AST201H1 Lecture Notes - Lecture 4: Solar Mass, Roman Numerals, Protostar

• School: UTSG
• Department: Astronomy & Astrophysics
• Course: AST201H1
• Professor: Marija Stankovic

Document Summary

There is a limit (150 solar masses) to how big a star can be, if its not big enough it will not start the fusion. Dwarf star: all main sequence stars, even if they are huge. Luminosity class: tells us the pressure at a star"s surface. It is tightly correlated with a star"s evolutionary state, more closely related to its size. Think of it as telling us how fluffed up a star is, the fluffier, the deader. 4 subgiant: stars that have just begun their expansion into red giants, cores have shut down, hydrogen shell burning has begun. Right side of hr diagram starting from top right (i) to bottom right (v: star of luminosity class 1a all have the same luminosity. Luminosity class v have nothing in common: identification number of a star: ex: g2v g2: spectral class (letter + arabic numeral). Ex: b5ii is blue, a bright giant, and hot.