Orbit evolution in growing stellar bars: bar-supporting orbits at the vertical ILR region

ABSTRACT We investigate the evolution of orbital shapes at inner Lindblad resonance region a rotating 3D bar, mass which is growing with time. evaluate in time-dependent models, during 5 Gyr period, importance orbits initial conditions known to play significant role supporting peanut-like structures autonomous systems. These are central family periodic (x1) and vertical perturbations it, its standard bifurcations (x1v1 x1v2), as well their neighbourhood. The knowledge regular or chaotic character these essential well, because it allows us estimate contribution support bar and, more importantly, dynamical mechanisms that make possible. This calculated by means GALI2 index. find patterns existing case, persist for longer times massive even so model spheroid component our adopted galactic potential becomes rather insignificant. peanut-supporting we find, have or, most cases, weakly character. There cases starting close unstable an behave when increases As rule thumb dynamics non-autonomous models certain time, can be considered corresponding frozen systems around