DG Leo: A triple system with a surprising variety of physical phenomena

Abstract

DG Leo consists of three late A-type stars forming a hierarchic and spectroscopic triple system. Although all components have similar age and mass, in-depth spectroscopic analysis showed that the components nevertheless behave differently with respect to pulsation and to diffusion in their outer atmospheres. Inclusion of a speckle measure shortly after periastron passage allows to obtain a much improved orbital solution as well as a reliable dynamical parallax and systemic mass. The orbital parameters also suggest a possible coplanar configuration of both pairs. This object therefore represents a first-class opportunity to investigate the link between multiplicity, chemical composition and pulsation in a coeval system. © 2008 Springer-Verlag Berlin Heidelberg.