All Tables

Table 1: Characteristics of the O star sample. The spectral type is taken from Mason et al. (1998), except where indicated. The "observed'' absolute magnitude $M_V^{\rm H}$ is calculated from the Hipparcos parallax $\pi _{\rm H}$ (in mas), and is corrected for interstellar extinction ( $A_{\rm V}$ ). The predicted absolute magnitude $M_V^{\rm SK}$ is derived from the spectral type according to the calibration of Schmidt-Kaler et al. (1982).
Table 2: Characteristics of the B stars in the sample of Lamers et al. (1997) depicted in Fig. 5. The "observed'' absolute magnitude $M_V^{\rm H}$ is calculated from the Hipparcos parallax $\pi _{\rm H}$ (in mas), and is corrected for interstellar extinction and the presence of spectroscopic companions. The predicted absolute magnitude $M_V^{\rm SK}$ is derived from the spectral type according to the calibration of Schmidt-Kaler et al. (1982), if necessary through interpolation (note that they have a special section for Be stars). $v \sin i$ is in km s^-1.