Extra Problems - Stars

1. A star has a parallax of 0.015 arc seconds. What is its distance in parsecs?
2. A star radiates most strongly at 150 nm. Use Wien's Law to find its surface temperature.
3. A binary star pair has an orbital period of 6 years. The stars are separated by 4 AU. What is their combined mass in Solar units?
4. A star has a surface temperature of 24,000 K and a luminosity 10,000 times that of the Sun. What is the star's radius in solar units?
5. Calculate the average density of a red giant star given that its mass is 2 solar masses and that its radius is 50 times that of the Sun. Take the Sun's mass to be 2x10³³ grams and its radius to be 7x10¹⁰ cm.
6. Two stars in orbit around each other complete their revolution in 20 years. They are 10 AU apart. What is their combined mass in solar units?