sentences:  Division on Dynamical Astronomy
  
  The Division on Dynamical Astronomy (DDA) is a branch of the American Astronomical Society that focuses on the advancement of all aspects of dynamical astronomy, including celestial mechanics, solar system dynamics, stellar dynamics, as well as the dynamics of the interstellar medium and galactic dynamics, and coordination of such research with other branches of science.It awards the Brouwer Award every year, which was established to recognize outstanding contributions to the field of Dynamical Astronomy, including celestial mechanics, astrometry, geophysics, stellar systems, galactic and extra galactic dynamics.