CircumbinaryPlanets/DisksDongLai

CornellUniversity

--Simula6onsofcircumbinaryaccre6on:EccentricDisks,Ang.Mom.TransferDiegoMunoz&DL2016RyanMiranda,Munoz,DL2016--Misalignedcircumbinaryplanetsaroundcompact(<5day)binaries.Munoz&DL2015--Destruc6onofcircumbinaryplanetsbyevec6onresonanceWenruiXu&DL2016

7/6/2016,ExoplanetsI,Davos

Hiding Planets Behind a Big Friend

Dong Lai & Bonan Pu Cornell University

Exoplanets I Conference, Davos, July 6, 2016

Multi-Planet System with an External Companion

arXiv:1606.08855

Kepler:4700planetsin3600systems (mostlysuper-earthorsub-neptunes,<200days)

NumberofTransiGngplanets

Num

bero

fsystems

(5/17/2016)

ObservedTransitMulGplicityDistribuGonF(Ntran)

F(Ntran)===>theunderlyingmulGplicitydistribuGon&mutualinclinaGonsDegeneracycanbebrokenbyRVdata(Tremaine&Dong12)Transitdura6onra6o(Fabrycky+14)

Keplercompactsystemsareflat,withmutualinclinaGondispersion<2degrees

Lissauer+11,Tremaine&Dong12,Figueira+12,Fabrycky+14;Fang&Margot12

ModelswithsingleinclinaGondispersion(e.g.inRayleigh)donotfitwell:Under-predictKeplersinglesbyafactorof>2

Lissauer+11,Johansen,Davies+12,Weissbein+12,Ballard&Johnson+16

NumberofTransiGngplanets

Num

bero

fsystems

Red:best-fittomu6ple-transitplanetsystemswithsingleInclina6ondispersion

“KeplerDichotomy”

KeplersystemsconsistofatleasttwounderlyingpopulaGons:(1) SystemsN>~6planetswithsmallmutualinclina6ons(~2degrees):AccountformostofKeplerMul6’s(Ntran>1)

(2)Systemswithfewerplanetsorwithhighermutualinclina6ons:Accountfora(large)frac6onKeplersingles(Ntran=1)

“KeplerDichotomy”

KeplersystemsconsistofatleasttwounderlyingpopulaGons:(1) SystemsN>~6planetswithsmallmutualinclina6ons(~2degrees):AccountformostofKeplerMul6’s(Ntran>1)

(2)Systemswithfewerplanetsorwithhighermutualinclina6ons:Accountforalargefrac6onKeplersingles(Ntran=1)

Otherevidencethat(some)Keplersinglesare“special”:(1)  “singles”havehigherstellarobliqui6es(Morton&Winn14)(2)  Mul6’shavemoredetectableTTVsthan“singles”(Xie,Wu&Lithwick14)(3)  10-30%ofsingleshavehighere’s(JiweiXie’sposter)(4)  Single“HotEarth”excess(JasonStaffen’stalk)

OriginofKeplerDichotomy

--Primordialin-situassemblyofplanetesimaldiskswithdifferentmass&densityprofile(Mariarty&Ballard15)--Dynamicalinstability6ghtlypackedsystem!unstable!collision/consolida6on(Volk&Gladman15;Pu&Wu15)--ExternalPerturber(Giantplanetorcompanionstar)

Two-planetsystemwithanexternalinclinedperturber

✓p

m1 m2

mp

m1,m2ini6allyco-planar…

companionstaror“coldJupiter”(e.g.producedbyplanet-planetscaperings)

✓p

m1

mpLp

L1

⌦1p ⇠ mp

M?

✓a1ap

◆3

n1 / mp

a3pa3/21

Precessionof“1”drivenby“p”:

m1 m2

mp

⌦1p

⌦2p

!12

!21

Mutualinclina6oninducedbyperturberdependsonCouplingParameter

/ mp

a3p

MaximumMutualInclinaGonInducedbyexternalperturber

✓p = 10�

mp

m1 m2

⌦1p

⌦2p

!12

NodalPrecessionResonance

ResonanceFeature:exists when m2 & m1

✏12 ⇠ 1

In the m2 � m1 limit:Resonance occurs at ⌦2p = ⌦1p + !12 or ✏12 = 1

ResonanceFeature:✏12 ⇠ 1

Can produce much larger mutual inclination than ✓p

ResonanceFeature:✏12 ⇠ 1

Can produce much larger mutual inclination than ✓p

MulG-planetsystemwithanexternalinclinedperturber

✓p

m1 m2

mp

m3 m4

4planetsystemwithanexternalperturber

averaged coupling parameter / mp/a3p

dispersionofmutualinclination

4planetsystemwithanexternalperturber

averaged coupling parameter / mp/a3p

dispersionofmutualinclination

Recap:

✓p

m1 m2

mp

Anunderstandingandsemi-analyGcexpressionforthemutualinclina6onofmul6-planetsinducedbydistantperturber

For ✏12 & 2 : ✓12 ⇠ 2✓pFor ✏12 . 0.3 : ✓12 ⇠ ✏12 sin 2✓p

e.g., for m2 ⇠ m� at a2 ⇠ 0.3 au

1MJ perturber at 3 au gives ✏12 ⇠ 0.3

✏12 =⌦2p � ⌦1p

!12 + !21⇠

✓mp

m2

◆✓a2ap

◆3

for m2 ⇠ m1, a2 ⇠ 1.5a1

ApplicaGon:“Evaluate”/constrainexternalperturberofobservedsystems

Examples:(seeDL&Puformore)

Kepler-68:Twosuper-Earthsat0.06,0.09au,1MJplanetat1.4auisweakKepler-56:…WASP-47:...Kepler-48:Threetransi6ngplanets(0.012,0.046,0.015MJ)at0.053,0.085,0.23au,

>2MJcompanion(Kepler-48e)at1.85au(Marcy+14) "Kepler-48emustbealigned<2degree

Kepler-454:onesuper-Earthat0.1auwitha>5MJat524days(Gepel+16) "anyneighbortotheinnerplanetcouldbestronglymisalignedbythegiant (Thiscouldofmul6-planetsystemthathasbeenturnedintoKeplersingle byanexternalgiantplanet)

Iamhappytoreceiveemailaboutothersystems(starorgiantplanetperturbers)

WhataboutKeplerDichotomy?

Asignificantfrac6onofKeplersingles(Ntran=1)are/weremul6-planetsystemsthathavebeenmisaligned(inmutualinclina6ons)ordisruptedbyexternalperturbers(coldgiantplanetsorstellarcompanions)

ColdGiantPlanets:Somehavebeenfound,butgeneralcensusnotclear?

(50%ofHJs/WJshave1-20MJcompanionat5-20au;Bryanetal2016)

StellarCompanions:J.Wangetal(2015):~5%ofKeplermul6shavestellarcompanion1-100au

(4xlowerthanfieldstars)

Morestudiesareneeded.

GeneralComment:InfluencesofExternalPerturberson(Inner)PlanetarySystems

---Mutualinclina6ons(DL&Pu2016)---Forma6onofHotJupitersandWarmJupiters(high-emigra6on)(manypapers…)e.g.High-emigra6oninducedbystellarcompanioncontrinutes

~10-15%ofHJs(Petrovich15;Anderson,Storch&DL16;Munoz,DL+16)---Evec6onresonance(Touma&Sridhar15;Xu&DL16)