1. How far away is Betelgeuse from Earth with a parallax of 0.005 arcseconds? (givens, equation, solve with units) 6. How far away is Rigel from Earth with a parallax of 0.0038 arcseconds? (givens, equation, solve with units)

9. Proxima Centauri is 4 x 10^16 m from Earth and has an apparent brightness of 3.2 x 10^-11 W/m^2. What is its luminosity? (givens, equations, solve with units)

10. What is the luminosity of Spica that is 2.5 x 10^18 m from Earth and has an apparent brightness of 6 x 10^-8 W/m^2? (givens, equation, solve with units)

14. Regulus on average is 10,300 K with a luminosity of 1.1 x 10^29 W. What is its radius? (givens, equation, solve with units)

15. Castor has an average surface temperature of 3820 K and a luminosity of 2.8 x 10^25 W. What is its radius? (givens, equation, solve with units)