Clusters and Associations

 

Open Star Clusters:

          100 to 1000 members;

          4 to 20 pc in diameter;

          Concentrated along the plane of our galaxy.

 

Associations:

          10 to a few hundred members;

          10 to 100 pc in diameter;

          Concentrated along the plane of our galaxy.

 

Globular Star Classes:

          20,000 to several million stars;

          5 to 25 pc in diameter;

          distributed in a spherical halo surrounding our galaxy.