Détermination des rayons de Céphéides ^*,**

V. Vitesses radiales et dimensions de 22 Céphéides galactiques Determination of the radii of Cepheids V. Radial velocities and dimensions of 22 galactic Cepheids

Observatoire de Marseille, 2 place Le Verrier, F-13248 Marseille Cedex 04, France

Send offprint request to: M. Imbert

Received: 7 April 1999
Accepted: 9 September 1999

Abstract

We present radial velocity data for 22 galactic Cepheid stars obtained with Coravel spectrometer. Continuous observation over several years has enabled us to obtain 852 individual velocities covering all the phases of the pulsation. The mean number of measurements per star is 39, ranging from 20 to 113. For each star radial velocity versus phase diagrams have been fitted by analytical relation, and the stellar radius variation has been derived by integration of this relation over the whole period. Using recent ubv photometry of the literature and velocity curves, we have calculated the radii of the stars using a method based on the Baade-Wesselink concept. For these 22 Cepheids we give a linear logarithmic period-radius relation with a range of 2,4 to 45 days.