Principles and Perspectives in Cosmochemistry (eBook)

Principles and Perspectives in Cosmochemistry 
3 
Preface 5
Contents 8
Part I Stellar Structure, Nucleosynthesis and Evolution of Low and Intermediate-mass Stars 15
Stellar Structure and Evolution: An Introduction 16
1 Introduction 16
2 The Hertzsprung–Russell Diagram 18
2.1 Cluster Diagrams 20
2.2 The Temperature–Luminosity Relation 24
2.3 The Mass–Luminosity and Mass-Radius Relations 24
3 Stellar Evolution – A Sneak Preview 24
4 Stellar Time Scales 28
4.1 Dynamical (Free-Fall) Time 28
4.2 Thermal (Kelvin) Time 29
4.3 Nuclear Time 30
4.4 Diffusion Time 30
4.5 Comparative Timescales 31
5 Equations of Stellar Structure 32
5.1 Mass Continuity 33
5.2 Hydrostatic Equilibrium 34
5.3 Virial Theorem 34
5.4 Energy Conservation 37
5.5 Energy Transport 38
5.6 The Equations of Stellar Structure 40
6 Equations of Stellar Evolution 42
6.1 Thermal Expansion (Contraction) 42
6.2 Nucleosynthesis 42
6.3 Mixing 42
7 Equation of State 43
7.1 Gas Laws 43
7.2 Pressure 44
7.3 The Classical Ideal Gas 45
7.4 Mean Mass per Particle 45
7.5 Degenerate Electron Gas 46
7.6 Photons 47
7.7 Total Pressure 48
8 Stellar Opacity 49
8.1 Bound-Bound Absorption 50
8.2 Bound-Free Absorption 51
8.3 Free-Free Absorption 51
8.4 Electron Scattering 52
8.5 Total Absorption Coefficient 52
8.6 Electron Conduction 55
9 Thermonuclear Physics 55
9.1 Fusion 56
9.2 Reaction Rates 58
9.3 Reaction Networks 59
9.4 Nucleosynthesis of elements 64
9.5 Neutrinos 65
10 Approximate Solutions 66
10.1 Polytropic Gas Spheres 66
10.2 Clayton Models 67
10.3 Minimum Mass of a Star 70
10.4 Maximum Mass of a Star 71
11 Methods for Numerical Solution 72
11.1 Shooting Method 72
11.2 Difference Method 73
12 Stellar Evolution 75
12.1 Pre-Main-Sequence Evolution 75
12.2 The Zero-Age Main Sequence 76
12.3 Evolution of a 5M Star 79
12.4 Evolution at Other Masses 81
13 Stellar Remnants 81
13.1 White Dwarfs 81
13.2 Type II Supernovae 83
13.3 Neutron Stars 86
14 Horizontal Branch Stars 87
14.1 Horizontal Branch Stars in Clusters and the Field 88
14.2 Theoretical Models for Horizontal Branch Stars 88
14.3 Evolution of Horizontal Branch Stars 91
14.4 Extreme Horizontal Branch Stars 92
14.5 The Origin of EHB Stars 93
14.6 Extreme Horizontal Branch Stars in other Galaxies 97
15 Late Stages of Stellar Evolution: Hydrogen-Deficient Stars 97
15.1 Population I and Massive Hydrogen-Deficient Stars 98
15.2 Low-Mass Hydrogen-Deficient Supergiants 101
15.3 Hydrogen-Deficient Subdwarfs. 104
15.4 Central Stars of Planetary Nebulae 105
15.5 White Dwarfs 107
15.6 Post-AGB evolution 108
15.7 Double-Degenerate Mergers 111
16 Conclusion 112
References 112
Nucleosynthesis of Low and Intermediate-mass Stars 119
1 Introduction 119
2 Some preliminaries 121
3 Evolution and nucleosynthesis prior to the AGB 124
3.1 The Evolution of a 1M Star 125
3.2 The Evolution of a 5M Star 129
3.3 The First and Second Dredge-up 131
4 Evolution during the AGB 135
4.1 Carbon stars 143
4.2 Luminosity variability 143
4.3 Mass loss 144
5 Nucleosynthesis during the AGB 144
5.1 Nucleosynthesis in the hydrogen-burning shell 145
5.2 Nucleosynthesis during thermal pulses 146
5.3 Comparison with observations: Intershell abundances 150
5.4 Fluorine production in AGB stars 152
5.5 Extra-mixing process on the AGB 154
5.6 Hot bottom burning 155
5.7 The production of lithium by HBB 156
5.8 HBB and the C, N, and O isotopes 157
5.9 HBB and the Ne, Mg, and Al isotopes 160
5.10 Yields from AGB stars 160
6 The slow neutron-capture process 165
6.1 Neutron sources operating in AGB stars 166
6.2 Partial mixing and the formation of 13C pockets 167
6.3 The s-process in massive AGB stars 169
7 Concluding remarks 170
References 171
Spectral Classification: Old and Contemporary 177
1 Historical Account of Spectral Classification 177
1.1 Luminosity Effects in Stellar Spectra 178
2 Classification Criteria for various spectral types 180
O-type Stars 180
B-type Stars 180
A-type Stars 182
F-type Stars 183
G-type Stars 183
K-type Stars 183
Carbon Stars 184
M-type Stars 185
S-type Stars 186
3 New Spectral types L and T 186
3.1 The T dwarfs 186
4 Modification of MK system 187
5 Contemporary methods of spectral classification 189
References 191
Part II Massive Stars, Core Collapse, Explosive Nucleosynthesis 193
Weak Interaction Rates for Stellar Evolution, Supernovaeand r-Process Nucleosynthesis 194
1 Introduction 194
2 Some Nuclear Physics Basics 195
2.1 Shell Model 195
2.2 -decay 196
3 Overview of Core Collapse Supernovae 197
4 Weak Interaction Processes in Supernova Evolution 200
4.1 At the Pre-SN Stage 200
4.2 At the Collapse Stage 200
4.3 Mechanisms of Unblocking 201
4.4 At the late time neutrino heating stage 202
