International Journal of Astrophysics and Space Science最新文献_第2页

Analytical Models for Quark Stars with Van Der Waals Modified Equation of State 范德华修正状态方程下夸克星的解析模型

International Journal of Astrophysics and Space Science Pub Date : 2019-10-24 DOI: 10.11648/j.ijass.20190705.11

M. Malaver, Prof Dr Hamed Daei Kasmaei

{"title":"Analytical Models for Quark Stars with Van Der Waals Modified Equation of State","authors":"M. Malaver, Prof Dr Hamed Daei Kasmaei","doi":"10.11648/j.ijass.20190705.11","DOIUrl":"https://doi.org/10.11648/j.ijass.20190705.11","url":null,"abstract":"Stellar models consisting of spherically symmetric distribution of charged matter locally anisotropic in strong gravitational fields have been widely considered in the frame of general relativity. These investigations require the generation of exact models through the resolution of the Einstein-Maxwell system of equations. The presence of charge produces values for redshifts, luminosity and mass for the stars different in relation to neutral matter. Some applications for dense charged matter we have them in the description of quark stars, spheres with linear or non-linear equation of state, hybrid stars and accreting process in compact objects where the matter acquires large amounts of electric charge. In this paper, we studied the behavior of relativistic compact objects with anisotropic matter distribution considering Van der Waals modified equation of state proposed in 2013 for Malaver and a gravitational potential Z(x) that depends on an adjustable parameter α in order to integrate analytically the field equations. They generalize the ideal gas law based on plausible reasons that real gases do not act ideally. New exact solutions of the Einstein-Maxwell system are generated and the physical variables as the energy density, radial pressure, mass function, anisotropy factor and the metric functions are written in terms of elementary and polynomial functions. We obtained expressions for radial pressure, density and mass of the stellar object physically acceptable with two different values of the adjustable parameter. The proposed models satisfy all physical features of a realistic star.","PeriodicalId":414846,"journal":{"name":"International Journal of Astrophysics and Space Science","volume":"79 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114093511","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

Comparison of Global Vertical Total Electron Content from Various Global Data Centers 全球不同数据中心的全球垂直总电子含量比较

International Journal of Astrophysics and Space Science Pub Date : 2019-10-23 DOI: 10.11648/j.ijass.20190704.12

Shambel Gizachew, Belay Sitotaw, G. Tsidu

引用次数: 0

Gravitational and Electromagnetic Force Unification, Using a Statistical Analysis from a Signature of Supernova Explosions 引力和电磁力的统一，利用超新星爆炸特征的统计分析

International Journal of Astrophysics and Space Science Pub Date : 2019-09-06 DOI: 10.11648/J.IJASS.20190703.11

J. N. Aniezi, G. Anene

{"title":"Gravitational and Electromagnetic Force Unification, Using a Statistical Analysis from a Signature of Supernova Explosions","authors":"J. N. Aniezi, G. Anene","doi":"10.11648/J.IJASS.20190703.11","DOIUrl":"https://doi.org/10.11648/J.IJASS.20190703.11","url":null,"abstract":"Unification of gravitational and electromagnetic interactions was done using statistical method. Cosmic ray intensity as a signature from supernova explosions was used to carry out some estimation. These primary cosmic rays are charged particles with an accelerating mechanism, probably electromagnetic; and because their charge is what interacts with matter and produces the effects that we can easily see here on earth. We estimated the values of the electromagnetic interaction and gravitational force of interaction of the source using previous known relations. We were able to obtain a regression equation; with a positive and strong correlation coefficient. Fa depicts the gravitational interaction and Umaa is the electromagnetic interaction. The results suggestively indicate that gravitational and electromagnetic interactions are related. The result indicates that moving charges and moving masses provide an analogy of gravitational and electromagnetic fields, which support the concept of a gravito-magnetic force. It has solved to some extend the speculations about the development in an attempt to unify the interactions of particles; and even to incorporate gravity in the “theory of everything”. Thus, the unification of forces using the explosion mechanism and gravitational waves in core-collapse supernovae has become a reality.","PeriodicalId":414846,"journal":{"name":"International Journal of Astrophysics and Space Science","volume":"117 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115017963","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

