Virial Theorem for an expanding Star Cluster

[Barbequeman]

Good morning

I have a certain problem to find the answer to a problem with a question for my "homework" it contains the virial theorem for an unrotating and in the equilibrium state star cluster which is not contracting, instead it is expanding. therefore we need to calculate the kinetic energy of the stars in this system and the total energy of this system. I know we need to use the simplest form of the virial theorem 2K+U=0 because it is unrotating and in equilibrium.

We now have the radius of a sphere of finite radius and density r_c, the mass of the gas which is M_g which is given by M_g = f*M_star where M_star is the total mass of the stars in the cluster. My problem is now to plug it into make sense out of it ... I resolved everything in our course notes but there it seems I´m pretty much stuck ... We are therefore looking for the kinetic energy of the system in terms of r_c, f and M_star and the total energy of the system.

It would be very nice to get some help in this case ... because I cannot see the answer.

Best wishes

BBQman

 

[berkeman]

Good morning

I have a certain problem to find the answer to a problem with a question for my "homework" it contains the virial theorem for an unrotating and in the equilibrium state star cluster which is not contracting, instead it is expanding. therefore we need to calculate the kinetic energy of the stars in this system and the total energy of this system. I know we need to use the simplest form of the virial theorem 2K+U=0 because it is unrotating and in equilibrium.

We now have the radius of a sphere of finite radius and density r_c, the mass of the gas which is M_g which is given by M_g = f*M_star where M_star is the total mass of the stars in the cluster. My problem is now to plug it into make sense out of it ... I resolved everything in our course notes but there it seems I´m pretty much stuck ... We are therefore looking for the kinetic energy of the system in terms of r_c, f and M_star and the total energy of the system.

It would be very nice to get some help in this case ... because I cannot see the answer.

Best wishes

BBQman

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