Exoplanets: Detection, Formation, Properties, Habitability (Springer-Praxis Books in Astronomy and Planetary Sciences)

335 Pages·2008·24.83 MB·English

by  John W. Mason

Exoplanets
Detection,Formation,Properties,Habitability
John W. Mason (Editor)
Exoplanets
Detection, Formation, Properties, Habitability
Published inassociationwith
PPrraaxxiiss PPuubblliisshhiinngg
Chichester, UK
Editor
Dr John W. Mason
Olympus Mons
51 Orchard Way
Barnham
West Sussex PO22 0HX
UK
Front cover illustrations: (Main image)A computer-generated simulationofa Jupiter-
sized exoplanet shown crossing in front of the disk of its parent star. Image courtesy
Jeffery Hall, Lowell Observatory. (Smaller image) Artist’s concept of a planetary disk
around a brown dwarf. Image courtesy NASA/JPL-Caltech/T.Pyle (SSC).
Backcoverillustrations:(Top)Artist’simpressionofaSaturn-massplanetorbitingthe
sun-like star HD149026, with atmosphere based on models by James Cho. Image
courtesy Greg Laughlin, University of California, Santa Cruz. (Bottom) Artist’s
impression of the Jupiter-sized planet discovered transiting a star 500 light-years
from Earth. Image courtesy Jeffery Hall, Lowell Observatory.
SPRINGER–PRAXIS BOOKS IN ASTRONOMY AND PLANETARY SCIENCES
SUBJECTADVISORYEDITORS:PhilippeBlondel,C.Geol.,F.G.S.,Ph.D.,M.Sc.,SeniorScientist,Department
ofPhysics,UniversityofBath,UK;JohnMason,B.Sc.,M.Sc.,Ph.D.
ISBN 978-3-540-74007-0 Springer Berlin Heidelberg New York
Springer is part of Springer-Science+Business Media (springer.com)
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# Praxis Publishing Ltd, Chichester, UK, 2008
Printed in Germany
The use of general descriptive names, registered names, trademarks, etc. in this
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Cover design: Jim Wilkie
Author-generated LaTex, processed by EDV-Beratung, Germany
Printed on acid-free paper

Contents
Editor’s Preface .................................................... xi
List of contributors ................................................. xix
1 Detection Methods and Properties of Known Exoplanets
Patrick G. J. Irwin.................................................... 1
1.1 Introduction..................................................... 1
1.2 Detection of Extrasolar Planets .................................... 1
1.2.1 Radial Velocity Detections ................................. 2
1.2.2 Astrometry .............................................. 4
1.2.3 Transit Detections ........................................ 4
1.2.4 Microlensing ............................................. 6
1.3 Properties of Observed Extrasolar Planets........................... 7
1.4 Sensitivity and Future Methods for Detection of Extrasolar Planets .... 12
1.4.1 Transit Programmes....................................... 13
1.4.2 Direct Optical Detection ................................... 14
1.5 Conclusions ..................................................... 16
References ........................................................... 17
2 Doppler Exoplanet Surveys: From Single Object to Multiple
Objects
Jian Ge.............................................................. 21
2.1 Introduction..................................................... 21
2.2 Description of the Doppler Method................................. 21
2.2.1 The High Resolution Cross-Dispersed Echelle Method ......... 22
2.2.2 The Dispersed Fixed-Delay Interferometer Method ............ 25
2.3 Main Results from Single Object Doppler Planet Surveys ............. 28
2.3.1 Main Conclusions on Giant Planets ......................... 29
2.3.2 New Super-Earth Mass Planet Results....................... 30
2.4 Science Needs for Multiple Object Doppler Planet Surveys ............ 30
2.5 Early Results from a Multi-Object Doppler Planet Survey............. 32
2.6 New Planet Science to be Addressed by Next Generation Multi-Object
RV Planet Surveys ............................................... 37
2.6.1 Giant Planet Science ...................................... 37
2.6.2 Comparison with Other Planet Surveys ...................... 39
2.6.3 Super-Earth Mass Planets.................................. 40
vi Contents
2.7 Conclusions ..................................................... 41
References ........................................................... 42
3 Detection of Extrasolar Planets by Gravitational Microlensing
David P. Bennett ..................................................... 47
3.1 Introduction..................................................... 47
3.2 Gravitational Microlensing Theory ................................. 48
3.2.1 The Single Lens Case...................................... 48
3.2.2 Multiple Lens Systems..................................... 51
3.3 Planetary Microlensing Events..................................... 53
3.3.1 Planetary Caustic Perturbations ............................ 54
3.3.2 Stellar Caustic Perturbations ............................... 55
3.3.3 Finite Source Effects ...................................... 56
