AST201H1 Lecture Notes - Lecture 9: Orion Nebula, Star Formation, Hydrostatic Equilibrium

• School: UTSG
• Department: Astronomy & Astrophysics
• Course: AST201H1
• Professor: Michael Reid

Document Summary

Since blue stars don"t live very long (red live very long), you would expect to see more blue stars where a new stars are being made. Galaxies that have more blue light have more young stars. Red nebulae is hydrogen gas (hydrogen emits red wavelengths of light) lots of blue stars -> lots of young stars lots of dust among the stars. Visible light shows hot gas and stars. The infrared light shows all the cold dust. Dust absorbs visible light, heats up, and re-emits that light in the infrared. In such nebulae, we tend to find lots of dark patches -> gas and dust concentrated enough to block out background light. These are places where new stars form. Nebulae are rich in molecules -> molecular clouds. We can use infrared light to measure how much light it blocks and its structure. Dust blocks short wavelengths of visible light but lets red light and infrared light through.