I cannot figure out the answers for the following problems:(adsbygoogle = window.adsbygoogle || []).push({});

1) If a star has a parrallax of 0.016 second of arc and an apparent magnitude of 6, how far away is it, and what is its absolute magnitude?

7) If a star is 10 times the radius of the sun and half as hot, what will its luminosity be?

13) If the orbital velocity of the eclipsing binary in Figure 8-17 is 153 km/s and the smaller star becomes completely eclipsed in 2.5 hours, what is its diameter?

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Need homework help (Astronomy)

**Physics Forums | Science Articles, Homework Help, Discussion**