D O C . 5 6 G L O B U L A R S T A R C L U S T E R S 2 3 3
of the star cluster under long exposure and also from the distribution of fixed stars
in our neighborhood, one can estimate that the number of fixed stars that contribute
to the gravitational field of the cluster is about 100 times larger than we have as-
sumed above. In this manner we obtain a radius of the star cluster of 65 light years,
a value that is not so far off the lower limit that has been estimated in a different
way.
The incompleteness of the material presently available from observations forces
us for the time being to be content with this agreement in the order of magnitude.
More precise results have to be based upon a better knowledge of star masses and
star velocities. But one conclusion of considerable interest can be drawn from the
agreement in the order of magnitude, and that is that the nonluminous masses con-
tribute no higher order of magnitude to the total mass than the luminous masses.