Effective temperatures, and radii of luminous O and B stars : a test for the accuracy of the model atmospheres.

Integrated total flux and the IR flux are used by the method of Blackwell and Shallis (1977) to derive effective temperatures and angular diameters for 37 early-type stars which range in spectral type from O8 to B2, cover the luminosity classes Ia-V, and include Zeta Pup (O4 If). It is found that: (1) the observed flux distribution for supergiants does not agree with line-blanketed model atmosphere predictions; (2) the observed flux at wavelengths lower than 2000 A is smaller than predicted; and (3) the Balmer jump is smaller than predicted. The temperatures derived, to an accuracy of 1000-1500 K, are 1500 K smaller than those derived in an analogous way by Underhill et al (1979), and angular diameters are found to be in agreement with those from interferometric data.