General Astronomy -
Spring 2013
Homework #6 - due March 4
1. (2 pt) Draw a sketch of the Milky Way including the center, the
disk, the halo, and the bulge. Mark the location of the Sun
and its approximate distance from the center.
2. (2 pt) List three types of objects which are mainly found in
spiral arms.
3. (3 pt) Imagine that the orbital period of the Sun around the
center of the galaxy is found to be 1 billion years, instead of the
currently accepted 230 million years. Estimate the mass of the
Milky Way inside the orbit of the Sun using this longer orbital
period.
4. (3 pt) A Cepheid is found to have the same oscillation period,
but is 400,000 times dimmer than a Cepheid at a known distance of 1
kpc. How far away is the dimmer Cepheid?