Kinematical model for stellar subsystems.
Abstract
A kinematical model for galactic stellar systems is developed taking into account all the possible orbits of any eccentricity passing through a given point interior to the region defined by the stellar group in study. This treatment yields the prediction of radial velocities observed from the sun as a function of galactic longitude. A family of curves is generated with eccentricities and distances as parameters. It is found that the theoretical curves enclose the observed radial velocities of planetary nebulae. Maximum and minimum values of radial velocities describe quite well the contour of the permitted area of radial velocities of objects moving in noncircular orbits. The description of the kinematics of planetary nebulae using the present model seems to be more complete as compared with models based only on circular orbits, which cannot describe all the features of the observed velocity dispersion.
 Publication:

Astronomy and Astrophysics
 Pub Date:
 January 1977
 Bibcode:
 1977A&A....54...79P
 Keywords:

 Galactic Structure;
 Kinematics;
 Planetary Nebulae;
 Radial Velocity;
 Stellar Models;
 Stellar Systems;
 Boundary Value Problems;
 Circular Orbits;
 Eccentric Orbits;
 Longitude;
 Orbit Calculation;
 Astrophysics