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Tidal Dynamics of Transiting Exoplanets Dan Fabrycky UC Santa Cruz 13 Oct 2010 Photo: Stefen Seip, apod/ap040611 At: The Astrophysics of Planetary Systems:

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Presentation on theme: "Tidal Dynamics of Transiting Exoplanets Dan Fabrycky UC Santa Cruz 13 Oct 2010 Photo: Stefen Seip, apod/ap040611 At: The Astrophysics of Planetary Systems:"— Presentation transcript:

1 Tidal Dynamics of Transiting Exoplanets Dan Fabrycky UC Santa Cruz 13 Oct 2010 Photo: Stefen Seip, apod/ap At: The Astrophysics of Planetary Systems: Formation, Structure, and Dynamical Evolution Tidal Dynamics of Transiting Exoplanets

2 Why tides? Cumming+08 Hot Jupiters are a Sub-class

3 Why transits? 1) m p, R p, (a p /R * ) 2)  / Period (days) Mass [M J ]  Dynamics not foreseen? { Spin-orbit  migration (Queloz+2000) TTV/TDV (Miralda-Escude 2002) Tidal consumption (Sasselov 2003) Pont et al. 2010

4 Historic perspective: disk migration is destructive (Goldreich & Tremaine 1980, Ward 1997) Stop it near the star? (Lin et al. 1996) That gives >10x too many hot Jupiters (Ida talk) Solution: Disk migration does not produce most hot Jupiters. Disk migration? Cumming+08

5 Alternative: tidal dissipation Rasio & Ford 1996, Wu & Murray 2003, Matsumura, Peale, & Rasio 2010

6 Kozai Movie

7 But will tidal heating destroy the planet? Disruption possible (E t >E b ) for Maximum tidal input: Planet binding energy: work in progress with Doug Lin & Tsevi Mazeh

8 Circularization with Overflow… In Words Dynamics slowly lowers the periapse Circularization takes hundreds of orbits The planet inflates slowly to the Roche Lobe It overflows gently through L 1 while circularizing Transfer of angular momentum raises periapse

9 In equations Energy conservation A.M. conservation Roche-Lobe filling 

10 In a picture

11 Circularization with Overflow Allows the survival of tidally migrating/inflating planets May explain M p -P correlation (Mazeh et al relation): Lower mass planets  less binding energy  overflow more  back away from the star further This model is doomed to succeed.

12 Inclination expectations remain aligned get misaligned Inclination to stellar equator?

13 Disk migration Kozai cycles with tidal friction Planet-planet scattering with tidal friction Fabrycky & Tremaine 07 Wu+07 Nagasawa+08 e.g., Cresswell+07 Also, resonant-pumping (Yu & Tremaine 01, Thommes & Lissauer 03) Inclination expectations

14 Comparison to Observations Kozai Planet-Planet Scattering observations (Triaud+10)

15 New Correlations Host’s convective zone mass Tidal torque Winn, Fabrycky, Albrecht, Johnson 2010 (see also Schlaufman 2010)

16 Clear and Present Danger: Planetary Consumption Tidal calculations assuming only the convective envelope feels torque from the planet. The planet can realign the star’s observable photosphere. The photosphere is not spun-up, due to magnetic braking. The planet is doomed.

17 Let’s look to Astrophysics

18 Radiative-Convective Decoupling Decoupling was predicted theoretically (Pinsonneault+1987) Observed stellar rotation periods as a function of age suggest decoupling (e.g., Irwin & Bouvier 2009) BUT: Coupling apparently observed in the Sun Howe 2009, from helioseismology  [10 -4 rad/s] r/R star

19 Conclusions Fundamental indicators of hot Jupiter formation: –The pile-up and the mass-period relation within it –Spin-orbit alignment statistics and correlations Circularization from high eccentricity is likely the dominant channel. Tides in the star might damp obliquities, but it is time to entertain a variety of ideas.

20 Theory of Secular Resonance  frequency g frequency 

21 i   HD 80606: Secular Resonance during Kozai cycles with tidal friction


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