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Measuring Track-Related Pointing Errors on the Nanshan Radio Telescope with an Optical Pointing Telescope Adv. Astron. (IF 1.4) Pub Date : 2024-3-14 Ye Yuan, Zhi-Yong Liu, Na Wang
The need for precise radio telescope pointing has driven great attention to investigating the effect of antenna local deformation or irregularity, such as unevenness in the azimuth track. Although the track-alidade interaction model is commonly used to investigate the pointing effect of track unevenness (such as the works on DSN 34 m antennas and the Green Bank Telescope), few experiments have been
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Tracking and Disturbance Suppression of the Radio Telescope Servo System Based on the Equivalent-Input-Disturbance Approach Adv. Astron. (IF 1.4) Pub Date : 2024-3-8 Lei Yang, Na Wang, Zhiyong Liu, Ning Li
This paper presents a composite control algorithm for the radio telescope servo control system to address the target tracking and matched/mismatched disturbance suppression problems. The algorithm consists of the equivalent-input-disturbance (EID) approach and the optimal control method. An EID estimator is developed using the difference between the estimated output of the state observer and the measurement
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Dark Energy from Cosmological Energy Conservation Adv. Astron. (IF 1.4) Pub Date : 2023-10-27 Manuel Uruena Palomo
The value of the gravitational wave energy density is unknown. Current progress in gravitational wave detection suggests that the energy density of the stochastic gravitational wave background (SGWB) will be estimated in the next decades. A derivation of its value is presented under the assumption that energy lost due to cosmic redshift is fully responsible for the energy gained by the cosmological
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The Predictions of Noncollinear Equilibria Positions in ER3BP with Yukawa-Like Corrections Adv. Astron. (IF 1.4) Pub Date : 2023-7-25 E. Baby Anitha, Tenaw Tilahun Asmamaw, M. Javed Idrisi
The existence and stability of noncollinear equilibrium points in the elliptic restricted three-body problem under the consideration of Yukawa correction to Newtonian potential are studied in this paper. The effects of various parameters (μ, ê, α, and λ) on the noncollinear equilibrium points are discussed briefly, and it is found that only ordinate of noncollinear equilibria E4,5 is affected by Yukawa
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A New Approach to Astronomical Data Analysis Based on Multiple Variables Adv. Astron. (IF 1.4) Pub Date : 2023-7-6 Prasenjit Banerjee, Asis Kumar Chattopadhyay, Soumita Modak
Data analysis for a sample of celestial bodies generally is preceded by the completeness test in order to verify whether the sample objects are proper representatives of the corresponding part of the universe. A data set following a multivariate, continuous, uniform distribution is said to be “complete in space.” This paper introduces a new approach to check for this completeness for any astronomical
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Propagation of Nonlinear Dust-Acoustic Waves in a Self-Gravitating Collision Magnetized Dusty Plasma in Earth’s Magnetosphere Adv. Astron. (IF 1.4) Pub Date : 2023-6-29 Aljawhara H. Almuqrin, Mohammed F. Alotiby, R. E. Tolba
The nonlinear propagation of different types of DANW acoustic dust nonlinear waves has been investigated in a magnetized dusty plasma consisting of negatively charged dust particles, Maxwellian electrons, and ions. Application of the standard reductive perturbation theory is used to derive the corresponding three-dimensional nonlinear a complex Ginzburg–Landau (3D-CGLE) equation which governs the dynamics
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Noncollinear Equilibrium Points in CRTBP with Yukawa-Like Corrections to Newtonian Potential under an Oblate Primary Model Adv. Astron. (IF 1.4) Pub Date : 2023-6-15 M. Javed Idrisi, Sunusi Haruna, Teklehaimanot Eshetie
This study is about the effects of Yukawa-like corrections to Newtonian potential on the existence and stability of noncollinear equilibrium points in a circular restricted three-body problem when bigger primary is an oblate spheroid. It is observed that ∂x0/∂λ = 0 = ∂y0/∂λ at λ0 = 1/2, so we have a critical point λ0 = 1/2 at which the maximum and minimum values of x0 and y0 can be obtained, where
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Thermal Modeling of Oxia Planum: Thermophysical Characterization of the Dark Resistant Unit (DRU) in the Germania Lacus Adv. Astron. (IF 1.4) Pub Date : 2023-6-9 M. Formisano, F. Altieri, A. Frigeri, M. C. De Sanctis, C. Federico, G. Magni, E. Ammannito, S. De Angelis, M. Ferrari
