The chemical abundances of the metal-poor stars are excellent information for setting new constraints on models of galaxy chemical evolution at low metallicity .
In this paper we present an attempt to fit the elemental abundances observed in the bright , metal-poor giant HD 175305 and derive isotopic fractions using a parametric model .
The observed abundances can be well matched by the combined contributions from s- and r-processes material .
The component coefficients of the r- and s-processes are C _ { 1 } = 3.220 and C _ { 3 } = 1.134 , respectively .
The Sm isotopic fraction in this star where the observed neutron-capture elements were produced is predicted to be f _ { 152 + 154 } = 0.582 , which suggests that even though the r-process is dominantly responsible for synthesis of the neutron-capture elements in early galaxy , the onset of the s-process has already occurred at this metallicity of [ Fe / H ] = -1.6 .