Effects of rotation on the colours and line indices of stars. V - The ZRMS and the ZRZAMS

Abstract

The observed uvby and H-beta indices of member stars of the Hyades and Praesepe clusters are analyzed in detail for rotation. The slopes of the rotation effects observed are utilized to determine the zero rotation main sequence (ZRMS) values of the intermediate band photometric indices for selected clusters. A preliminary calibration of the absolute visual magnitudes as a function of beta valid for zero rotation zero age main sequence (ZRZAMS) is derived