The aim of this work is to characterize, from a thermophysical perspective, the dark resistant unit (DRU) characterizing Germania Lacus in the Oxia Planum Region, providing new insights to constrain the nature of the materials which compose this unit. We investigated the temperature distribution of the DRU by adopting common values of the thermophysical parameters of the basalt and by exploring several
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Research on Wind Flow Control by Windbreak Fence for a Large Radio Telescope Site Based on Numerical Simulations Adv. Astron. (IF 1.4) Pub Date : 2023-5-17 Feilong He, Qian Xu, Na Wang
The higher the pointing accuracy of the radio telescope, the more obvious the influence of wind disturbance on antenna performance. Taking the site of the 110 m aperture QiTai radio Telescope (QTT) as an example, the terrain and air flow characteristics of the site are studied. It is found that the wind direction with high incoming wind frequency and relatively high speed is mostly located in the mountain
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Restricted Concave Kite Five-Body Problem Adv. Astron. (IF 1.4) Pub Date : 2023-4-19 A. R. Kashif, M. Shoaib
The restricted concave kite five-body problem is a problem in which four positive masses, called the primaries, rotate in the concave kite configuration with a mass at the center of the triangle formed by three of the primaries. The fifth body has negligible mass and does not influence the motion of the four primaries. It is assumed that the fifth mass is in the same plane of the primaries and that
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Measuring Antenna Elevation Mechanism Pointing Errors with Multiencoder Information Sources Adv. Astron. (IF 1.4) Pub Date : 2023-4-13 Duoxiang Xu, Qian Xu, Na Wang, Fei Xue
There are many factors that cause pointing errors in radio telescopes. As one of the motion positioning mechanisms of the radio telescope, the error caused by the elevation mechanism cannot be ignored. The source of error in the elevation mechanism comes mainly from the key transmission components and the support structure. Accurate measurement of the errors caused by them is the key to analyzing their
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Numerical Simulation and Test Study on Track Welding of QTT Adv. Astron. (IF 1.4) Pub Date : 2023-3-23 Duoxiang Xu, Qian Xu, Lin Li, Hui Wang, Na Wang
Considering the stringent requirement of the pointing accuracy up to 2.5″ of the world’s largest full steerable radio telescope, this paper studies the welding experiment of the azimuth track of the antenna. First, the opposite deformation jig and welding process were designed for the QTT’s azimuth track. Then, the welding process was numerically simulated using a finite element model. The simulation
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Reanalysis of the Spin Direction Distribution of Galaxy Zoo SDSS Spiral Galaxies Adv. Astron. (IF 1.4) Pub Date : 2023-2-21 Darius Mcadam, Lior Shamir
The distribution of the spin directions of spiral galaxies in the Sloan Digital Sky Survey has been a topic of debate in the past two decades, with conflicting conclusions reported even in cases where the same data were used. Here, we follow one of the previous experiments by applying the SpArcFiRe algorithm to annotate the spin directions in an original dataset of Galaxy Zoo 1. The annotation of the
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Some Bianchi Type Viscous Holographic Dark Energy Cosmological Models in the Brans–Dicke Theory Adv. Astron. (IF 1.4) Pub Date : 2022-11-2 M. Vijaya Santhi, T. Chinnappalanaidu, S. Srivani Madhu, Daba Meshesha Gusu
In this article, we analyze Bianchi type–II, VIII, and IX spatially homogeneous and anisotropic space-times in the background of the Brans–Dicke theory of gravity within the framework of viscous holographic dark energy. To solve the field equations, we have used the relation between the metric potentials as and the relation between the scalar field and the scale factor as . Also, we have discussed
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The Restricted Six-Body Problem with Stable Equilibrium Points and a Rhomboidal Configuration Adv. Astron. (IF 1.4) Pub Date : 2022-08-17 M. A. R. Siddique, A. R. Kashif
We explore the central configuration of the rhomboidal restricted six-body problem in Newtonian gravity, which has four primaries (where ) at the vertices of the rhombus , , , and , respectively, and a fifth mass is at the point of intersection of the diagonals of the rhombus, which is placed at the center of the coordinate system (i.e., at the origin ). The primaries at the rhombus’s opposite vertices
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Artificial Controlling of the Collinear Liberation Points Using Lorentz Force in the Restricted Three-Body Problem Adv. Astron. (IF 1.4) Pub Date : 2022-07-23 M.I. El-Saftawy, M.A. Yousef, A. Mostafa
