We investigate the influence of the energy gap(Δ)of the color-flavor locked(CFL)quark phase on the bulk properties of hybrid stars.The relativistic mean field model is used for hadronic matter and the MIT bag model f...We investigate the influence of the energy gap(Δ)of the color-flavor locked(CFL)quark phase on the bulk properties of hybrid stars.The relativistic mean field model is used for hadronic matter and the MIT bag model for CFL quark matter.In our calculation results,we find that with the increase of the CFL energy gap there exists a transition behavior,which goes from the hadron star range through the transition range into the CFL quark star range.The observation data of PRS J1614-2230 are in the hadron star range(withΔ<40MeV).We also find that with hyperons the equation of state(EOS)for the hybrid star matter with the CFL quark matter core has a small change,which can be disregarded.展开更多
Influences of the bag constant on the properties of hybrid stars are investigated by using relativistic mean field theory and the MIT bag model to describe the hadron phase and quark phase in the interior of neutron s...Influences of the bag constant on the properties of hybrid stars are investigated by using relativistic mean field theory and the MIT bag model to describe the hadron phase and quark phase in the interior of neutron stars, respectively. Our results indicate that the onset of hadron-quark phase transition is put off and the appearance of hyperon species is increased with the increase in bag constant. As a result, the hybrid star equation of state for a mixed phase range stiffens whereas that of the quark phase range softens, and the gravitational mass as well as the corresponding radius of hybrid stars are increased obviously. The gravitational mass of a hybrid star is increased from 1.42 M （M is solar mass） to 1.63M and the corresponding radius is changed from 9.1 km to 12.2 km when the bag constant （B1/4） is increased from 170 MeV to 200 MeV. It is interesting to find that hybrid star equations of state become non-smooth when the TM2 parameter sets in the framework of relativistic mean field theory used to describe the hadronic matter, and consequently, the third family of compact stars appear in the mass-radius relations of hybrid stars in the narrow scope of the bag constant from 175 MeV to 180 MeV. These show that the choice of the bag constant in the MIT bag model has significant influence on the properties of hybrid stars.展开更多
The properties of hybrid stars are investigated in the framework of the relativistic mean field theory （RMFT） and an MIT bag model with density-dependent bag constant to describe the hadron phase （HP） and quark ph...The properties of hybrid stars are investigated in the framework of the relativistic mean field theory （RMFT） and an MIT bag model with density-dependent bag constant to describe the hadron phase （HP） and quark phase （QP）, respectively. We find that the density-dependent B（p） decreases with baryon density p; this decrement makes the strange quark matter become more energetically favorable than ever, which makes the threshold densities of the hadron-quark phase transition lower than those of the original bag constant case. In this case, the hyperon degrees of freedom can not be considered. As a result, the equations of state of a star in the mixed phase （MP） become softer whereas those in the QP become stiffer, and the radii of the star obviously decrease. This indicates that the extended MIT bag model is more suitable to describe hybrid stars with small radii.展开更多
文摘利用强子物质的相对论平均场理论和夸克物质的有效质量口袋模型,研究流夸克质量的选取对混合星性质的影响.结果表明,随着流夸克质量的增大,强子-夸克相变使密度变大,超子种类变多,混合相区域的状态方程变硬,中子星的最大质量及半径变大.当奇异流夸克质量由90 MeV增到200 MeV时,混合星最大质量由1.4M⊙增至1.63M⊙(M⊙=1.99×1030kg为太阳质量),半径由10.24 km增至11.64 km.
基金Supported by the National Natural Science Foundation of China under Grant Nos 10675024,11075063 and 11265009the National Found for Fostering Talents of Basic Science under Grant No J1103202.
文摘We investigate the influence of the energy gap(Δ)of the color-flavor locked(CFL)quark phase on the bulk properties of hybrid stars.The relativistic mean field model is used for hadronic matter and the MIT bag model for CFL quark matter.In our calculation results,we find that with the increase of the CFL energy gap there exists a transition behavior,which goes from the hadron star range through the transition range into the CFL quark star range.The observation data of PRS J1614-2230 are in the hadron star range(withΔ<40MeV).We also find that with hyperons the equation of state(EOS)for the hybrid star matter with the CFL quark matter core has a small change,which can be disregarded.
基金Supported by the National Natural Science Foundation of China (10275029, 10675054)Natural Science Foundation of Henan Education Department (2008A140009)+1 种基金Science Foundation of Nanyang Normal University (nytc2006k98)Natural Science Foundation of Henan Province (112300410187)
文摘Influences of the bag constant on the properties of hybrid stars are investigated by using relativistic mean field theory and the MIT bag model to describe the hadron phase and quark phase in the interior of neutron stars, respectively. Our results indicate that the onset of hadron-quark phase transition is put off and the appearance of hyperon species is increased with the increase in bag constant. As a result, the hybrid star equation of state for a mixed phase range stiffens whereas that of the quark phase range softens, and the gravitational mass as well as the corresponding radius of hybrid stars are increased obviously. The gravitational mass of a hybrid star is increased from 1.42 M （M is solar mass） to 1.63M and the corresponding radius is changed from 9.1 km to 12.2 km when the bag constant （B1/4） is increased from 170 MeV to 200 MeV. It is interesting to find that hybrid star equations of state become non-smooth when the TM2 parameter sets in the framework of relativistic mean field theory used to describe the hadronic matter, and consequently, the third family of compact stars appear in the mass-radius relations of hybrid stars in the narrow scope of the bag constant from 175 MeV to 180 MeV. These show that the choice of the bag constant in the MIT bag model has significant influence on the properties of hybrid stars.
基金National Natural Science Foundation of China (10275029, 10675054)Natural Science Foundation of Henan Education Department(2008A140009)The Science Foundation of Nanyang Normal University
文摘The properties of hybrid stars are investigated in the framework of the relativistic mean field theory （RMFT） and an MIT bag model with density-dependent bag constant to describe the hadron phase （HP） and quark phase （QP）, respectively. We find that the density-dependent B（p） decreases with baryon density p; this decrement makes the strange quark matter become more energetically favorable than ever, which makes the threshold densities of the hadron-quark phase transition lower than those of the original bag constant case. In this case, the hyperon degrees of freedom can not be considered. As a result, the equations of state of a star in the mixed phase （MP） become softer whereas those in the QP become stiffer, and the radii of the star obviously decrease. This indicates that the extended MIT bag model is more suitable to describe hybrid stars with small radii.
