Capture of free-oating planets by stellar systems

  Nadav Gulinski  ,  Erez Ribak  

Evidence of exoplanets with orbit that are misaligned with the spin of the host star may suggest that not all bound planets are born in the protoplanetary disk of their current planetary system. Observations have showed that Jupiter-mass objects that may be considered as free floating planets candidates can exceed the number of stars in our galaxy, implying that capture scenarios may not be so rare. To address this issue, we construct a three dimensional three-body simulation where a free floating planet encounters a binary system of a Jupiter-mass planet moving on a circular orbit around a Sun-like star. Different initial condition may lead to different outcomes of the simulation where the free floating planet may be captured by the system, continue as an unbound object, or even “kick out” the bound planet and take it's place instead. The outcome statistics are used to construct a cross-section for capturing a free floating planet which in-turn is used to predict the capture-rate for these kind of objects.