This work studies the possibility of generating artificial collinear liberation points for the planar circular restricted three-body problem using Lorentz force affecting a charged spacecraft due to the magnetic field of a planet. It is considered to be a magnetic dipole inclined by angle α with the spin axis of the planet. The acceleration components for Lorentz force are first derived in an inertial
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A High-Precision Dynamic Six Degree-of-Freedom Pose Measurement of the Subreflectors of Large Antennas Based on a Position Sensitive Detector and Laser Array Adv. Astron. (IF 1.4) Pub Date : 2022-07-05 Shangmin Lin, Wei Wang, Hu Wang, Yang Song, Yue Pan, Jiang Qiao, Yaoke Xue, Qinfang Chen, Meiying Liu, Yang Shen, Jie Liu, Yang Liu, Yongjie Xie, Canglong Zhou
Subreflector misalignment of a large steerable radio telescope induces a pointing error and reduces the gain of the antenna system. To improve the antenna’s operational efficiency, it is necessary to measure and adjust the position and attitude of the subreflector in real time. In this paper, a method based on a position sensitive detector (PSD) and laser array without an optical system is proposed
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Analysis of ∼106 Spiral Galaxies from Four Telescopes Shows Large-Scale Patterns of Asymmetry in Galaxy Spin Directions Adv. Astron. (IF 1.4) Pub Date : 2022-05-31 Lior Shamir
The ability to collect unprecedented amounts of astronomical data has enabled the nomical data has enabled the stu scientific questions that were impractical to study in the pre-information era. This study uses large datasets collected by four different robotic telescopes to profile the large-scale distribution of the spin directions of spiral galaxies. These datasets cover the Northern and Southern
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Existential Properties of Algebraic Integrals of a Rigid Body Adv. Astron. (IF 1.4) Pub Date : 2022-04-22 A. I. Ismail, W. S. Amer
In this article, we consider kinematical considerations of a rigid body rotating around a given fixed point in a Newtonian force field exerted by an attractive center with a rotating couple about their principal axes of inertia. The kinematic equations and their well-known three elementary integrals of the problem are introduced. The existence properties of the algebraic integrals are considered. Besides
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Testing Correspondence between Areas with Hydrated Minerals, as Observed by CRISM/MRO, and Spots of Enhanced Subsurface Water Content, as Found by DAN along the Traverse of Curiosity Adv. Astron. (IF 1.4) Pub Date : 2022-04-01 M. V. Djachkova, I. G. Mitrofanov, S. Y. Nikiforov, D. I. Lisov, M. L. Litvak, A. B. Sanin
Possible correlation is studied between Water Equivalent Hydrogen (WEH) in the Martian subsurface, as measured by the DAN (Dynamic Albedo of Neutrons) instrument along the Curiosity traverse, and the presence of hydrated minerals on the surface, as seen from the orbit by CRISM (Compact Reconnaissance Imaging Spectrometer for Mars) instrument onboard MRO (Mars Reconnaissance Orbiter). Cross-analysis
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Artificial Triangular Points by Lorentz Force in the Restricted Three-Body Problem Adv. Astron. (IF 1.4) Pub Date : 2022-03-22 A. Mostafa, M. A. Yousef, M. I. El-Saftawy
The restricted three body problem was outlined. The acceleration due to planetary magnetic field, in terms of space craft’s orbital elements, was analysed. The conditions for calculating the liberation points including the mutual gravitational attraction and the effect of Lorentz acceleration were derived for the case of circular planer restricted three bodies. The stability of the solution for the
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Automated Stellar Spectra Classification with Ensemble Convolutional Neural Network Adv. Astron. (IF 1.4) Pub Date : 2022-01-04 Zhuang Zhao, Jiyu Wei, Bin Jiang
Large sky survey telescopes have produced a tremendous amount of astronomical data, including spectra. Machine learning methods must be employed to automatically process the spectral data obtained by these telescopes. Classification of stellar spectra by applying deep learning is an important research direction for the automatic classification of high-dimensional celestial spectra. In this paper, a
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Brine-Induced Tribocorrosion Accelerates Wear on Stainless Steel: Implications for Mars Exploration Adv. Astron. (IF 1.4) Pub Date : 2021-12-28 Javier Martín‐Torres, María‐Paz Zorzano‐Mier, Erik Nyberg, Abhilash Vakkada-Ramachandran, Anshuman Bhardwaj
Tribocorrosion is a degradation phenomenon of material surfaces subjected to the combined action of mechanical loading and corrosion attack caused by the environment. Although corrosive chemical species such as materials like chloride atoms, chlorides, and perchlorates have been detected on the Martian surface, there is a lack of studies of its impact on materials for landed spacecraft and structures
