AST201H1 Study Guide - Midterm Guide: Hydrostatic Equilibrium, Stellar Classification, Molecular Cloud

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

Document Summary

A watt is an unit of energy per unit time. So, in a 100 w rating on a light bulb tells us how much energy it is using per unit time. The sun"s luminosity tells us how bright the sun is intrinsically, just like the wattage of the light bulb. They are blackbodies, which means their colours are determined entirely by their temperatures. Their colours are determined by the colour of light they emit the most of (colour surface. As earth orbits the sun, the position of a nearby star appears to shift against the background of more distant stars. (parallax . Of all the light a star emits, earth receives only a small fraction. This small fraction determines the star"s apparent brightness or apparent magnitude as seen from. The amount of light received from a star falls with the square of our distance from it. This is called the inverse square law of light.