ABSTRACT
Spectrograms of GG Car were made at the Bosque Alegre Astrophysical Station of the Cordoba Observatory, Argentina in 1950 and 1951 with a dispersion of 42 A/mm; at the Radcliffe Observatory, South Africa in 1953-56 with dispersions of 29.6 A and 49.3 A/mm at H-gamma, and at the Cerro Tololo Inter-American Observatory, Chile in 1968-70, 1976 and 1979. Radial velocities of the P Cygni H absorptions were plotted, distribution versus time, and a 31-day period was established for the binary system. The component that is behind at eclipse is surrounded by an expanding, thick, extended envelope that does not permit observation of the lines arising in the stellar photosphere. The thick envelope is expanding with a velocity of 140 km/sec, with forbidden Fe II forming in a lower density level. It is speculated that the weak H emission originates from an envelope that surrounds the whole system.