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Modeling of the Dark Phase of Flight and the Impact Area for Meteorites of Real Shapes Adv. Astron. (IF 1.4) Pub Date : 2021-12-23 Karol Havrila, Juraj Tóth, Leonard Kornoš
Aims. The complex dynamics of bodies, originating from the interplanetary matter and passing through Earth’s atmosphere, defines their further position, velocity, and final location on Earth’s surface in the form of meteorites. One of the important factors that affect the movement of a body in the atmosphere is its shape and orientation. Our goal is to model the interaction of real shape meteoroids
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Predicting Pulsars from Imbalanced Dataset with Hybrid Resampling Approach Adv. Astron. (IF 1.4) Pub Date : 2021-12-03 Ernesto Lee, Furqan Rustam, Wajdi Aljedaani, Abid Ishaq, Vaibhav Rupapara, Imran Ashraf
Pulsar stars, usually neutron stars, are spherical and compact objects containing a large quantity of mass. Each pulsar star possesses a magnetic field and emits a slightly different pattern of electromagnetic radiation which is used to identify the potential candidates for a real pulsar star. Pulsar stars are considered an important cosmic phenomenon, and scientists use them to study nuclear physics
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Subsurface Thermal Modeling of Oxia Planum, Landing Site of ExoMars 2022 Adv. Astron. (IF 1.4) Pub Date : 2021-09-02 M. Formisano, M. C. De Sanctis, C. Federico, G. Magni, F. Altieri, E. Ammannito, S. De Angelis, M. Ferrari, A. Frigeri
Numerical simulations are required to thermophysically characterize Oxia Planum, the landing site of the mission ExoMars 2022. A drilling system is installed on the ExoMars rover, and it will be able to analyze down to 2 meters in the subsurface of Mars. The spectrometer Ma_MISS (Mars Multispectral Imager for Subsurface, Coradini and Da Pieve, 2001) will investigate the lateral wall of the borehole
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Periodic Variation of Solar Flare Index for the Last Solar Cycle (Cycle 24) Adv. Astron. (IF 1.4) Pub Date : 2021-08-24 Atila Ozguc, Ali Kilcik, Volkan Sarp, Hülya Yeşilyaprak, Rıza Pektaş
In this study, we used the flare index (FI) data taken from Kandilli Observatory for the period of 2009–2020. The data sets are analyzed in three categories as Northern Hemisphere, Southern Hemisphere, and total FI data sets. Total FI data set is obtained from the sum of Northern and Southern Hemispheric values. In this study, the periodic variations of abovementioned three categories FI data sets
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Spectral Energy Density in an Axisymmetric Galaxy as Predicted by an Analytical Model for the Maxwell Field Adv. Astron. (IF 1.4) Pub Date : 2021-08-02 Mayeul Arminjon
An analytical model for the Maxwell radiation field in an axisymmetric galaxy, proposed previously, is first checked for its predictions of the spatial variation of the spectral energy distributions (SEDs) in our Galaxy. First, the model is summarized. It is now shown how to compute the SED with this model. Then the model is adjusted by asking that the SED predicted at our local position in the Galaxy
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Fractal Basins of Convergence of a Seventh-Order Generalized Hénon–Heiles Potential Adv. Astron. (IF 1.4) Pub Date : 2021-07-14 Euaggelos E. Zotos, Fredy L. Dubeibe, A. Riaño-Doncel
This article aims to investigate the points of equilibrium and the associated convergence basins in a seventh-order generalized Hénon–Heiles potential. Using the well-known Newton–Raphson iterator, we numerically locate the positions of the points of equilibrium, while we also obtain their linear stability. Furthermore, we demonstrate how the two variable parameters, entering the generalized Hénon–Heiles
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Stability Analysis of the Rhomboidal Restricted Six-Body Problem Adv. Astron. (IF 1.4) Pub Date : 2021-07-01 M. A. R. Siddique, A. R. Kahsif, M. Shoaib, S. Hussain
We discuss the restricted rhomboidal six-body problem (RR6BP), which has four positive masses at the vertices of the rhombus, and the fifth mass is at the intersection of the two diagonals. These masses always move in rhomboidal CC with diagonals and . The sixth body, having a very small mass, does not influence the motion of the five masses, also called primaries. The masses of the primaries are and
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Trends in Architecture and Middleware of Radio Telescope Control System Adv. Astron. (IF 1.4) Pub Date : 2021-06-29 Jun Li, Na Wang, Zhiyong Liu, Yining Song, Ning Li, Lingming Xu, Jili Wang
