Dynamics of the spiral-arm corotation and its observable footprints in
  the Solar Neighborhood
  This article discusses the effects of the spiral-arm corotation on the
stellar dynamics in the Solar Neighborhood (SN). All our results presented here
rely on: 1) observational evidence that the Sun lies near the corotation
circle, where stars rotate with the same angular velocity as the spiral-arm
pattern; the corotation circle establishes domains of the corotation resonance
(CR) in the Galactic disk; 2) dynamical constraints that put the spiral-arm
potential as the dominant perturbation in the SN, comparing with the effects of
the central bar in the SN; 3) a long-lived nature of the spiral structure,
promoting a state of dynamical relaxing and phase-mixing of the stellar orbits
in response to the spiral perturbation. With an analytical model for the
Galactic potential, composed of an axisymmetric background deduced from the
observed rotation curve, and perturbed by a four-armed spiral pattern,
numerical simulations of stellar orbits are performed to delineate the domains
of regular and chaotic motions shaped by the resonances. Such studies show that
stars can be trapped inside the stable zones of the spiral CR, and this orbital
trapping mechanism could explain the dynamical origin of the Local arm of the
Milky Way (MW). The spiral CR and the near high-order epicyclic resonances
influence the velocity distribution in the SN, creating the observable
structures such as moving groups and their radially extended counterpart known
as diagonal ridges. The Sun and most of the SN stars evolve inside a stable
zone of the spiral CR, never crossing the main spiral-arm structure, but
oscillating in the region between the Sagittarius-Carina and Perseus arms. This
orbital behavior of the Sun brings insights to our understanding of questions
concerning the solar system evolution, the Earth environment changes, and the
preservation of life on Earth.