3.4 Planetary Parameters from Microlensing Events ..................... 58
3.4.1 Angular Einstein Radius ................................... 59
3.4.2 Microlensing Parallax...................................... 64
3.4.3 Planetary Orbits.......................................... 64
3.5 Observational Programs .......................................... 65
3.5.1 Early Observational Results ................................ 66
3.5.2 Microlensing Planet Detections ............................. 67
3.6 Future Programs................................................. 79
3.6.1 The Ultimate Exoplanet Census: Space-Based Microlensing..... 81
References ........................................................... 83
4 Formation and Evolution of Terrestrial Planets in Protoplanetary
and Debris Disks
George H. Rieke ...................................................... 89
4.1 Overview ....................................................... 89
4.2 Protoplanetary Disks ............................................. 91
4.2.1 Disk Behaviour ........................................... 91
4.2.2 Terrestrial Planet Formation ............................... 95
4.3 Debris Disks .................................................... 97
4.3.1 Debris in the Solar System ................................. 98
4.3.2 Theoretical Background.................................... 99
4.3.3 Evolution ................................................ 99
4.3.4 Spectral Energy Distributions ..............................101
4.3.5 Imaging .................................................103
4.3.6 Dependence on Stellar Mass, Metallicity, and Presence of
Companions..............................................105
4.4 Conclusion ......................................................105
References ...........................................................106
Contents vii
5 The Brown Dwarf – Exoplanet Connection
I. Neill Reid, Stanimir A. Metchev ......................................115
5.1 Introduction.....................................................115
5.2 Intrinsic Properties of Brown Dwarfs ...............................117
5.2.1 Brown Dwarf Evolution....................................117
5.2.2 Observed Characteristics...................................120
5.2.3 Classifying Brown Dwarfs and Exoplanets....................123
5.3 Observational Techniques for Identifying Low-mass Companions .......124
5.3.1 Direct Imaging Surveys ....................................124
5.3.2 Radial Velocity ...........................................127
5.3.3 Astrometric Surveys.......................................129
5.3.4 Photometric Methods: Eclipsing Binaries.....................130
5.3.5 Summary ................................................132
5.4 Brown Dwarfs as Companions .....................................132
5.4.1 Stellar Binary Systems ....................................133
5.4.2 Solar-Type Stars..........................................135
5.4.3 Low Mass Binaries ........................................136
5.4.4 Summary ................................................139
5.5 Future Work ....................................................141
5.5.1 Direct Detection of Transiting Planets .......................142
5.5.2 High Contrast Imaging ....................................142
5.5.3 Wide Field Imaging Surveys................................143
5.5.4 Radial Velocity and Astrometric Surveys.....................145
5.5.5 Brown Dwarf Atmospheres .................................145
5.6 Summary and Conclusions ........................................146
References ...........................................................146
6 Close-Orbiting Exoplanets: Formation, Migration Mechanisms
and Properties
Hugh R.A. Jones, James S. Jenkins & John R. Barnes ....................153
6.1 Introduction.....................................................153
6.2 51 Pegasi as a Prototypical Close-Orbiting Exoplanet.................155
6.3 Transit Discovery of Close-Orbiting Planets .........................156
6.4 Orbital Characteristics of Close-Orbiting Planets.....................156
6.4.1 Exoplanetary Mass Function ...............................158
6.4.2 Exoplanetary Eccentricities ................................159
6.4.3 The Parent Stars of Close-Orbiting Exoplanets are Metal-Rich..161
6.5 Migration and Formation of Exoplanets.............................162
6.5.1 Planet Formation .........................................163
6.5.2 Migration and Evolution...................................165
6.6 Close-Orbiting Planet Atmospheres ................................167
6.7 Composition ....................................................169
6.8 Future..........................................................169
6.8.1 The Hunt for Terrestrial Planets ............................170
References ...........................................................172
viii Contents
7 Dynamics of Multiple Planet Systems
