The stability of accreting triples

We address the question of the stability of newly formed stellar triple systems that are undergoing accretion, Accretion of infalling gas can help stabilize unstable triple systems and can destabilize stable ones. The dynamics of the accretion depend critically on the specific angular momentum of the infalling gas relative to that of the triple system and on the component masses. Low relative specific angular momentum accretion helps to stabilize systems where a lower mass single star is orbiting a more massive binary, by preferentially shrinking the separation of the binary over that of the binary-single. High relative specific angular momentum accretion also helps to stabilize these systems, but by increasing the binary-single separation. Moderate values of the relative specific angular momentum of the infalling matter can destabilize previously stable systems, Systems with comparable-mass single components are stabilized by accreting matter with significant angular momentum, while they can be destabilized by accreting zero angular momentum material. Triples composed of a binary orbiting a more massive star are easily destabilized for most values of the specific angular momentum of the infalling gas. Such systems are unlikely to survive significant accretion, We comment on how these scenarios can arise depending on the triple formation mechanism, and discuss the implications that accretion has for stellar multiplicity.