Periodic changes in the orientation of orbits and the age of the Galactic bar

We studied the model of the Galaxy that reproduces the observed median velocity distribution derived from Gaia DR3 data along the Galactocentric distance, $R$. The model profiles of radial velocity, $V_R$, demonstrate an increase with a period of $P = 2.1 \pm{0.1}$ Gyr and form humps at $R = $ 6-7 kpc. The average amplitude of variation in the radial velocity is $A = 1.76 \pm{0.20}\, \rm km\, s^{-1}$. The humps are supported by orbits changing orientation relative to the major axis of the bar within the range of $[-45, \;45]$$^{\circ}$. The median period of variation in the angular momentum of hump-supporting orbits is $P = 1.85 \pm{0.17}$ Gyr, and 71.6 % of them support ring $R_2$. The observed profile does not show any humps. In the model profile, humps disappear during the times $2.5 \pm{0.3}$ and $4.5 \pm{0.5}$ Gyr, indicating that the age of the Galactic bar must be close to one of these values. The model disk forms outer resonance rings $R_1$ and $R_2$, which demonstrate periodic changes in their morphology with a period of $P = 2.0\pm{0.1}$ Gyr, supported by orbits trapped by the Outer Lindblad Resonance.