Rory Barnes .........................................................177
7.1 Introduction.....................................................177
7.1.1 Planetary Orbits..........................................178
7.1.2 Observational Constraints..................................178
7.2 Review of Orbital Theory .........................................179
7.2.1 Analytical Methods .......................................180
7.2.2 N-body Integrations.......................................186
7.2.3 Dynamical Stability and Chaos .............................187
7.3 Dynamics of Individual Systems ...................................189
7.4 Distributions of Dynamical Properties ..............................194
7.4.1 Types of Interactions ......................................195
7.4.2 Frequency of Mean Motion Resonances ......................195
7.4.3 Apsidal Motion ...........................................195
7.4.4 Proximity to Dynamical Instability..........................196
7.5 Conclusions .....................................................201
References ...........................................................202
8 Searching for Exoplanets in the Stellar Graveyard
Steinn Sigurdsson .....................................................209
8.1 The Discovery of Extrasolar Planets................................209
8.2 Planets Around Pulsars...........................................210
8.2.1 Pulsars ..................................................210
8.2.2 Searches for Planets .......................................211
8.2.3 Origin of the Pulsar Planets................................213
8.2.4 Planet in Messier 4........................................214
8.3 Planets Around White Dwarfs .....................................216
8.3.1 Timing of Pulsating White Dwarfs ..........................219
8.4 Future Prospects.................................................220
References ...........................................................221
9 Formation, Dynamical Evolution, and Habitability of Planets in
Binary Star Systems
Nader Haghighipour ...................................................223
9.1 Introduction.....................................................223
9.2 Dynamical Evolution and Stability .................................227
9.2.1 Stability of S-type Orbits ..................................229
9.2.2 Stability of P-type Orbits ..................................234
9.3 Planet Formation in Binaries ......................................236
9.4 Habitability .....................................................246
9.5 Future Prospects.................................................251
References ...........................................................252
Contents ix
10 Planetary Environmental Signatures for Habitability and Life
Victoria S. Meadows ..................................................259
10.1 Introduction: Astrobiology and Habitability .........................259
10.1.1 Habitable Zones ..........................................260
10.1.2 A Diversity of Habitability .................................261
10.2 Techniques and Space Missions for Direct Detection of Earth-Sized
Worlds .........................................................263
10.2.1 Infrared Nulling Interferometer .............................263
10.2.2 Visible Light Coronograph .................................263
10.3 Remote Detection of Planetary Characteristics.......................264
10.3.1 Planetary System Environmental Characteristics..............264
10.3.2 Photometry and Photometric Variability.....................265
10.3.3 Remote Sensing Spectroscopy ..............................266
10.4 Biosignatures: The Global Footprints of Life.........................272
10.4.1 Atmospheric Biosignatures .................................273
10.4.2 Surface Signatures ........................................275
10.4.3 Temporal Signatures ......................................276
10.4.4 Sensitivity to Cloud Cover .................................278
10.5 Biosignature Detection ...........................................278
References ...........................................................280
11 Moons of Exoplanets: Habitats for Life?
Caleb A. Scharf.......................................................285
11.1 Introduction.....................................................285
11.1.1 Habitable Zones and Exoplanets ............................289
11.2 Moon Formation.................................................290
11.3 Environmental Conditions of Moons................................291
11.3.1 Tidal Heating and Boosted Temperatures ....................296
11.4 Moon Detection .................................................297
11.5 Life on Exomoons................................................298
11.6 Summary .......................................................299
References ...........................................................300
Index...............................................................305