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TheExoplanetHandbook
Exoplanet research is one of the most rapidly developing subjects in astronomy.
Morethan500exoplanetsarenowknown,andgroupsworld-wideareactivelyin-
volvedinabroadrangeofobservationalandtheoreticalefforts. Thisbooktiesto-
getherthesemanyavenuesofinvestigation–fromtheperspectivesofobservation,
technologyandtheory–togiveacomprehensive,up-to-datereviewofthefield.
All areas of exoplanet investigation are covered, making it a unique and valuable
guideforresearchersinastronomyandplanetaryscience, includingthosenewto
thesubject. Ittreatsthemanydifferenttechniquesnowavailableforexoplanetde-
tectionandcharacterisation,thebroadrangeofunderlyingphysics,theoverlapwith
relatedtopicsinsolarsystemandEarthsciences,andtheconceptsunderpinningfu-
turedevelopments. Itemphasisestheinterconnectionbetweenthevarioustopics,
andprovidesextensivereferencestomorein-depthtreatmentsandreviews.
MichaelPerrymanspent2010asaDistinguishedVisitorattheUniversityofHeidel-
bergandattheMaxPlanckInstituteforAstronomy,Heidelberg.Duringanextensive
careerwiththeEuropeanSpaceAgency,hewasthescientificleaderoftheHipparcos
spaceastrometrymission,aprojectwhichprovidedafundamentalobservationalba-
sisformanyaspectsofexoplanetstudies. HewasprofessorofastronomyatLeiden
University,TheNetherlands,between1993–2009. HechairedtheinfluentialEuro-
peanSpaceAgency–EuropeanSouthernObservatory(ESA–ESO)workinggroupon
extra-solarplanetsin2005,andhasservedonvariousnationalworkinggroupsand
strategypanelsforthefuturedevelopmentofexoplanetresearch.
The Exoplanet Handbook
MichaelPerryman
ZentrumfürAstronomiederUniversitätHeidelberg
and
Max–Planck–InstitutfürAstronomie,Heidelberg
CAMBRIDGEUNIVERSITYPRESS
Cambridge,NewYork,Melbourne,Madrid,CapeTown,Singapore,
SãoPaulo,Delhi,Dubai,Tokyo,MexicoCity
CambridgeUniversityPress
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PublishedintheUnitedStatesofAmericabyCambridgeUniversityPress,NewYork
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Informationonthistitle:www.cambridge.org/9780521765596
©M.Perryman2011
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Firstpublished2011
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ISBN978-0-521-76559-6hardback
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Contents
Preface page xi
1 Introduction 1
1.1 Thechallenge 1
1.2 Discoverystatus 1
1.3 Outlineofthetreatment 3
1.3.1 Observationaltechniques 3
1.3.2 Hoststarpropertiesandbrowndwarfs 5
1.3.3 Theoreticalconsiderations 5
1.4 Astronomicaltermsandunits 5
1.5 Definitionofaplanet 7
1.6 On-linereferencecompilations 7
2 Radialvelocities 9
2.1 Descriptionoforbits 9
2.1.1 Orbitsfromradialvelocitymeasurements 12
2.2 Measurementprinciplesandaccuracies 16
2.2.1 Introduction 16
2.2.2 Cross-correlationspectroscopy 17
2.2.3 DerivingradialvelocitiesfromDopplershifts 17
2.2.4 Wavelengthcalibration 18
2.2.5 Exposuremetering 21
2.2.6 Accuracylimits 21
2.2.7 Excludingothersourcesofperiodicity 22
2.3 Instrumentprogrammes 23
2.3.1 State-of-the-artinéchellespectroscopy 23
2.3.2 Externallydispersedinterferometry 25
2.3.3 Futuredevelopments 27
2.4 Resultstodate 28
2.4.1 Thefirstradialvelocityexoplanets 28
2.4.2 Thepresentradialvelocitycensus 28
2.4.3 On-linecompilations 28
2.4.4 Mainsequencestars 29
2.4.5 Evolvedstars 32
2.4.6 Otherstarcategories 34
2.5 Propertiesoftheradialvelocityplanets 34
2.5.1 Frequencyofmassiveplanets 35
2.5.2 Massdistribution 35
2.5.3 Orbits 36
2.5.4 Hoststardependencies 37
vi
2.6 Multipleplanetsystems 37
2.6.1 Generalconsiderations 38
2.6.2 Resonances 40
2.6.3 Long-termintegrationandsystemstability 43
2.6.4 Systemswiththreeormoregiantplanets 47
2.6.5 Systemsinmeanmotionresonance 49
2.6.6 Interactingdoubles 55
2.6.7 Non-interactingdoubles 55
2.6.8 Super-Earthsystems 55
2.6.9 Stabilityofhabitablezonesystems 55
2.7 Planetsaroundbinaryandmultiplestars 55
2.7.1 Configurationsandstability 56
2.7.2 Presentinventory 59
2.7.3 Specificexamples 60
3 Astrometry 61
3.1 Introduction 61
3.2 Astrometricaccuracyfromground 62
3.3 Microarcsecastrometry 64
3.4 Astrophysicallimits 65
3.4.1 Surfacestructurejitter 65
