Browsing by Author "Fouque, P"

Now showing 1 - 1 of 1
  • No Thumbnail Available
    Item
    An improved calibration of Cepheid visual and infrared surface brightness relations from accurate angular diameter measurements of cool giants and supergiants
    (1997) Fouque, P; Gieren, WP
    We have calibrated optical and near-infrared surface brightness - colour relations for cool giant and supergiant stars using high-precision angular diameters of these stars determined from Michelson interferometry. We find that the giant and supergiant relations are undistinguishable over a wide range of intrinsic colours. We independently determine the slopes of these relations obeyed by Cepheid variables and find that in all the diagrams considered, these agree very well with the slopes derived from the stable giants and supergiants. Forcing the slopes to the values derived from the Cepheids, we determine a very precise value of the zero point of the surface brightness - colour relations valid for Cepheid variables, which is 3.947 +/- 0.003. This value is in agreement with the one derived from the Cepheid effective temperature scale of Pel (1978), and from the lunar occultation angular diameter of the Cepheid zeta Gem (Ridgway et al. 1982).