Neutron star mass-radius relation with gravitational field shielding by a scalar field  

作　　者：Bo-Jun Zhang Tian-Xi Zhang Padmaja Guggilla Mostafa Dokhanian 

机构地区：[1]Department of Physics and Astronomy, Vanderbilt University [2]Department of Physics, Alabama A & M University [3]National Astronomical Observatories, Chinese Academy of Sciences

出　　处：《Research in Astronomy and Astrophysics》2013年第5期571-578,共8页天文和天体物理学研究（英文版）

基　　金：supported by NASA EPSCoR(NNX07AL52A);NSF CISMand REU,the Alabama A&M University(AAMU)Title Ⅲ programs;the National Natural Science Foundation of China(Grant No.40890161)

摘　　要：The currently well-developed models for equations of state （EoSs） have been severely impacted by recent measurements of neutron stars with a small radius and/or large mass. To explain these measurements, the theory of gravitational field shielding by a scalar field is applied. This theory was recently developed in accor- dance with the five-dimensional （5D） fully covariant Kaluza-Klein （KK） theory that has successfully unified Einstein＇s general relativity and Maxwell＇s electromagnetic theory. It is shown that a massive, compact neutron star can generate a strong scalar field, which can significantly shield or reduce its gravitational field, thus making it more massive and more compact. The mass-radius relation developed under this type of modified gravity can be consistent with these recent measurements of neutron stars. In addition, the effect of gravitational field shielding helps explain why the supernova explosions of some very massive stars （e.g.9 40 MQ as measured recently） actually formed neutron stars rather than black holes as expected. The EoS models, ruled out by measurements of small radius and/or large mass neutron stars according to the the- ory of general relativity, can still work well in terms of the 5D fully covariant KK theory with a scalar field.The currently well-developed models for equations of state （EoSs） have been severely impacted by recent measurements of neutron stars with a small radius and/or large mass. To explain these measurements, the theory of gravitational field shielding by a scalar field is applied. This theory was recently developed in accor- dance with the five-dimensional （5D） fully covariant Kaluza-Klein （KK） theory that has successfully unified Einstein＇s general relativity and Maxwell＇s electromagnetic theory. It is shown that a massive, compact neutron star can generate a strong scalar field, which can significantly shield or reduce its gravitational field, thus making it more massive and more compact. The mass-radius relation developed under this type of modified gravity can be consistent with these recent measurements of neutron stars. In addition, the effect of gravitational field shielding helps explain why the supernova explosions of some very massive stars （e.g.9 40 MQ as measured recently） actually formed neutron stars rather than black holes as expected. The EoS models, ruled out by measurements of small radius and/or large mass neutron stars according to the the- ory of general relativity, can still work well in terms of the 5D fully covariant KK theory with a scalar field.

关 键 词：stars： neutron -- gravitation -- black hole physics -- equation of state 

分 类 号：P145.6[天文地球—天体物理]