New Models of Dark Energy Stars with Charge Distributions 具有电荷分布的暗能量恒星新模型

International Journal of Astrophysics and Space Science Pub Date : 2019-09-02 DOI: 10.11648/J.IJASS.20190702.12

M. Malaver, M. Esculpi, M. Govender

{"title":"New Models of Dark Energy Stars with Charge Distributions","authors":"M. Malaver, M. Esculpi, M. Govender","doi":"10.11648/J.IJASS.20190702.12","DOIUrl":"https://doi.org/10.11648/J.IJASS.20190702.12","url":null,"abstract":"In this paper, we have obtained a relativistic and spherically symmetric stellar configuration that describes an anisotropic fluid with a charge distribution that represents a potential model for a dark energy star and we specify particular forms in the gravitational potential and the electric field intensity which allows solve the Einstein-Maxwell field equations. The reason for proposing this model originates from the evidence that recent observational findings suggest that the universe has an accelerated cosmic expansion and the model of dark energy star is one of the most reasonable explanations of this phenomena. The field equations are integrated analytical and new stellar configurations are obtained are analyzed. For each these solutions we found that the radial pressure, the anisotropy factor, energy density, metric coefficients, mass function, charge density are regular and well behaved in the stellar interior. With the new solutions can be developed models of dark energy stars physically acceptable where the causality condition is not satisfied or the strong energy condition is violated. This model has a great application in the study of the fundamental theories of physics and cosmology. Several independent observations indicate that the greater part of the total energy density of the universe is in the form of dark energy and the rest in the form of nonbaryonic cold dark matter particles, but which have never been detected.","PeriodicalId":414846,"journal":{"name":"International Journal of Astrophysics and Space Science","volume":"47 1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123521367","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 5

Study of Response of Extreme Meso-Scale Field-Aligned Current to Interplanetary Magnetic Field Components BX, BY and BZ During Geomagnetic Storm 地磁风暴期间极端中尺度场向电流对行星际磁场分量BX、BY和BZ的响应研究

International Journal of Astrophysics and Space Science Pub Date : 2019-08-07 DOI: 10.11648/J.IJASS.20190701.11

Adero Ochieng Awuor, Paul Baki, O. Joseph, P. Cilliers, P. Kotzé

{"title":"Study of Response of Extreme Meso-Scale Field-Aligned Current to Interplanetary Magnetic Field Components BX, BY and BZ During Geomagnetic Storm","authors":"Adero Ochieng Awuor, Paul Baki, O. Joseph, P. Cilliers, P. Kotzé","doi":"10.11648/J.IJASS.20190701.11","DOIUrl":"https://doi.org/10.11648/J.IJASS.20190701.11","url":null,"abstract":"The influence of IMF components on meso-scale field-aligned currents (FACs) is investigated with an aim to establish how different IMF components influence the occurrence and distribution of FACs. The field-aligned currents (FACs) are calculated from the curl of the Ampere’s law to the magnetic field recorded by CHAMP satellite during 24 major geomagnetic storms. To determine the field-aligned currents at extreme mesoscale range ∼150 - 250 km, a low-pass filter to FACs with a cutoff period of 20s is applied. The peak-to-peak amplitude of FAC density, with the maximum difference ≤ 30 MLAT, is determined and used to define the FAC range. The results indicate high occurrence of FACs centered about IMF ≈ 0, for large values of Dst. The magnitude of FACs is in general affected by all the three IMF components, alongside other ionospheric factors such as solar wind speed and density. Magnetic reconnection, under -BZ is a major FACs drivers and is significant in the dayside northern hemisphere. The reconnection is not symmetric in both hemispheres. We find a possible electrodynamic similarity between the dayside northern hemisphere and nightside southern hemisphere, prominent along BX when BZ is negative. This interesting observation can further be investigated.","PeriodicalId":414846,"journal":{"name":"International Journal of Astrophysics and Space Science","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132766203","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Density, Alternative Determinant of Star Formation Efficiency of the Milky Way GMCs: Core Reason for Low Star Formation Efficiency 密度，银河系巨噬星云恒星形成效率的替代决定因素:恒星形成效率低的核心原因

