continuous spectrum 57 energy levels 13 line intensities 121 peculiar behavior 56 secondary spectrum 56 stellar spectra 55 Inner quantum number 204 Ionization 11, 15, 97 as criterion of pressure 44 potential 15 " and atomic number 20 " astrophysical 156 " and temperature of maximum 157 temperature 30 temperature scale 33, 132, 133 Ionized atom, lines of 101 Intensity of lines 23, 116 accuracy 118 estimation 117 observational material 116 Intensity scales 117 Interior of star, ionization in 18 Iron 79, 125 Isotopes 5 Law of Mass Action 105, 110 Lead 86 Level of origin of lines 134 Life of atom 21 Life of atom, astrophysical 22, 158 Limit of Balmer series 42 Line intensity, data on 121 notes on 127 unknown lines 207 Lines of unknown origin 55 Lithium 59 Low temperature conditions, stellar atmosphere 94 Magnesium 67, 122 Magnesium, compounds 67 Manganese 78, 124 Marginal appearance 105, 135, 179 Marginal appearance, observational data 181 Mass numbers of isotopes 5 Maximum of lines 106 Meteorites, composition 187 Molecule, ionization of 19 Molybdenum 84 Nickel 80 Niobium 84 Nitrogen 63, 207 Nucleus, atomic 4 , Class 162 Occurrence of elements in stars 5 Optical depth 27, 35 Origin of line spectra 11 Orion nebula, continuous spectrum 49 Oxygen 65, 207 Oxygen, compounds 66 Palladium 84 Partial electron pressure 109 Partition function 107 Percentage of stars in Draper classes 197 Photosphere 35, 47 Photoelectric ionization 159 Physical constants, astrophysical evaluation 155 Physical constants, required by ionization theory 108 Potassium 70 Pressure, atmospheres of stars 25, 34 from Balmer series limit 44 from flash spectrum 40 from ionization theory 45 from line sharpness 38 from line width 39 from radiative equilibrium 40 shift of lines 26, 38 summary 45 gradient in outer layers of star 34 Quantum number 8 Quantum relation 11 [Pg 213] Radiative equilibrium in outer layers of star 40 Radium 86 Radius and density of second type stars 36 Rare earths 85 Relative abundance of atoms, estimation 183 abundance of atoms in stellar atmosphere 177 intensities of spectrum lines 23 Reorganization time, see atomic life Residual intensity 51 Reversing layer 50 Reversing layer, mass and dimensions 47 Rhodium 84 Rubidium 81 Ruthenium 84 Rydberg constant 14, 155, 204 Saturation 52, 135 Scandium 72, 123 Series notation 55 Silicon 24, 68, 122 Silicon stars 169 Silver 84 Sodium 67 Sodium atom 8 Solar atmosphere 47 energy distribution 49 intensities 113 Space numbers for Draper classes 197 Spark spectrum 14 Special problems in stellar atmospheres 161 Spectroscopic valency electrons 10 Stark effect 26 Stars used for intensity estimates 119 Stellar atmosphere compared with earth’s crust 184 Stellar reversing layer 91 Strontium 81, 126 Strontium stars 169 Structure of absorption line 180 Subordinate lines 12 Subordinate series 99