A.G. Magner , S.P. Maydanyuk , A. Bonasera , H. Zheng , T. Depastas , A.I. Levon , U.V. Grygoriev
{"title":"有效表面近似下TOV方程和核天体物理学的细端修正","authors":"A.G. Magner , S.P. Maydanyuk , A. Bonasera , H. Zheng , T. Depastas , A.I. Levon , U.V. Grygoriev","doi":"10.1016/j.nuclphysa.2025.123239","DOIUrl":null,"url":null,"abstract":"<div><div>The macroscopic model for a neutron star (NS) as a liquid drop at the equilibrium is used to extend the Tolman-Oppenheimer-Volkoff (TOV) equations taking into account the gradient terms responsible for the system surface. The parameters of the Schwarzschild metric in the spherical case are found with these surface corrections to the known leading (zero) order of the leptodermic approximation <span><math><mi>a</mi><mo>/</mo><mi>R</mi><mo><</mo><mo><</mo><mn>1</mn></math></span>, where <em>a</em> is the NS effective-surface (ES) thickness, and <em>R</em> is the effective NS radius. The energy density <span><math><mi>E</mi></math></span> is considered in a general form including the functions of the particle number density and of its gradient terms. The macroscopic gravitational component <span><math><mi>Φ</mi><mo>(</mo><mi>ρ</mi><mo>)</mo></math></span> of the energy density is taken into account in the simplest form as expansion in powers of <span><math><mi>ρ</mi><mo>−</mo><mover><mrow><mi>ρ</mi></mrow><mo>‾</mo></mover></math></span>, where <span><math><mover><mrow><mi>ρ</mi></mrow><mo>‾</mo></mover></math></span> is the saturation density, up to second order, in terms of its contributions to the separation particle energy and incompressibility. Density distributions <em>ρ</em> across the NS ES in the normal direction to the ES, which are derived in the simple analytical form at the same leading approximation, was used for the derivation of the modified TOV (MTOV) equations by accounting for their NS surface corrections. The MTOV equations are analytically solved at first order and the results are compared with the standard TOV approach of the zero order.</div></div>","PeriodicalId":19246,"journal":{"name":"Nuclear Physics A","volume":"1064 ","pages":"Article 123239"},"PeriodicalIF":2.5000,"publicationDate":"2025-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Leptodermic corrections to the TOV equations and nuclear astrophysics within the effective surface approximation\",\"authors\":\"A.G. Magner , S.P. Maydanyuk , A. Bonasera , H. Zheng , T. Depastas , A.I. Levon , U.V. Grygoriev\",\"doi\":\"10.1016/j.nuclphysa.2025.123239\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><div>The macroscopic model for a neutron star (NS) as a liquid drop at the equilibrium is used to extend the Tolman-Oppenheimer-Volkoff (TOV) equations taking into account the gradient terms responsible for the system surface. The parameters of the Schwarzschild metric in the spherical case are found with these surface corrections to the known leading (zero) order of the leptodermic approximation <span><math><mi>a</mi><mo>/</mo><mi>R</mi><mo><</mo><mo><</mo><mn>1</mn></math></span>, where <em>a</em> is the NS effective-surface (ES) thickness, and <em>R</em> is the effective NS radius. The energy density <span><math><mi>E</mi></math></span> is considered in a general form including the functions of the particle number density and of its gradient terms. The macroscopic gravitational component <span><math><mi>Φ</mi><mo>(</mo><mi>ρ</mi><mo>)</mo></math></span> of the energy density is taken into account in the simplest form as expansion in powers of <span><math><mi>ρ</mi><mo>−</mo><mover><mrow><mi>ρ</mi></mrow><mo>‾</mo></mover></math></span>, where <span><math><mover><mrow><mi>ρ</mi></mrow><mo>‾</mo></mover></math></span> is the saturation density, up to second order, in terms of its contributions to the separation particle energy and incompressibility. Density distributions <em>ρ</em> across the NS ES in the normal direction to the ES, which are derived in the simple analytical form at the same leading approximation, was used for the derivation of the modified TOV (MTOV) equations by accounting for their NS surface corrections. The MTOV equations are analytically solved at first order and the results are compared with the standard TOV approach of the zero order.</div></div>\",\"PeriodicalId\":19246,\"journal\":{\"name\":\"Nuclear Physics A\",\"volume\":\"1064 \",\"pages\":\"Article 123239\"},\"PeriodicalIF\":2.5000,\"publicationDate\":\"2025-09-05\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Nuclear Physics A\",\"FirstCategoryId\":\"101\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S0375947425002258\",\"RegionNum\":4,\"RegionCategory\":\"物理与天体物理\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"PHYSICS, NUCLEAR\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Nuclear Physics A","FirstCategoryId":"101","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0375947425002258","RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"PHYSICS, NUCLEAR","Score":null,"Total":0}
Leptodermic corrections to the TOV equations and nuclear astrophysics within the effective surface approximation
The macroscopic model for a neutron star (NS) as a liquid drop at the equilibrium is used to extend the Tolman-Oppenheimer-Volkoff (TOV) equations taking into account the gradient terms responsible for the system surface. The parameters of the Schwarzschild metric in the spherical case are found with these surface corrections to the known leading (zero) order of the leptodermic approximation , where a is the NS effective-surface (ES) thickness, and R is the effective NS radius. The energy density is considered in a general form including the functions of the particle number density and of its gradient terms. The macroscopic gravitational component of the energy density is taken into account in the simplest form as expansion in powers of , where is the saturation density, up to second order, in terms of its contributions to the separation particle energy and incompressibility. Density distributions ρ across the NS ES in the normal direction to the ES, which are derived in the simple analytical form at the same leading approximation, was used for the derivation of the modified TOV (MTOV) equations by accounting for their NS surface corrections. The MTOV equations are analytically solved at first order and the results are compared with the standard TOV approach of the zero order.
期刊介绍:
Nuclear Physics A focuses on the domain of nuclear and hadronic physics and includes the following subsections: Nuclear Structure and Dynamics; Intermediate and High Energy Heavy Ion Physics; Hadronic Physics; Electromagnetic and Weak Interactions; Nuclear Astrophysics. The emphasis is on original research papers. A number of carefully selected and reviewed conference proceedings are published as an integral part of the journal.