| dc.description | The study of the series of spectra of Gamma-2 Velorum taken by C. D. Perrine at the Córdoba Observatory in 1919 suggests that the variations in the radial velocities and in the intensities of the absorption lines that show the effect of diluted radiation are periodic with Vainu Bappu and Ganesh’s period of 78,5 days and permits to improve this figure to 78,5002 days. The same period is followed by V/R variations displayed by the emissions of H and He I. Thus the emission features of Gamma-2 Velorum can be separated into two groups, one of the broad H and He I emissions that show V/R variations, and a second one of the relatively narrow and stronger He II, C IV, O IV, etc. lines that do not show V/R variations. One obvious conclusion is that the Wolf - Rayet spectrum does actually show H in its spectrum, the behaviour of the H lines being different than the behaviour of He II. The examination of the spectra taken at Bosque Alegre by Sahade in the interval 1948-62 and that of the spectra taken by Perrine, suggest that no noticeable changes have occurred in the spectrum of Gamma-2 Velorum in the last fifty years. Furthermore, the V/R variations in the red part of the spectrum is also shown on the 1948-62 plates. Identifications of the spectral features are given in the wavelength range λ 3100 - 6800 A. Relative to H8, the distribution of the radial velocities of the absorption line of He I 3888 that show dilution effect and is violet displaced by about 1200 km /sec on the average, both on Perrine’s plates as well as on those taken with the Bosque Alegre reflector, apparently follow the trend of the radial velocities of the W - R component but with a much larger amplitude. This will be checked with the measurement of the Bosque Alegre spectra and may be explained in terms of form and density distribution of the envelope that surrounds the whole system.
The paper will be published in full elsewhere. | |
