中国科学院新疆天文台机构知识库

Using data from the Rossi X-Ray Timing Explorer, we investigate the spectral evolution along a "Z" track and a "v" track on the hardness-intensity diagrams of the first transient Z source XTE J1701-462. The spectral analyses suggest that the inner disk radius depends on the mass accretion rate, in agreement with the model prediction, R-in alpha (M) over dot(disk)(2/7), for a radiation-pressure-dominated accretion disk interacting with the magnetosphere of a neutron star (NS). The changes in the disk mass accretion rate (M) over dot(disk) are responsible for the evolution of the "Z" or "v" track. Radiation pressure thickens the disk considerably and also produces significant outflows. The NS surface magnetic field strength, derived from the interaction between the magnetosphere and the radiation-pressure-dominated accretion disk, is similar to(1-3) x 10(9) G, which is possibly between normal atoll and Z sources. A significant hard tail is detected in the horizontal branches and we discuss several possible origins of the hard tail.