AST201H1 Lecture Notes - Lecture 12: Luminosity Distance, Stellar Classification, Thermal Radiation

• School: UTSG
• Department: Astronomy & Astrophysics
• Course: AST201H1
• Professor: Macdonald

Document Summary

Properties of a star: what we want to know: composition - spectral lines, distance - parallax, mass size, history/future. Properties of a star: what we can measure position on sky spectrum (light: apparent brightness colour spectral lines, changes in these things. Thermal radiation: hot things glow: anything that is warm glows the temperature of the object effects its spectrum. Luminosity classes a star"s luminosity tells us the intrinsic brightness of the star. Parallax recap: distant things move very little left vs right eye: nearby things move a lot. Clicker quiz: star a moves 10x more than star b, compared to background stars. from this we can conclude that : star b is 10x further away than star a the bigger the shift the bigger the distance. Clicker quiz: star a and star b have the same apparent brightness. To have same apparent brightness, star b must be .