AST 307, Fall 2003

Homework #6, Due Wednesday, December 3

1. Calculate the number of "peices" expected in the Milky Way halo given a total stellar mass of 10^9 solar masses, and adopting a mass distribution of the consitutuents of N(M) is proportional to M^-2. Note that the upper limit of a possible "peice" is the total mass, and for a lower limit, adopt 10^5 solar masses, since objects less massive than this tend to have their gas always photoionized by diffuse intergalactic radiation. If you want, you can try different lower mass limits.

2. (a) If the density of stars is 0.05 pc^-3, and assuming the Sun is a typical star, what fraction of the volume is occupied by stars?
(b) If a star passes through a disk 1 kpc thick of stars of this density, what is the probability it will collide with one of them?
The idea of this problem is to make clear how rare stellar collisions are.


Old Homework - #1

Old Homework - #2

Old Homework - #3

Old Homework - #4