SIMBAD references

Observations of Sirius A with the GHRS instrument on board the Hubble Space Telescope revealed the presence of absorption features in the blue wings of the strong MgII and HI resonance lines in the velocity range from -20km/s to -80km/s. These features are probably due to the stellar wind of Sirius rather than to blends of photospheric lines because: 1) the absorption features in the lines of MgII h and k and in Lyman-α are at the same velocity, 2) the two features of the MgII lines have about the same asymmetric shape, 3) the depths of the two MgII h and k features have a ratio of about 1/2 which is the doublet ratio, 4) the blue wing of the h and k features agrees approximately with the expected variation of the optical depth of a line formed in a wind of low mass loss rate. A similar feature seems to be present in the CII resonance lines. The mass loss rate derived from the MgII lines is between 2x10^–13 and 1.5x10^–12M_☉/yr depending on the assumed ionization fraction of MgII. This mass loss rate is a factor 10^–2 smaller than the upper limit derived from the Hα line. The mass loss rate agrees with the requirements for interpreting the chemically peculiar A stars by means of diffusion and mass loss. The mass loss rate of Sirius predicted by the radiation driven wind theory is 1.0x10^–12M_☉/yr with an uncertainty of a factor 3, and the predicted terminal velocity of the wind is v_∞≃1300km/s. The approximate agreement between the observed and predicted mass loss rate suggests that the wind of Sirius A might be radiation driven.