Line profiles and a model of the envelope of the type 2 supernova SN 1970 g

Profiles of the Hsub(α) and Na I lambda 5892 lines observed in the spectrum of SN 1970g were calculated. From a comparison of the calculated and observed profiles, the expansion velocity Vsub(c) at the photosphere level was found. Vsub(c) turned out to be significantly smaller than the radial velocity of absorption minima. The value of Vsub(c) decreases with time. The kinematic radius of the photosphere gets its maximum value practically simultaneously with photometric radius approximately on the tenth day after the end of the ''plateau'' phase. From the Hsub(α) profile, the value of electron density nsub(e) was determined independently of the distance. According to estimates, the ionized hydrogen mass in the envelope is 0,1-0,2 M*, where M* is the solar mass. The distribution of the ionized hydrogen concentration versus velocity in the envelope of SN 1970g on the 92nd day has a maximum near 1400 km/s. The gas density in the envelope decreases with the velocity at least in the range V > 1500 km/s