International Journal of Astrophysics and Space Science Pub Date : 1900-01-01 DOI: 10.11648/j.ijass.20210903.12

Okezuonu Patrick Chinedu, Ogwo Jemima Ngozi

{"title":"Density, Alternative Determinant of Star Formation Efficiency of the Milky Way GMCs: Core Reason for Low Star Formation Efficiency","authors":"Okezuonu Patrick Chinedu, Ogwo Jemima Ngozi","doi":"10.11648/j.ijass.20210903.12","DOIUrl":"https://doi.org/10.11648/j.ijass.20210903.12","url":null,"abstract":": The overall efficiency with which Milky Way Giant Molecular Clouds (GMCs) is forming stars was determined by deriving an equation using density of cloud (i.e. stellar density/ total cloud density), which is the core parameter that determines star formation other than the mass of cloud, and comparing with mass (i.e. stellar mass/ total gas mass) as was propounded by previous researchers, to ascertain the reasons the observed star formation efficiency of Milky Way Giant Molecular Clouds ( (cid:1) ) is low. This will aid understanding the physical factors behind the formation of stars from interstellar gas and develop a predictive theory of star formation and evolution of galaxies. A total of 191 star formation complexes-giant molecular cloud (SFC-GMC) complexes was used in estimating the following cloud parameters: density as 93.8218 solar mass/parsec squared, average stellar density as 2.67872 solar mass/parsec squared, average luminosity as 9.87E24 solar luminosity, average effective temperature as 498,647 solar temperature, average stellar radius as 51.4522 parsec and average cloud radius as 325507 parsec as well as the total mass in stars M (cid:6) harbored by the individual clouds (20,831 solar mass), which was inferred from Wilkinson Microwave Anisotropy probe (WMAP) free-free. Finally, the overall efficiency with which Milky Way Giant Molecular Clouds is forming star gave 0.0289573 which is less than the previous estimate as 0.030849, showing that not all the masses of the cloud were present at the end of the star formation, and this reduction in mass are caused by magnetic field, supersonic turbulence, self-regulation and unbound states of its internal structure, which are the reasons the observed star formation efficiencies are low.","PeriodicalId":414846,"journal":{"name":"International Journal of Astrophysics and Space Science","volume":"70 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123526927","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

On the Extend of Eddington Ratio and Accretion Rate in Seyfert 1 and Hidden Broad Line Region Seyfert 2 Galaxies 塞弗特1星系和塞弗特2隐宽线区中爱丁顿比和吸积率的扩展

International Journal of Astrophysics and Space Science Pub Date : 1900-01-01 DOI: 10.11648/j.ijass.20210904.11

Nwankwo Ifeanyi Francis, Ogwo Jemima Ngozi

引用次数: 0

Analysis of Earth-Uranus Direct-Transfer Trajectory for Optimal Delta-V Using Lambert’s Problem 用Lambert问题分析最优Delta-V的地球-天王星直接传递轨迹

International Journal of Astrophysics and Space Science Pub Date : 1900-01-01 DOI: 10.11648/j.ijass.20221001.12

Gisa Geoson Suseela, Yadu Krishnan Sukumarapillai, Hariprasad Thimmegowda, Pavan Kalyan Devaiah, M. Nagendra, Tamore Silviya Dhiraj

