MG II Chromospheric-Emission Dating of HR 1614 Moving-Group Stars

Abstract

A 2800 A Mg II line index (Mg II) that is sensitive to chromospheric activity has been measured from International Ultraviolet Explorer spectra of a sample of eight HR 1614 moving-group dwarfs. All of these dwarfs have values of I(Mg II) indicative of ages >= 3 Gyr. The relatively old ages of these dwarfs, togther with their similar and peculiar kinematics and high chemical abundance, is consistent with, although not conclusive proof of, coeval formation in close physical proximity to each other. The age, chemical abundance, and kinematics of the HR 1614 moving group--with the notable exception of height above the Galactic plane--are similar to the properties of the old open cluster NGC 6791. (SECTION: Stars)