The reality of old moving groups - the case of HR 1614. Age, metallicity, and a new extended sample

Abstract

We prove the existence of the old and metal-rich moving group HR 1614. This is done using the new Hipparcos parallaxes in combination with metallicities derived from Strömgren photometry, supported by dynamical simulations of the evolution of old moving groups in the galactic potential. A new selection criterion for this moving group is presented as well as a new, extended sample of probable member stars. In particular we find that the HR 1614 moving group has an age of about 2 Gyr (using Bertelli et al. 1994 isochrones) and a [Fe/H] =~ 0.19 +/- 0.06 dex. We also revisit and apply our new selection criterion to the samples in Eggen (1992) and Eggen (1998b). It is found that, when binaries and stars with too low metallicity have been removed, 15 of his stars fulfill our criteria. Based on observations with the ESA Hipparcos satellite.