DG Leo, a triple system with a surprising variety of physical phenomena

P. Lampens, Royal Observatory, Brussels (Belgium)
V. Tamazian and J. Docobo (Observatorio Astronomico Ramon
Maria Aller, Santiago de Compostela, Spain), Y. Fremat
(Observatoire royal de Belgique, Belgium) and Y. Balega (Russia)

DG Leo consists of three late A-type stars forming a hierarchical and 
spectroscopic triple system. The wide binary AB was also visually 
monitored by means of micrometric observations since 1935 and by 
speckle-interferometry since 1976. A full set of orbital parameters
was first obtained by Fr\'emat et al. (2005). Although all three
components
have similar age and mass, in-depth spectroscopic analysis showed
that the components nevertheless behave differently with respect to
pulsation and diffusion in their outer atmospheres.
This object thus offers a first-class opportunity to investigate the
link between chemical composition, multiplicity and pulsation in a
system with a unique formation history.
We will present an improved orbital solution and derive a more 
accurate total mass for this astrophysically very rewarding system.