wavelengthflux

Spectral energy distributions of bright stars can be used to derive effective temperatures

Ay 123 Lecture I - Physical Properties

Wavelength(m)

fluxTeff

Model atmospheres of varying [Teff, g] used to fit data

Stellar Spectral Energy Distributions

Wavelength(Å)

flux

Spectral Classification

Diagnostic spectral lines act as independent measures of temperature in stellar atmosphere provided surface gravity is known

Stellar Spectra: Giants vs Dwarfs

G

K

Stars are a 2-D sequence!

Giants are slightly cooler than dwarfs of a similar spectral class with redder continua. This is because line strengths depend on Teff and g

Luminosity Classes

Overview of Stellar Evolution on H-R Diagram

Evolution During the Main Sequence

Zero Age MS