Rotational velocities for 112 members of the Scorpio-Centaurus association brighter than 8.5 magnitudes are derived from spectra obtained with a dispersion of 47 A/mm. Hydrogen and helium line intensities are determined ...

The extinction efficiencies for small smooth metallic particles (granules) have been calculated using rigorous Mie theory of scattering. Strong size-dependent resonances for spheres composed of sodium, potassium, and calcium ...