Calcium Emission Intensities as Indicators of Stellar Age

Abstract

Fresh data are presented concerning the calcium emission intensities of 325 main-sequence late-type stars estimated by one of the authors (0. W.). These are compared with parameters of the galactic orbits of the stars according to methods worked out at R.G.O. A very clear correlation is found between the calcium emission intensities and the eccentricities and box angles (inclinations) of the orbits. This reinforces the view that main-sequence stars with strong calcium reversals are young stars, and have near circular orbits with low inclinations to the galactic plane; while stars with feeble emissions are old stars which have, statistically, high eccentricities and high inclinations to the galactic plane.