The mass of a star can be determined..
•binary star systems
2. A light-year is approximately...
•9.5 trillion kilometers
3. The difference in the brightness...
•sizes
4. A Hertzsprung-Russel diagram..
• temperature and absolute magnitude
5. Which main-sequence stars are...
•blue
6. the outermost layer of the sun is called...
•corona
7. the suns surface is made up mostly of...
•hydrogen
8. Sunspots appear dark because they are...
•relatively cool
Hope it helps. :)