Table of Contents
Preface vii
About the Authors xi
Acknowledgments xiii
Background xix
1 Binary Stars 1
1.1 Classification 1
1.2 Observations 3
1.3 Planets in Binary Star Systems 5
2 Orbital Motion in Binary Star Systems 9
2.1 Types of Planetary Motion 11
2.2 Stability of Circular Planetary Orbits 13
2.2.1 S-type motion 13
2.2.2 P-type motion 17
2.3 Stability of Eccentric Planetary Orbits 19
2.3.1 S-type motion 20
2.3.2 P-type motion 23
3 Perturbations in Multi-Planet Binary Star Systems 25
3.1 Mean Motion Resonances 26
3.1.1 The disturbing function 26
3.1.2 The small divisor 27
3.1.3 Resonance location 28
3.2 Secular Resonances 29
3.2.1 The averaged disturbing function 29
3.2.2 Secular evolution of a test particle 30
3.3 New Semi-Analytical Method 31
3.3.1 Numerical part of the method 32
3.3.2 Analytical part of the method 36
3.3.3 Benefit of the method 37
4 Terrestrial Planet Formation in Binary Stars 39
4.1 Some Aspects of the Early Phase of Planet Formation 41
4.2 Terrestrial Planet Formation in the HZ 44
4.2.1 Evolution of the protoplanetary disc 48
4.2.2 Terrestrial planets in the HZ 51
4.3 Water Transport to the HZ 53
4.3.1 Statistical overview 54
4.3.1.1 The role of the secondary's mass 56
4.3.2 Water delivery due to collisions 56
4.3.3 Water loss during collisions 59
4.3.3.1 Variation in impact velocities and impact angles 59
4.3.4 Water transport statistics: Binary versus single star 64
4.4 Summary 66
5 Implications of Stellar Binarity 69
5.1 S-types: Dynamical Influence of a Secondary Star 70
5.1.1 The role of the secondary's semi-major axis 72
5.1.2 The role of the eccentricities of the secondary and the planet 74
5.1.3 The role of the secondary star's mass 77
5.2 P-types: Dynamical Influence of a Secondary Star 78
5.3 Specific Stellar Influence 79
5.3.1 Stellar type: Age, evolution and activity 80
5.3.2 Stellar winds 82
5.4 Summary 84
6 Habitable Zones in Binary Star Systems 85
6.1 Habitable Zone History 86
6.2 Spectral Weights 87
6.3 Double Stars 89
6.3.1 Spectral weights for double stars 89
6.3.2 Isophote-based and radiative HZs 90
6.4 Orbital Stability 94
6.5 Insolation Variability due to Orbital Dynamics 95
6.6 Dynamically Informed Habitable Zones 101
6.6.1 Circumstellar habitable zones 102
6.6.2 Circumbinary habitable zones 105
6.6.3 Application to α Centauri and Kepler-35 107
6.7 Self-consistent Models 111
6.8 Super-habitability of Binary Star Systems 112
6.9 Summary 112
7 Habitability of Known Planets in Binary Star Systems 115
7.1 Discovered Exoplanets in Binary Systems 115
7.2 Habitable Zones 118
7.2.1 HZ of S-type systems 118
7.2.2 HZ of P-type systems 123
7.3 Gravitational Perturbations 124
7.3.1 Secular resonances 124
7.3.2 Additional effects 125
7.3.3 Discussion 126
7.4 Notes on Individual Systems 128
7.4.1 S-type systems 130
7.4.2 P-type systems 137
8 Concluding Remarks 143
8.1 Do Binary Stars Provide Habitable Environments? 143
8.2 Will Solar System-like Configurations Help? 145
Appendix: Glossary 151
Bibliography 155
Index 179
