AST201H1 Lecture : luminosity, parallax, stars, spectral class

• School: UTSG
• Department: Astronomy & Astrophysics
• Course: AST201H1
• Professor: Stefan Mochnacki

Document Summary

Luminosity: how bright- how much light the star is emitting (all) There are a great variety of techniques used to determine the distances to stars for nearby stars, we use parallax. A bigger jump distance difference- closer star, a smaller jump- further star. Earth receives only a small fraction of the sun"s light. this small fraction of light that we receive is called apparent brightness or apparent magnitude. The amount of light received from a star falls with the square of our distance from it this is called: inverse square law of light apparent brightness = luminosity/ 4(pi)(d^2) we measure the apparent brightness less light received, the further away the planet from the sun, more light received, the closer the planet from the sun. Tells us how much fusion is going on in the star- brightness. We find out the chemical composition or what the star is made of through absorption spectrum.