5 Nuclear Models for Calculation of the Weak Interaction Rates 203
5.1 Systematics with simple shell structure 203
5.2 Statistical models for strength 203
5.3 Microscopic Models 205
5.4 Calculations with Improved Rates 206
6 Weak Interaction Processes During pp-Chain and Solar Neutrino Problem 209
6.1 Neutrino Oscillation 211
7 -decay Rates for r-Process Nucleosynthesis 213
7.1 s-process and r-process 214
7.2 Possible r-process site 215
7.3 Models for calculation of -decay rates for r-process nuclei 216
8 Concluding Remarks 217
References 218
Massive stars as thermonuclear reactors and their explosions following core collapse 220
1 Introduction 220
2 Stars and their thermonuclear reactions 223
2.1 Why do the stars burn slowly: a look at Gamow peaks 224
2.2 Gamow peak and the astrophysical S-factor 226
3 Hydrogen burning: the pp chain 232
3.1 Cross-section for deuterium formation 233
3.2 Deuterium burning 237
3.3 3He burning 240
3.4 Reactions involving 7Be 240
Electron capture process 240
Capture reaction leading to 8B 242
4 The CNO cycle and hot CNO 243
4.1 Hot CNO and rp-process 246
5 Helium burning and the triple- reaction 247
6 Survival of 12C in red giant stars and 12C(, )16O reaction 251
7 Advanced stages of thermonuclear burning 253
7.1 Carbon burning 254
7.2 Neon burning 257
7.3 Oxygen burning 258
7.4 Silicon burning 258
8 Core collapse SNe: electron capture and neutrinos 260
8.1 Electron capture on nuclei and protons: a core thermometer 261
8.2 Number of neutrinos emitted and predictions of detections 264
9 Detected neutrinos from SN 1987A and future neutrino watch 266
10 What X-ray spectroscopy reveals about nucleosynthesis in SNe and SNRs 267
10.1 Supernova Remnant Cassiopeia A 268
X-ray grating spectra of Cassiopeia A and SN 1987A 273
10.2 Live radioactive decays in Cas A, SN 1987A 276
10.3 Other X-ray supernovae 278
References 281
The Evolution of Massive Stars and the Concomitant Non-explosive and Explosive Nucleosynthesis 287
1 Introduction 287
2 Some generalities about the evolution of massive stars 288
3 Non-explosive stellar evolution and concomitant nucleosynthesis 291
3.1 Hydrogen burning 291
3.2 Helium burning and the s-process 292
3.3 Carbon burning 293
3.4 Neon, oxygen, and silicon burning 295
4 The explosive fate of massive stars 299
5 Nucleosynthesis associated with CCSN events 303
6 The synthesis of the nuclides heavier than iron: generalities 304
6.1 The bulk Solar System composition 305
6.2 The s-, r- and p-nuclides in the Solar System 306
6.3 Isotopic anomalies in the solar composition 311
6.4 Evolution of the r-nuclide content of the Galaxy 313
6.5 Can the available isotopic data tell something about the prevalence of the s- or of the r-process at early galactic times? 315
6.6 Actinides in the Solar System, in the Local Interstellar Medium, and in stars 317
6.7 The r-nuclide content of Galactic Cosmic Rays 319
7 The astrophysics of the r-process: parametrized site-free scenarios 320
7.1 Canonical and `multi-event r-process (MER)' high-temperature models 320
7.2 Dynamical high-temperature r-process approaches (DYR) 324
7.3 A high-density r-process scenario (HIDER) 326
8 The neutrino-driven DCCSNe: a high-temperaturesite for the r-process? 327
9 Compact objects: a site for the high-densityr-process scenario? 331
10 Some brief comments on the modelling of the evolution of the r-nuclide content of the Galaxyand on nucleo-cosmochronology 333
11 The p-process: Some generalities 335
11.1 The p-process in SN IIe 337
11.2 The p-process in SNIa 341
11.3 The p-process in sub-Chandrasekhar white dwarf explosions 342
11.4 Some comments on the p-process isotopic anomaliesand chronometry 345
12 Summary and prospects 346
References 351
Part III Cosmochemistry and Solar System Abundances 354
Cosmochemistry 355
1 Introduction 355
2 Computational Methods 355
3 Cosmochemical Behaviour of the Elements 359
3.1 Refractory Elements 359
3.2 Major elements 368
3.3 Moderately Volatile Elements 369
3.4 Highly Volatile Elements 374
3.5 Atmophile Elements 376
4 Summary 384
References 385
Solar System Abundances of the Elements 386
1 Motivations to Study Solar System Elemental Abundances 386
2 Meteorites as Abundance Standards for Non-Volatile Solar System Matter 387
2.1 Composition of CI chondrites 391
3 Photospheric abundances 392
4 Recommended Present-Day Solar Abundances 402
4.1 Cosmochemical and Astronomical Abundance Scale Conversion 402
4.2 Comparison of Photospheric and Meteoritic Abundances 404
4.3 Combined Solar Abundances from CI Chondritesand Photospheric Data 405
4.4 Mass Fractions X, Y, and Z in Present-Day Solar Material 408
5 Solar System Abundances 4.56 Gyr Ago 411
6 Abundance of the Nuclides 411
References 422
Cosmochemistry: A Perspective 425