Stan OwockiFundamentals of Astrophysics

Chapter 6: Composition and Ionization from Stellar Spectra

6.1 Spectral line absorption and emission6.2 Elemental composition of the Sun and stars 6.3 Stellar spectral type6.4 Hertzsprung-Russell (H-R) diagram6.5 Questions and exercises

I Stellar Properties

Sun’s spectrum

Continuum vs. line emission/absorption

Hydrogen atom

Energy levels

emission line spectrum=>

absorption line spectrum=>

Lyman series

Balmer series

Paschen series

Bohr atom

Elemental Abundances

by number:

by mass:

Sequence of spectral types

Hertzsprung-Russell diagram

Observed H-R diagram from Gaia satellite

Ch. 6 Quick Questions