Scanner observations of the classical cepheids RT Aur and T Vul

The effective temperatures of the classical Cepheids RT Aur and T Vul have been determined by a comparison of their spectral scans with appropriate model atmospheres. The radii of the stars have been determined through the Wesselink method. Using these temperatures and the Wesselink radii, the luminosities of the stars have been determined. These radii estimates, including the radii of SU Cas (Joshi & Rautela 1980) andζ Gem (unpublished) fit better in the theoretical period-radius relationship given by Cogan (1978), as compared to earlier determinations of Wesselink radii. The pulsation masses and evolutionary masses of the stars have been calculated. The pulsation to evolutionary mass ratio is derived to be 0.85. Based on the effective temperatures obtained by us at different phases of the stars aθ _c ? (B-V)₀ relationship is found of the form, (begin{gathered} theta _e = 0.274 (B - V)_0 + 0.637 pm 0.011 pm 0.007 end{gathered} )