Too close, yet too far: common envelope interaction of triple systems

The common envelope interaction is a short lived phase in the evolution of binary systems. A number of evolved binary systems have been discovered that have separations too large to fit our understanding of the common envelope, and yet they are too close that a common envelope interaction must have occurred. In some of these systems, an outer tertiary companion is present, suggesting that the presence of an additional companion could have an influence on the final separation of the inner binary. We present the first hydrodynamic simulations of common envelope interactions involving triple systems. The first simulation contains a low-mass giant with two planets, the second is a 10 M RGB star with two solar-mass companions. We observe in our simulations that the outermost companion tends to move outward (or at best remains at a similar distance) from its initial position. Our findings do not support the hypothesis that a triple system could provide a pathway to leave the outer companion at an intermediate separation after a common envelope interaction.