The control system is the central control unit of the radio telescope. It is used to monitor, control, coordinate, and manage software and hardware systems so as to satisfy the requirements of high-precision control in astronomical observation of radio telescope. The control system architecture is the foundation for the implementation of the control system, which determines the stability, scalability
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On the Mass Distribution of Fragments of an Asteroid Disrupted in the Earth’s Atmosphere Adv. Astron. (IF 1.4) Pub Date : 2021-06-24 Irina G. Brykina, Lidia A. Egorova
To model the interaction with the atmosphere of fragments of a disrupted asteroid, which move independently of each other, it is necessary to know their mass distribution. In this regard, an analogy is drawn with fragmentation in high-speed impact experiments performed to simulate the disruption of asteroids at their collisions in outer space. Based on the results of impact experiments and assuming
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Traversable Wormholes Existence in Gravity Involving Trace-Squared Term with Nonexotic Matter Adv. Astron. (IF 1.4) Pub Date : 2021-06-19 M. Zubair, Quratulien Muneer, Saira Waheed
In Einstein’s relativity theory, the existence of traversable wormholes requires the involvement of exotic matter which violates the null energy condition (NEC). Our aim, in this article, is to construct wormhole solutions with the nonexotic matter. To achieve this, we choose an interesting gravitational framework of theory which contains a quadratic term of energy-momentum tensor trace and a well-known
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An Analytical Computational Algorithm for Solving a System of Multipantograph DDEs Using Laplace Variational Iteration Algorithm Adv. Astron. (IF 1.4) Pub Date : 2021-06-14 Mohamed S. M. Bahgat, A. M. Sebaq
In this research, an approximation symbolic algorithm is suggested to obtain an approximate solution of multipantograph system of type delay differential equations (DDEs) using a combination of Laplace transform and variational iteration algorithm (VIA). The corresponding convergence results are acquired, and an efficient algorithm for choosing a feasible Lagrange multiplier is designed in the solving
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Small Mars Mission Architecture Study Adv. Astron. (IF 1.4) Pub Date : 2021-06-10 Claire E. Parfitt, Adam G. McSweeney, Lisa De Backer, Csilla Orgel, Andrew J. Ball, Michael Khan, Sanjay Vijendran
While the vast majority of ESA’s funding for Mars exploration in the 2020s is planned to be invested in ExoMars and Mars Sample Return, there is an interest to assess the possibility of implementing a small mission to Mars in parallel with, or soon after, the completion of the MSR programme. A study was undertaken in the Concurrent Design Facility at ESA ESTEC to assess low-cost mission architectures
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Spectral Feature Extraction Using Partial and General Method Adv. Astron. (IF 1.4) Pub Date : 2021-06-08 Bin Jiang, Xi Fang, Yang Liu, Xingzhu Wang, Jie Liu
With the rapid growth in astronomical spectra produced by large sky survey telescopes, traditional manual classification processes can no longer fulfill the requirements of precision and efficiency of spectral classification. There is an urgent need to employ machine learning approaches to conduct automated spectral classification tasks. Feature extraction is a critical step which has a great impact
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A Quantized Hill’s Dynamical System Adv. Astron. (IF 1.4) Pub Date : 2021-06-07 Elbaz I. Abouelmagd, Vassilis S. Kalantonis, Angela E. Perdiou
In this paper, we present a modified version of Hill’s dynamical system that is called the quantized Hill’s three-body problem in the sense that the equations of motion for the classical Hill’s problem are now derived under the effects of quantum corrections. To do so, the position variables and the parameters that correspond to the quantum corrections of the respective quantized three-body problem
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Research on Mount Wilson Magnetic Classification Based on Deep Learning Adv. Astron. (IF 1.4) Pub Date : 2021-06-07 Yuanbo He, Yunfei Yang, Xianyong Bai, Song Feng, Bo Liang, Wei Dai
The Mount Wilson magnetic classification of sunspot groups is thought to be meaningful to forecast flares’ eruptions. In this paper, we adopt a deep learning method, CornerNet-Saccade, to perform the Mount Wilson magnetic classification of sunspot groups. It includes three stages, generating object locations, detecting objects, and merging detections. The key technologies consist of the backbone as
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A Numerical Approach to Study Ablation of Large Bolides: Application to Chelyabinsk Adv. Astron. (IF 1.4) Pub Date : 2021-03-27 Josep M. Trigo-Rodríguez, Joan Dergham, Maria Gritsevich, Esko Lyytinen, Elizabeth A. Silber, Iwan P. Williams
