Modelling the emission and/or absorption features in the high resolution spectra of the southern binary system: HH Car

High-resolution spectra (R=48000) of the close binary system, HH Car, has been analyzed with modern analysis techniques. Precise absolute parameters were derived from the simultaneous solution of the radial velocity, produced in this study and the light curves, published. According to the results of these analyses, the primary component is an O9 type main sequence star with an effective temperature of 33500 ˚K while the secondary component is a giant/subgiant star with a spectral type of B0 and an effective temperature of 27500 ˚K. The distance and the center of mass velocity of the system were determined from the light curves and the spectra as d=3.0 kpc and Vg=-16 km/s, respectively. These calculated values of d and Vg are in good agreement with those of Car OB1 association. H-alpha emissions can be seen explicitly in the spectra of HH Car. These features were modelled using the SHELLSPEC code which requires the absolute parameters of the components for modelling. Since components of HH Car are massive early-type stars, mass loss through stellar winds can be expected. This study revealed that the components of HH Car have stellar winds and the secondary component loses mass to the primary. Stellar winds and the gas stream between the components were modelled as a hot shell around the system, with a temperature of ~22000 ˚K. Also, it is determined that the interaction between the winds and the gas stream leads to formation of a high-temperature (100000 ˚K) impact region.