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ASTR 5610, Majewski [SPRING 2016]. Lecture Notes

ASTR 5610 (Majewski) Lecture Notes


Equilibrium Shape of a Globular Cluster

Luminosity/Mass Functions and Luminosity/Mass Segregation

Historically difficult to derive for clusters because of crowding problems for dense clusters.

There is no reason to believe that there is a universal luminosity function for globular clusters.

Note that King models of clusters that include multiple mass components (not surprisingly) fit typical globular clusters better.

From Binney & Merrifield Figure 6.18.
These models assume that equipartition of energy should take place, and that, therefore, lower mass stars should be less centrally concentrated than high mass stars.

Later Evolution of a Globular Cluster

The later evolution of a cluster involves several processes that results in a changing equilibrium state: