The determination of physical parameters such as effective temperature, surface gravity, luminosity, and radius of a star requires an adequate analysis of its spectroscopic readings. In this paper, the main aim is to determine the physical parameters of the star HD149382 from its spectrum. Our indirect method consists in determining the half-height width of the profiles of the He I λ471.362 nm, He I λ501.605 nm, et He I λ667.872 nm lines which have a bell-shaped profile and which result from the radiative life within the star and the lifetime of the particles after collisions. We use a Gaussian curve for helium line modeling. This
modeling consists first in extracting the considered lines and modeling them from the Matlab software. Our method is mainly based on the determination of the effective temperature, the radius, the surface gravity and the luminosity of the
star HD149382 by Doppler Effect thanks to the half-height width of the Gaussian profile of the modeled absorption line. The results obtained show that the effective temperature, the surface gravity, the luminosity, and the radius have values ranging respectively between 33 427-40 051.7 K, 4.979-6.764 cm.s-2,
86.821-86.675 erg/K3/s et 3.34 Rʘ -10 Rʘ and that the star HD149382 is a dwarf
star of sdB type.

HD149382 ; Indirect method ; Physical parameters