Beforewestart

  Briefintroduc-onoftheplansandideasfortheplanetarygroup(LinkswithChileanUniversi-esJC/OneDayWS;PlanetarySystemsII)

  Visitorsencouraged

  Memberstoprovidecross‐trainingtoPAOmembers(PAOisaplacetotalkaboutscience!PlanetsisakeydriverforthefutureofESO,weshouldtogrowexper-seandinterestonthefield)

  Frequencyofthemee-ngs–Everytwoweeksseemsagoodnumber

Spin‐orbitanglemeasurementsforsixsoutherntransitingplanetsAmauryTriaudetal

http://www.superwasp.org/documents/triaud2010_rossiter.pdf

“Thisisarealbombwearedroppingintothefieldofexoplanets,”saysAmauryTriaud,aPhDstudentattheGenevaObservatorywho,withAndrewCameronandDidierQueloz,leadsamajorpartoftheobserva-onalcampaign.

WHY???

Rossiter‐McLaughlineffect

Howaboutthespectroscopictransit?

  Weallknowhowaphotometrictransitlookslike

Radialvelocity

Thetransi/ngobjectblocksthestellardiskproducingashi:intheRV

Theamplitudeofthiseffectisrelatedtothegeometryandtotherota/onalvelocity

Ohtaetal.(2005)

Ohtaetal.(2005)

Thus:

• forβ=0theplanetaryorbitisperpendiculartothestellarrota/onaxis;• Forβ=90theorbitisalongtherota/onaxis

• Forβ>90theorbitalmo/onisretrograde

λ(orβ inTriaud’spaper)istheprojectedspinorbitmisalignmentangle.

Gaudi&Winn2006,ApJ

Measurements

  Globalfiangofphotometrictransit,RVcurveandspectroscopictransit

  6transi-ngplanetsfoundbyWASPwerestudiedinthepaper

  3ofthemhaveβ>90(retrogradeorbits)

  3othershaveβ~0

WASP‐15b;β=139 WASP‐5b;β~0

AmauryTriaudetal

Therealmisalignment

  Theymeasuredthesky‐projectedspin‐orbitangle

  Therealangleψ ises-matedusingtheargumentthatthespinaxisisisotropicallydistributed

  cosψ=cosIcosi+sinIcosβ

  Iistheinclina-onofthestellarspinaxisandItheinclina-onoftheplanet’sorbitalaxis.

AmauryTriaudetal

Discussion

  26RMeffectshavebeenobservedsofar

  14haveβ<22andareconsideredaligned

  Theyfindthatthereisa82%probabilitythatψis>22deg(SolarSystemcase)

AmauryTriaudetal

KozaiMechanism

  Inapresenceofa3rddistantbody,iftheorbitalplaneoftheinnerbinaryisnotalignedwiththeouterorbit,thee_inandtheinclina-onbetweenthetwoorbitswilloscillateincycles.

  KC+Tidalfric-onthee_inbecomeslargesothatintheperiastronpassage-destakeoverforawhileworkingtowardsacircularorbit.

Theoreticalprediction

Thepredic-onforthemisalignmentspin‐planetaryorbitForsystemswithathirdcompanion.(FabryckyandTremaine2007)

Itmatchesbeau-fullytheobserva-ons!

Conclusions

  RMmeasurementsobtainedwithhighaccuracyRVdatasuggestthat>80%ofthehot‐jupitersaremisalignedwithanglessome-mes>90%

  Forma-onofhot‐jupitersviamigra-onrequiresinterac-onswiththediscandthereforecoplanarity

  Kozaimechanismwouldcausetheinnerorbittooscillate(e_in,inclina-on)andreducetheorbitalperiod.

  Thepredicteddistribu-onofspin‐orbitangleisverysimilartotheonedrawnfromsta-s-calargumentstransformingtheβdistribu-on.