Interferometrie stellaire : diametres et temperatures effectives de cinq geantes.

The authors report angular diameter measurements of α Ari, β Gem, β UMi, γ Dra, and δ Dra, performed from November 1980 to January 1982, using the two-telescope stellar interferometer (I2T) at the CERGA. To determine the diameter for the equivalent uniform disk, the method is inspired by that of Michelson: it is based on a visual detection of very low contrast fringes for the largest possible baseline. The diameter of α Lyr measured by I2T confirms the measurements by intensity interferometry. From 8 red giant angular diameters and from the computation of the bolometric fluxes of those stars, the authors determine effective temperatures. They obtain a good agreement with the T_eff-(V-K) relation, established from lunar occultation diameters and infrared photometry. The authors generally find diameters smaller than from indirect of theoretical methods.