In this study, we investigate the ablation properties of bolides capable of producing meteorites. The casual dashcam recordings from many locations of the Chelyabinsk superbolide associated with the atmospheric entry of an 18 m in diameter near-Earth object (NEO) have provided an excellent opportunity to reconstruct its atmospheric trajectory, deceleration, and heliocentric orbit. In this study, we
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Modification of Gravitational Field Equation due to Invariance of Light Speed and New System of Universe Evolution Adv. Astron. (IF 1.4) Pub Date : 2021-03-20 Jian Liang Yang
We make a systematic examination of the basic theory of general relativity and reemphasize the meaning of coordinates. Firstly, we prove that Einsteinʼs gravitational field equation has the light speed invariant solution and black holes are not an inevitable prediction of general relativity. Second, we show that the coupling coefficient of the gravitational field equation is not unique and can be modified
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Conformable Fractional Models of the Stellar Helium Burning via Artificial Neural Networks Adv. Astron. (IF 1.4) Pub Date : 2021-03-16 Emad A.-B. Abdel-Salam, Mohamed I. Nouh, Yosry A. Azzam, M. S. Jazmati
The helium burning phase represents the second stage that the star used to consume nuclear fuel in its interior. In this stage, the three elements, carbon, oxygen, and neon, are synthesized. The present paper is twofold: firstly, it develops an analytical solution to the system of the conformable fractional differential equations of the helium burning network, where we used, for this purpose, the series
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Assessment of Near-Earth Asteroid Deflection Techniques via Spherical Fuzzy Sets Adv. Astron. (IF 1.4) Pub Date : 2021-03-08 M. Fernández-Martínez, J. M. Sánchez-Lozano
Extensions of fuzzy sets to broader contexts constitute one of the leading areas of research in the context of problems in artificial intelligence. Their aim is to address decision-making problems in the real world whenever obtaining accurate and sufficient data is not a straightforward task. In this way, spherical fuzzy sets were recently introduced as a step beyond to modelize such problems more
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Bouncing Cosmology in Gravity with Logarithmic Trace Term Adv. Astron. (IF 1.4) Pub Date : 2021-03-03 M. Farasat Shamir
This study is devoted to explore bouncing cosmology in the context of theory of gravity. For this purpose, a Gauss–Bonnet cosmological model with logarithmic trace term is considered. In particular, the possibility of obtaining bouncing solutions by considering two equations of state parameters is investigated. A graphical analysis is provided for analyzing the obtained bouncing solutions. The energy
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Fault Tolerance for Active Surface System with Actuator Faults Adv. Astron. (IF 1.4) Pub Date : 2021-02-26 Danqing Zhang, Binbin Xiang, Aili Yusup, Na Wang, Guljaina Kazezkhan
The QiTai Radio Telescope (QTT) will be equipped with the active surface adjustment system (ASAS) to correct the main reflector deformation caused by environmental loading. In order to guarantee the stability and performance of the active surface system under fault conditions, it is necessary to adopt the fault-tolerant method when actuator faults have occurred. In this paper, a fault control method
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The Stability of Certain Motion of a Charged Gyrostat in Newtonian Force Field Adv. Astron. (IF 1.4) Pub Date : 2021-02-22 A. A. Elmandouh, Fatimah H. Alsaad
This work aims to study the stability of certain motions of a rigid body rotating about its fixed point and carrying a rotor that rotates with constant angular velocity about an axis parallel to one of the principal axes. This motion is presumed to take place due to the combined influence of the magnetic field and the Newtonian force field. The equations of motion are deduced, and moreover, they are
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Impacts of Poynting–Robertson Drag and Dynamical Flattening Parameters on Motion around the Triangular Equilibrium Points of the Photogravitational ER3BP Adv. Astron. (IF 1.4) Pub Date : 2021-02-11 Aishetu Umar, Aminu Abubakar Hussain
Using an analytical and numerical study, this paper investigates the equilibrium state of the triangular equilibrium points of the Sun-Earth system in the frame of the elliptic restricted problem of three bodies subject to the radial component of Poynting–Robertson (P–R) drag and radiation pressure factor of the bigger primary as well as dynamical flattening parameters of both primary bodies (i.e.
