General Astronomy - Spring
2011
Homework #3 - due February 7
1. (2 pt) List two different pairs of quantities that one could plot to
make
an HR diagram.
2. (2 pt) Which is hotter, an G9V star or an F1I star? Which is
more
luminous?
3. (6 pt) The spectral lines of two stars in a eclipsing binary shift
back and
forth with a period of 2 months. The lines of star A show shifts
indicating an orbital speed of 20,000 m/s, the lines of the star B are
half that large. What are the masses of stars A and B?
4. (6 pt) A star has an absolute bolometric magnitude of -0.3 and a
temperature of 4,300 K. What is its radius?
5. (4 pt) An A1V star has an apparent magnitude of mV = -2.4. How far
away is it?