Hybrid Stars with Color Superconducting Cores in an Extended FCM Model
Hybrid Stars with Color Superconducting Cores in an Extended FCM Model
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DOI：
10.3390/universe7100370
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发表时间：
2021-10
期刊：
影响因子：
2.9
通讯作者：
Daniela Curin;I. F. Ranea-Sandoval;M. Mariani;M. Orsaria;F. Weber
中科院分区：
文献类型：
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作者：
Daniela Curin;I. F. Ranea-Sandoval;M. Mariani;M. Orsaria;F. Weber
我们研究的排斥矢量相互作用和色超导性对中子星结构的影响，使用扩展版本的场相关器方法（FCM）的夸克物质的描述。混合状态方程的构造使用麦克斯韦描述，假设一个尖锐的强子夸克相变。在平均场近似下，利用SW 4L核模型给出的参数，计算了密度相关的相对论性拉格朗日量的强子物质状态方程。该模型用σ、ω、ρ、σ* 和π介子描述重子之间的相互作用。夸克物质被假定为CFL或2SC+s色超导相。研究了超密物质中强子-夸克、夸克-夸克的序贯跃迁的可能性。观测数据有关的大质量的恒星，引力波事件，和NICER被用来约束扩展FCM模型的参数。成功的状态方程被用来探索混合星的质量半径关系，半径和潮汐形变。一个特别的重点在于调查的后果，夸克强子物质的缓慢或快速转换的稳定性和混合星的质量半径关系。我们发现，如果发生缓慢的转换，一个新的稳定的大质量恒星的分支将存在，其成员的半径是高达1.5公里小于那些相同质量的常规中子星。这类天体可能是GW 190425双星系统中恒星大质量天体的候选者。
We investigate the influence of repulsive vector interactions and color superconductivity on the structure of neutron stars using an extended version of the field correlator method (FCM) for the description of quark matter. The hybrid equation of state is constructed using the Maxwell description, which assumes a sharp hadron-quark phase transition. The equation of state of hadronic matter is computed for a density-dependent relativistic lagrangian treated in the mean-field approximation, with parameters given by the SW4L nuclear model. This model described the interactions among baryons in terms of σ, ω, ρ, σ*, and ϕ mesons. Quark matter is assumed to be in either the CFL or the 2SC+s color superconducting phase. The possibility of sequential (hadron-quark, quark-quark) transitions in ultra-dense matter is investigated. Observed data related to massive pulsars, gravitational-wave events, and NICER are used to constrain the parameters of the extended FCM model. The successful equations of state are used to explore the mass-radius relationship, radii, and tidal deformabilities of hybrid stars. A special focus lies on investigating consequences that slow or fast conversions of quark-hadron matter have on the stability and the mass-radius relationship of hybrid stars. We find that if slow conversion should occur, a new branch of stable massive stars would exist whose members have radii that are up to 1.5 km smaller than those of conventional neutron stars of the same mass. Such objects could be possible candidates for the stellar high-mass object of the GW190425 binary system.