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Chaotic Oscillation of Satellite due to Aerodynamic Torque Adv. Astron. (IF 1.4) Pub Date : 2021-02-10 Rashmi Bhardwaj, Mohammad Sajid
This study presents the chaotic oscillation of the satellite around the Earth due to aerodynamic torque. The orbital plane of the satellite concurs is same as the tropical plane of Earth. The half-width of riotous separatrix is assessed utilizing Chirikov’s measure. Variety of boundary techniques shows that streamlined force boundary (ɛ), unpredictability of circle (e), and mass-proportion (ω0) convert
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A Generic Embedding Class-I Model via Karmarkar Condition in Gravity Adv. Astron. (IF 1.4) Pub Date : 2021-02-09 M. Zubair, Saira Waheed, Hina Javaid
In the present work, we investigate the existence of compact star model in the background of gravity theory, where represents the Ricci scalar and refers to the energy-momentum tensor trace. Here, we use Karmarkar condition for the interior stellar setup so that a complete and precise model following the embedding class-I strategy can be obtained. For this purpose, we assume anisotropic matter contents
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Scaling Laws in the Stellar Mass Distribution and the Transition to Homogeneity Adv. Astron. (IF 1.4) Pub Date : 2021-02-08 José Gaite
We present a new statistical analysis of the large-scale stellar mass distribution in the Sloan Digital Sky Survey (data release 7). A set of volume-limited samples shows that the stellar mass of galaxies is concentrated in a range of galaxy luminosities that is very different from the range selected by the usual analysis of galaxy positions. Nevertheless, the two-point correlation function is a power-law
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Magnetohydrodynamic Fluid Flow due to an Unsteady Stretching Sheet with Thermal Radiation, Porous Medium, and Variable Heat Flux Adv. Astron. (IF 1.4) Pub Date : 2021-01-31 Ahmed M. Megahed, Nourhan I. Ghoneim, M. Gnaneswara Reddy, Mostafa El-Khatib
A shooting method has been introduced for determining the numerical solution of the ordinary differential equations which describe the Newtonian magnetohydrodynamic laminar fluid flow due to an unsteady stretching sheet together with the presence of thermal radiation and variable heat flux. The variable viscosity and variable conductivity are taken into consideration. Absence of magnetic field in some
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Compact Stars Admitting Noether Symmetries in Energy-Momentum Squared Gravity Adv. Astron. (IF 1.4) Pub Date : 2021-01-26 M. Sharif,M. Zeeshan Gul
This paper investigates the geometry of compact stellar objects through the Noether symmetry approach in the energy-momentum squared gravity. This newly developed theory overcomes the problems of big bang singularity and provides the viable cosmological consequences in the early time universe. Moreover, its implications occur in high curvature regime where the deviations of energy-momentum squared
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Model of Charged Anisotropic Strange Stars in Minimally Coupled Gravity Adv. Astron. (IF 1.4) Pub Date : 2021-01-04 H. Nazar, G. Abbas
In the present article, we have investigated a new family of nonsingular solutions of static relativistic compact sphere which incorporates the characteristics of anisotropic fluid and electromagnetic field in the context of minimally coupled theory of gravity. The strange matter bag model equation of state (EoS) has been considered along with the usual forms of the Karori–Barua metric potentials.
