We analyze a set of Type I X-ray bursts from the low mass X-ray binary 4U 1728-34 , observed with Rossi X-ray Timing Explorer ( RXTE ) .
We infer the dependence of the neutron star ( NS ) mass and radius with respect to the assumed distance to the system using an analytical model of X-ray burst spectral formation .
The model behavior clearly indicates that the burster atmosphere is helium-dominated .
Our results strongly favor the soft equation of state ( EOS ) of NS for 4U 1728-34 .
We find that distance to the source should be within 4.5-5.0 kpc range .
We obtain rather narrow constrains for the NS radius in 8.7-9.7 km range and interval 1.2-1.6 M _ { \odot } for NS mass for this particular distance range .
We uncover a temporal behavior of red-shift corrected burst flux for the radial expansion episodes and we put forth a dynamical evolution scenario for the NS–accretion disk geometry during which an expanded envelope affects the accretion disk and increases the area of the neutron star exposed to the Earth observer .
In the framework of this scenario we provide a new method for the estimation of the inclination angle which leads to the value of \sim 50 ^ { \circ } for 4U 1728-34 .