Circumbinary Planets/Disks - Cornell...
Transcript of Circumbinary Planets/Disks - Cornell...
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)