Abstract:

The influences of hyperon coupling constant on the properties of neutron star were studied by making use of GL85 parameter set in the framework of the relativistic mean field theory (RMFT) and taking freedoms of hyperons into consideration. Numerical results indicate that with the increase of the hyperon coupling constant, the onset density of hyperon Σ-  increases and those of other hyperons （Λ,Σ⁺,Σ ⁰,Σ^-,Ξ⁰,Ξ^-） decrease, the equations of state soften, the maximum mass of the star increases and the corresponding radius decreases. The maximum mass of the star increases from 1.36M_⊙ （M_⊙=1.99×10³⁰ kg is the solar mass） to 1.97M_⊙ and corresponding radius changes from 12.1 km to 11.3 km with the increase of the coupling constant from 0.4 to 1.0. We also found out the minimum coupling constant for this parameter set  corresponding to lower limit of neutron star mass （1.4M_⊙）.

Key words: relativistic mean field theory; , hyperon coupling constant; , equations of state; , mass\, radius relations