviewed classification samples with rule-assisted binary and class-valued masks. Because these masks are spot-checked by humans rather than densely annotated at the pixel level, the segmentation metrics quantify agreement with the weak targets. At a calibrated threshold, a lightweight joint segmentation–classification model achieves 74.31% Dice/F1 and 59.13% IoU, while retaining 90.68% image-level accuracy. Under the same tile protocol, an AOFlagger-like statistical baseline achieves 53.33% Dice/F1 and 36.36% IoU. An exploratory field case study illustrates morphology-assisted inspection of approximate <span>mtime</span>-binned activity and candidate source families. This low-latency CNN front end is relevant to pulsar-search quality control, in which impulsive and periodic RFI can create false candidates, although no pulsar-recovery test is included here. The framework extends low-latency RFI classification to weakly supervised localization for small-array monitoring.</p></div>","PeriodicalId":8644,"journal":{"name":"Astrophysics and Space Science","volume":"371 10","pages":""},"PeriodicalIF":2.1,"publicationDate":"2026-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149338842","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Effect of lunar free oscillations on TianQin’s range acceleration noise 月球自由振荡对天琴距离加速度噪声的影响

IF 2.1 4区物理与天体物理

Astrophysics and Space Science Pub Date : 2026-10-22 DOI: 10.1007/s10509-026-04659-0

Zongcan Liu, Ye Xu, Kun Liu, Xuefeng Zhang

引用次数: 0

White-light flare in AR 13842: a multi-observable analysis of the 2024 October 3 X9.0 event ar13842中的白光耀斑：对2024年10月3日X9.0事件的多观测分析

IF 2.1 4区物理与天体物理

Astrophysics and Space Science Pub Date : 2026-10-21 DOI: 10.1007/s10509-026-04649-2

Luthfi Naufal, Dhani Herdiwijaya, Dwi Irwanto

{"title":"White-light flare in AR 13842: a multi-observable analysis of the 2024 October 3 X9.0 event","authors":"Luthfi Naufal, Dhani Herdiwijaya, Dwi Irwanto","doi":"10.1007/s10509-026-04649-2","DOIUrl":"10.1007/s10509-026-04649-2","url":null,"abstract":"<div><p>We present a multi-observable analysis of the white-light flare (WLF) in NOAA Active Region 13842 during the X9.0-class solar flare of 2024 October 3, the largest flare of Solar Cycle 25 to date. Using Solar Dynamics Observatory (SDO) observations from the Helioseismic and Magnetic Imager (HMI), we utilize three complementary data products derived from the Fe <span>i</span> 6173 Å spectral line (corrected continuum intensity, line-of-sight magnetogram, and line-of-sight Dopplergram) as observables of the WLF and its associated photospheric spectral signatures. We develop a per-pixel transient detection metric that distinguishes flare-induced brightening from secular morphological changes, and apply it to the tracked image stacks. The corrected continuum exhibits a coherent brightening with a mean contrast of 2.5% within the WLF region of interest and a peak pixel-wise contrast of 49.9%, distributed across two ribbon-like kernels covering a total area of 164 Mm<sup>2</sup>. The magnetogram and Dopplergram simultaneously exhibit transient excursions of <span>(Delta |B| approx 17)</span> G and <span>(Delta |V| approx 136)</span> m s<sup>−1</sup> at the same location, which we interpret as artifacts of flare-induced distortion of the Fe <span>i</span> 6173 Å spectral line rather than physical changes in the photospheric plasma. The three transient footprints overlap with Dice coefficients of 0.34–0.44 against a random expectation of 0.10, with centroid separations of 1.4–1.6 Mm, a few per cent of the footprint extent, and their temporal ordering is resolved at the 45 s cadence. Together with the temporal synchronization of the three signatures, this provides a strong multi-observable confirmation of the WLF.</p></div>","PeriodicalId":8644,"journal":{"name":"Astrophysics and Space Science","volume":"371 10","pages":""},"PeriodicalIF":2.1,"publicationDate":"2026-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149234758","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A novel approach to identify unseen companions: an in-depth study of GDR3 220_28 一种识别看不见的伴星的新方法：对gdr3220_28的深入研究

IF 2.1 4区物理与天体物理

Astrophysics and Space Science Pub Date : 2026-10-21 DOI: 10.1007/s10509-026-04652-7

T. B. Cysil, Blesson Mathew, B. Shridharan, S. Muneer, Pramod Kumar S, S. Nidhi, Sreeja S Kartha, Suman Bhattacharyya, T. Robin

{"title":"A novel approach to identify unseen companions: an in-depth study of GDR3 220_28","authors":"T. B. Cysil, Blesson Mathew, B. Shridharan, S. Muneer, Pramod Kumar S, S. Nidhi, Sreeja S Kartha, Suman Bhattacharyya, T. Robin","doi":"10.1007/s10509-026-04652-7","DOIUrl":"10.1007/s10509-026-04652-7","url":null,"abstract":"<div><p>Emission lines in the spectrum and the excess seen in the spectral energy distribution (SED) at infrared (IR) wavelengths serve as crucial indicators of accretion activity and the presence of gas and dust in the circumstellar environment of a young star. As accretion ceases over several million years, the H<span>(alpha )</span> emission diminishes. However, IR excess combined with negligible H<span>(alpha )</span> emission could also extend to indicate certain close binary systems, where a circumbinary disk contributes to the observed excess. Additionally, in unresolved binaries, companion stars can contribute to the photometry, leading to inaccuracies in parameter measurements and skewed positions in the color-magnitude diagram (CMD). We identify a photometrically peculiar object from a survey of the Cepheus star-forming regions (SFRs), Gaia DR3 2205212960562531328, exhibiting a shift from its expected position in the CMD, as indicated by the Gaia optical photometry. This peculiarity drives our research, prompting an investigation through an approach that combines astrometric accuracy, photometric modeling and spectroscopic studies. The Gaia XP spectrum of the source shows a systematic blue excess, indicating an additional hotter unresolved component. Two-component SED modelling yields a companion with <span>(T_{mathrm{eff}}sim 27{,}000text{ K})</span> and <span>(log gge 4.5)</span>, consistent with sdB stars. Further CMD and spectroscopic analyses support a binary system consisting of an A0-type PMS star with an sdB companion. In addition, ZTF photometry shows tentative evidence for a periodicity of 0.498 days. This study paves the way for a systematic search of similar binary systems that would otherwise remain unidentified.</p></div>","PeriodicalId":8644,"journal":{"name":"Astrophysics and Space Science","volume":"371 10","pages":""},"PeriodicalIF":2.1,"publicationDate":"2026-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149234757","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0