3.5 Multipleplanetsandmandalas 66
3.6 Modelingplanetarysystems 67
3.7 Astrometricmeasurementsfromground 68
3.8 Astrometricmeasurementsfromspace 69
3.8.1 Hipparcos 69
3.8.2 HST–FineGuidanceSensor 70
3.9 Futureobservationsfromspace 71
4 Timing 75
4.1 Pulsars 75
4.1.1 PSRB1257+12 75
4.1.2 PSRB1620–26 77
4.1.3 Otherconsiderations 78
4.2 Pulsatingstars 79
4.2.1 Whitedwarfs 79
4.2.2 Hotsubdwarfs 81
4.3 Eclipsingbinaries 81
4.3.1 Confirmedplanets 81
4.3.2 Unconfirmedplanets 82
5 Microlensing 83
5.1 Introduction 83
5.2 Description 84
5.3 Causticsandcriticalcurves 87
5.4 Otherlightcurveeffects 90
5.5 Microlensparallaxandlensmass 92
5.6 Astrometricmicrolensing 94
5.7 Otherconfigurations 95
5.8 Microlensingobservationsinpractice 96
5.9 Exoplanetresults 98
5.9.1 Individualobjects 98
5.9.2 Statisticalresults 100
5.10 Summaryoflimitationsandstrengths 100
5.11 Futuredevelopments 102
vii
6 Transits 103
6.1 Introduction 103
6.2 Transitsearches 104
6.2.1 Large-fieldsearchesfromtheground 105
6.2.2 Othersearchesfromtheground 108
6.2.3 Searchesinopenandglobularclusters 109
6.2.4 Futuresearchesfromtheground 110
6.2.5 Searchesfromspace 110
6.2.6 Follow-upobservationsfromspace 112
6.2.7 Futureobservationsfromspace 114
6.2.8 Searchesaroundspecificstellartypes 114
6.3 Noiselimits 115
6.4 Transitlightcurves 117
6.4.1 Observables 117
6.4.2 Theoreticallightcurves 117
6.4.3 Circularorbits 119
6.4.4 Eccentricorbits 121
6.4.5 Physicalquantities 123
6.4.6 Interferometricobservations 123
6.4.7 Reflectedlight 124
6.4.8 Dopplervariability 126
6.4.9 Polarisation 126
6.4.10 Secondaryeclipse 126
6.4.11 Rossiter–McLaughlineffect 127
6.4.12 Higher-orderphotometriceffects 130
6.4.13 Higher-ordertimingeffects 132
6.4.14 Higher-orderspectroscopiceffects 136
6.5 Transmissionandemissionspectroscopy 137
6.5.1 Background 137
6.5.2 Observations 139
6.6 Propertiesoftransitingplanets 143
6.6.1 Mass–radiusrelation 143
6.6.2 Observedcorrelations 146
7 Imaging 149
7.1 Introduction 149
7.2 Techniques 150
7.2.1 Activeoptics 150
7.2.2 Adaptiveoptics 150
7.2.3 Coronagraphicmasks 152
7.2.4 Specklenoise 157
7.3 Ground-basedimaginginstruments 158
7.3.1 Extremeadaptiveopticsinstruments 158
7.3.2 Extremelylargetelescopes 159
7.3.3 ImagingfromtheAntarctic 161
7.3.4 Ground-basedinterferometry 162
7.4 Space-basedimaging 162
7.4.1 Existingtelescopes 162
7.4.2 Spaceinterferometry 163
7.4.3 Thefuture:resolvedimaging 167
7.5 Imagingresults 169
7.5.1 Searchesaroundnearbystars 170
7.5.2 Searchesaroundexoplanethoststars 170
7.5.3 Searchesinsystemswithdebrisdisks 171
7.5.4 Searchesaroundwhitedwarfs 172
viii
7.6 Observationsatradiowavelengths 173
7.6.1 Astrometry 173
7.6.2 Directimaging 173
7.7 Observationsatmm/sub-mmwavelength 177
7.8 Miscellaneoussignatures 177
7.8.1 Planetaryandproto-planetcollisions 177
7.8.2 Collisionaldebris 178
7.8.3 Accretionontothecentralstar 178
7.8.4 Gravitationalwavemodulation 179
8 Hoststars 181
8.1 Knowledgefromastrometry 181
8.1.1 Hipparcosdistancesandpropermotions 181
8.1.2 Nearbystarcensus 181
8.1.3 Galacticcoordinates 183
8.2 Photometryandspectroscopy 184
8.3 Evolutionarymodels 186
8.4 Elementabundances 188
8.4.1 Metallicity 188
8.4.2 Possiblebiases 191
8.4.3 Originofthemetallicitydifference 191
8.4.4 Refractoryandvolatileelements 194
8.4.5 Ther-ands-processelements 198
8.4.6 Thealphaelements 198
8.4.7 Lithium 199
8.4.8 Beryllium 201
8.5 Asteroseismology 201
8.5.1 Principles 201
8.5.2 Applicationtoexoplanethoststars 203
8.6 ActivityandX-rayemission 205
8.6.1 Magneticandchromosphericactivity 205
8.6.2 X-rayemission 206
8.7 Stellarmultiplicity 206
9 Browndwarfsandfree-floatingplanets 209
9.1 Browndwarfs 209
9.1.1 Theroleoffusion 209
9.1.2 Detection 209
9.1.3 Luminosityandage 211
9.1.4 Classification 212
9.1.5 Recognisingbrowndwarfs 212
9.1.6 Otherproperties 213
9.1.7 Formation 214
9.2 Free-floatingobjectsofplanetarymass 215
10 Formationandevolution 217
10.1 Overview 217
10.2 Starformation 217
10.3 Diskformation 218
10.3.1 Initialcollapse 218
10.3.2 Youngstellarobjects 219
10.3.3 Protoplanetarydisks 220
10.3.4 Debrisdisks 222
10.4 Terrestrialplanetformation 224
10.4.1 Thecontext 224