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Evolution of Periodic Orbits within the Frame of Formation Satellites Adv. Astron. (IF 1.4) Pub Date : 2020-12-21 Elbaz I. Abouelmagd, Mitali J. Doshi, Niraj M. Pathak
In the framework of formation satellites, the periodic orbits of deputy satellite are analyzed when the chief satellite is moving in an elliptical orbit. This analysis is developed on 1- to 10-loop periodic orbits of the deputy satellite. These orbits along with their associated loops are discussed under some specific initial position sets. The effects of different initial velocities, initial true
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Motion of the Infinitesimal Variable Mass in the Generalized Circular Restricted Three-Body Problem under the Effect of Asteroids Belt Adv. Astron. (IF 1.4) Pub Date : 2020-12-18 Ferdaous Bouaziz-Kellil
The present paper deals with the study of the motion’s properties of the infinitesimal variable mass body moving in the same orbital plan as two massive bodies (considered as primaries). It is assumed that the massive bodies have radiating effects, have oblate shapes, and are moving in circular orbits around their common center of mass. Using the procedures established by Singh and Abouelmagd, we determined
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Quartic Integral in Rigid Body-Gyrostat Dynamics Adv. Astron. (IF 1.4) Pub Date : 2020-12-11 C. Mnasri, A. A. Elmandouh
In this work, we investigate the problem of constructing new integrable problems in the dynamics of the rigid body rotating about its fixed point as results of the effect of a combination of potential and gyroscopic forces possessing a common symmetry axis. We introduce two new integrable problems in a rigid body dynamics that generalize some integrable problems in this field, known by names of Chaplygin
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New Treatment of the Rotary Motion of a Rigid Body with Estimated Natural Frequency Adv. Astron. (IF 1.4) Pub Date : 2020-12-07 A. I. Ismail
In this paper, the problem of the motion of a rigid body about a fixed point under the action of a Newtonian force field is studied when the natural frequency . This case of singularity appears in the previous works and deals with different bodies which are classified according to the moments of inertia. Using the large parameter method, the periodic solutions for the equations of motion of this problem
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Light Speed Invariant Solution and Its Enlightenment of Field Equation of General Relativity Adv. Astron. (IF 1.4) Pub Date : 2020-11-29 Jian Liang Yang
A systematic examination of the basic theory of general relativity is made, the meaning of coordinates again is emphasized, the confusion caused by unclear meaning of coordinates in the past is corrected, and the expression of the theory is made more accurate. Firstly, the equation of Einstein’s gravitational field is solved in the usual coordinate system, the existence of light speed invariant solution
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Wormhole Models and Energy Conditions in Gravity with the Hu–Sawicki Model Adv. Astron. (IF 1.4) Pub Date : 2020-11-23 Ouziala Ikram, G. Mustafa
In this recent study, we shall investigate the wormhole models with a Hu–Sawicki model in the framework of gravity. Spherically static symmetric space-time is considered to construct wormhole models with the anisotropic fluid distribution. The traceless matter is discussed by imposing a particular equation of state. To address the important conditions of the shape function of the wormhole geometry
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Isotropic Gravastar Model in Rastall Gravity Adv. Astron. (IF 1.4) Pub Date : 2020-11-16 G. Abbas, K. Majeed
In the present paper, we have introduced a new model of gravastar with an isotropic matter distribution in Rastall gravity by the Mazur–Mottola (2004) mechanism. Mazur–Mottola approach is about the construction of gravastar which is predicted as an alternative to black hole. By following this convention, we define gravastar in the form of three phases. The first one is an interior phase which has negative
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Approximate Analytical Three-Dimensional Multiple Time Scales Solution to a Circular Restricted Three-Body Problem Adv. Astron. (IF 1.4) Pub Date : 2020-11-11 Fabao Gao, Yongqing Wang
We illustrate the chaotic nature of the circular restricted three-body problem from the perspective of the bifurcation diagram with respect to the mass ratio parameter. Moreover, it is shown that when the frequency ratio in different directions of the classical problem is irrational, it has the quasiperiodic characteristics. In addition, a three-dimensional approximate solution to this problem under