Radial migration of the Sun in galactic disk
  Physics of the gravitational effect of the galactic bar and spiral structure
is presented. Physical equations differ from the conventionally used equations.
  Application to the motion of the Sun is treated. The speed of the Sun is
taken to be consistent with the Oort constants.
  Galactic radial migration of the Sun is less than +- 0.4 kpc for the
four-armed spiral structure. The Sun remains about 75 % of its existence within
galactocentric distances (7.8 - 8.2) kpc and the results are practically
independent on the spiral structure strength. Thus, the radial distance changes
only within 5 % from the value of 8 kpc.
  Galactic radial migration of the Sun is less than +- (0.3 - 1.2) kpc, for the
two-armed spiral structure. The Sun remains (29 - 95) % of its existence within
galactocentric distances (7.8 - 8.2) kpc and the results strongly depend on the
spiral structure strength and the angular speed of the spiral arms. The radial
distance changes within (3.8 - 15.0) % from the value of 8 kpc.
  If observational arguments prefer relevant radial migration of the Sun, then
the Milky Way is characterized by the two-arm spiral structure.
