Life Cycle of Stars
by Lydia Pinard
Stage 1: Protostar
The Protostar is like the fetus phase of human life. This is where the stars have just formed and are brand new. Protostars form from nebulae. At this point the stars are made of hydrogen mostly (97%) and helium (3%). During the Protostar phase the star reaches Equilibrium. Equilibrium is the balance between gravity pulling atoms to its center and pressure pushing heat light away from it.
Stage 2: Main Sequence
During the main sequence the star slowly contracts in order to make up for lost heat and energy. At the same time, the star's temperature, density, and pressure increases. The temperatuer continues rising until it's core radiates away energy. After this it becomes a red giant.
Spectroscopy (What does a star's light tell us?)
Spectroscopy is the study of a star's light. It can tell us a star's temperature, chemical makeup, wavelength, and frequency (based off star's color).