%A Ren Ji-Rong(任继荣) and Guo Heng(郭恒) %T Topological aspects in a two-component Bose condensed system in neutron star %0 Journal Article %D 2009 %J Chin. Phys. B %R 10.1088/1674-1056/18/8/043 %P 3379-3383 %V 18 %N 8 %U {https://cpb.iphy.ac.cn/CN/abstract/article_110917.shtml} %8 2009-08-20 %X By making use of Duan--Ge's decomposition theory of gauge potential and the topological current theory proposed by Prof. Duan Yi-Shi, we study a two-component superfluid Bose condensed system, which is supposed to be realized in the interior of neutron stars in the form of the coexistence of a neutron superfluid and a protonic superconductor. We propose that this system possesses vortex lines. The topological charges of the vortex lines are characterized by the Hopf indices and the Brower degrees of $\phi$-mapping.