Chaos in growing bar models

Abstract

This paper aims to verify the influence of the bar, its pattern speed (Omega(b)) and its rate of growth on the stability of the orbits in gravitational potentials. We studied the nature of the orbits in potentials representing galaxies with growing bars, where a linear growth was assumed. In order to study the stability of the orbits we applied SALI. We studied six models in which the bar dimensions were fixed, but we varied their pattern speed and time of bar growth. We found that when the bar growth is faster, more chaos is generated and we also noted that the higher the Omega(b) the greater its influence on the system dynamics. The initial positions of the orbits that became chaotic were located in a well-defined ring-like region, confined between the ILR and CR resonances. There was also an indication that the retrograde orbits, although much scarcer, are more conductive to chaos when they do exist.