Investigating the flyby scenario for theHD141569 system

摘要

The debris dust disk around HD 141569 assumes a complex structure, with gaps, asym-metric features and a spiral structure. At least part of these features, are supposed to be due to thegravitational influence of the two M2-M4 stellar companions of the primary star. Recent observa-tions have been able to re-measure the radal velocities of the components of this system. The twolow mass companions are unbound to the system. Using radial velocity and proper motion con-straints we are able to contrain the fly-by orbit. Using symplectic integration tools, we simulate thegravitational perturbation of the passing stars on the dust disk. The flyby scenario reproduces mostof the observed features in the disk. However, not all structures are explained by this model. We thenadd a hidden planet in the disk to the simulations. With this planet + flyby model, the present shapeof the disk can be much better reproduced this way. We also derive constraints on the characteristicsof the suspected planet. Subsequently, we discuss the implications of this scenario. It turns out thatthe three stars probably formed formerly a bound system, on a more distant orbit. A passing starthen perturbed the companions at apoastron, thus making them unbound to the primary.