Tabla de Contenidos

GLOBULAR CLUSTERS



What do you need?


  1. Paper and pen.
  2. You must know about:



Statement



Take a globular cluster of the following ones and take a random radius in the mentioned cluster.
For this chosen radius, what's the number of stars that forms the globular cluster?



      GLOBULAR CLUSTER OF HÉRCULES (M13)

average density = 1 solar mass / light year cubic

      GLOBULAR CLUSTER M80

average density = 0.22 solar mass / light year cubic

      GLOBULAR CLUSTER 47-TUCANAE

average density = 0.7 solar mass / light year cubic

How can we solve it?


What do we know?

In this exercise we know of every globular cluster: average density and the radius ( we can know it using the salsaJ program).

What do we have to find out?

We need know the number of star that compose a globular cluster, knowing that this number won't be the same, becouse it depends on the chosen radius.



How do we calculate it?
  1. We take a random radius whit the help of the salsaJ program.
  2. For this radius, we must calculate the volume of the globular cluster.
  3. We have got the average density as a information.
  4. To obtein the total mass, we use the formule of the density of a body.
  5. The mass of the stars which are placed in our globular clusters is liked as mass of sun, therefore, so we can obtein the number of stars to the marked radius.