1. Star Classification Pre-Activity Notes

2. A star is an enormous, hot ball of gas held together by gravity. The gravity is so strong that it causes nuclear fusion within the star. Stars are the only objects that heat & light the planets in a system.

3. A star is a huge ball of gas, usually made of hydrogen (H) & helium (He). That ball of fire also gives off all kinds of light… There are visible rays, radio waves, UV rays, infrared rays & X-rays constantly emitted into space.

4. Astronomers look at three main characteristics of stars. They study luminosity, temperature, & mass (size).