{"title":"Analysis of Earth-Uranus Direct-Transfer Trajectory for Optimal Delta-V Using Lambert’s Problem","authors":"Gisa Geoson Suseela, Yadu Krishnan Sukumarapillai, Hariprasad Thimmegowda, Pavan Kalyan Devaiah, M. Nagendra, Tamore Silviya Dhiraj","doi":"10.11648/j.ijass.20221001.12","DOIUrl":"https://doi.org/10.11648/j.ijass.20221001.12","url":null,"abstract":": The Ice Giants may become a sought-after destination in the coming decades as researchers aim to have a better awareness of our Solar system- its origins and growth. The interplanetary trajectory optimization is an important aspect of the analysis of a mission to Uranus. This study investigates possible interplanetary paths to Uranus in the 2022-2030 timeframe. It provides a preliminary estimate of fuel consumption in units of ∆V for various mission durations. A variety of approaches can be used to travel from Earth to another planet. It is conceivable to use a direct transfer route with two engine burns, one at a parking orbit around the Earth and the other to capture around the target planet. This article emphasizes a direct transfer trajectory analysis towards Uranus using Lambert’s problem. Different lambert arcs were considered for the direct transfer. Variations of excess velocities at arrival and departure for various time-of-flight were obtained. The ceiling of the time-of-flight was fixed as 16.5 years by performing a Hohmann transfer. The minimum ∆V was obtained for various time-of-flight ranging from 8.5 years to 16.5 years. The ideal ∆V obtained during the fixed timeframe lies between 6.87 km/s and 7.98 km/s. The minimum value of ∆V was observed for the time-of-flight of 13.5 years.","PeriodicalId":414846,"journal":{"name":"International Journal of Astrophysics and Space Science","volume":"88 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132953912","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Spherical Symmetric Kink-Like Configurations of Spinor and Gravitational Fields 旋子场和引力场的球对称类键配置

International Journal of Astrophysics and Space Science Pub Date : 1900-01-01 DOI: 10.11648/J.IJASS.20200804.11

J. Edou, A. Adomou, Valerie I. S. Hontinfinde, S. Massou

{"title":"Spherical Symmetric Kink-Like Configurations of Spinor and Gravitational Fields","authors":"J. Edou, A. Adomou, Valerie I. S. Hontinfinde, S. Massou","doi":"10.11648/J.IJASS.20200804.11","DOIUrl":"https://doi.org/10.11648/J.IJASS.20200804.11","url":null,"abstract":"The present research work deals with an extension of a previous work [Exact Soliton-like spherical symmetric solutions of the Heisenberg-Ivanenko type nonlinear spinor field equation in gravitational theory, Journal of Applied Mathematics and Physics, 2020, 8, 1236-1254] to Spherical Symmetric Kink-Like Configurations of Spinor and Gravitational Fields. We have obtained exact kink-like static spherical symmetric solutions to the self-consistent system of spinor and gravitational fields equations. The Einstein’s field equation shave been solved by the Liouville method. The principal difference between kink soliton with antikink soliton has been established. The nonlinear terms in the lagrangian are arbitrary functions F(IS) depending on the invariant IS = S2= ( )2. It is shown that the initial set of the Einstein and spinor field equations have regular solutions with a localized energy density of the spinor field only if m = 0 (m is the mass parameter in the spinor field equations). Equations with polynomial nonlinearities are thoroughly scrutinized. Let us emphasize that the spinor field with polynomial nonlinearities has a regular solutions with localized, positive and alternating energy density and finite total energy. In addition, the total charge and the total spin are also finte. We have also obtained exact solutions to the linear spinor field equations. We remarked that in this case soliton-like solutions are absent. Furthermore, we note that the properties of regular localized solutions depend on the symmetry and the nonlinear terms in the lagrangian of the self-consistent system of gravitational and spinor fields.","PeriodicalId":414846,"journal":{"name":"International Journal of Astrophysics and Space Science","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126214113","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Interstellar Medium Parameters in Front of the External Bow Shock 外弓激波前星际介质参数

International Journal of Astrophysics and Space Science Pub Date : 1900-01-01 DOI: 10.11648/j.ijass.20190702.11

Pavel Alexandrovich Sedykh

引用次数: 0