Collisions in young triple systems

TL;DR

This study uses N-body simulations to analyze collision probabilities in young triple star systems, revealing that coplanar and closely separated companions have a significant chance of collision, which may explain some observed anomalies.

Contribution

The paper provides new insights into collision likelihoods in young triple systems under various initial conditions through detailed N-body simulations.

Findings

20% collision chance for coplanar, closely separated companions

Few percent collision probability with realistic, slightly non-coplanar initial conditions

Rare collisions when companions are widely separated unless total mass is large

Abstract

We perform N-body simulations of young triple systems consisting of two low-mass companions orbiting around a significantly more massive primary. We find that, when the orbits of the companions are coplanar and not too widely separated, the chance of a collision between the two companions can be as high as 20 per cent. Collisions between one of the companions (always the less massive) and the primary can also occur in systems with unequal-mass companions. The chance of collisions is a few per cent in systems with more realistic initial conditions, such as with slightly non-coplanar orbits and unequal-mass companions. If the companions start widely separated then collision are very rare except in some cases when the total mass of the companions is large. We suggest that collisions between members of young multiple systems may explain some unusual young multiple systems such as apparently non-coeval companions.