Previous works suggested that the state transitions in an X-ray binary can be triggered by accret- ing an inverse magnetic field from its companion star. A key point of this mechanism is the accretion and magnificatio...Previous works suggested that the state transitions in an X-ray binary can be triggered by accret- ing an inverse magnetic field from its companion star. A key point of this mechanism is the accretion and magnification of large-scale magnetic fields from the outer boundary of a thin disk. However, how such a process can be realized is still an open question. In this work, we check this issue in a realistic X-ray binary system. According to our calculations, a quite strong initial magnetic field, B - 10^2 - 10^3 G, is required in order to assure that the large-scale magnetic field can be effectively dragged inward and magnified with the accretion of gas. Thus, such a picture probably can be present in high-mass X-ray binaries possessing a strong stellar magnetic field, e.g., Cyg X-1.展开更多
基金supported by the National Natural Science Foundation of China (NSFC, Grant Nos. 11233006 and 11373056)the Science and Technology Commission of Shanghai Municipality (13ZR1447000)+1 种基金support from the Knowledge Innovation Program of the Chinese Academy of SciencesNSFC under grant No. 11403074
文摘Previous works suggested that the state transitions in an X-ray binary can be triggered by accret- ing an inverse magnetic field from its companion star. A key point of this mechanism is the accretion and magnification of large-scale magnetic fields from the outer boundary of a thin disk. However, how such a process can be realized is still an open question. In this work, we check this issue in a realistic X-ray binary system. According to our calculations, a quite strong initial magnetic field, B - 10^2 - 10^3 G, is required in order to assure that the large-scale magnetic field can be effectively dragged inward and magnified with the accretion of gas. Thus, such a picture probably can be present in high-mass X-ray binaries possessing a strong stellar magnetic field, e.g., Cyg X-1.
