A PIONIER View on Mass-Transferring Red Giants
  Symbiotic stars display absorption lines of a cool red giant together with emission lines of a nebula ionized by a hotter star, indicative of an active binary star system in which mass transfer is occurring. PIONIER at the VLT has been used to combine the light of four telescopes at a time to study in unprecedented detail how mass is transferred in symbiotic stars. The results of a mini-survey of symbiotic stars with PIONIER are summarised and some tentative general results about the role of Roche lobe overflow are presented. 
Henri M.J. Boffin, Nicolas Blind, Michel Hillen, Jean-Philippe Berger,   Alain Jorissen, Jean-Baptiste Le Bouquin
astro-ph.SR astro-ph.IM