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Planetary Sizes

Planetary Sizes. Dimitar Sasselov. Harvard-Smithsonian Center for Astrophysics. More diversity than expected ?. Some of the Hot Jupiters do not match well models based on Jupiter & Saturn:. Gaudi (2005) w Bodenheimer et al.(2003), Laughlin et al. (2005) models. Talk Plan.

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Planetary Sizes

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  1. Planetary Sizes Dimitar Sasselov Harvard-Smithsonian Center for Astrophysics

  2. More diversity than expected ?... Some of the Hot Jupiters do not match well models based on Jupiter & Saturn: Gaudi (2005) w Bodenheimer et al.(2003), Laughlin et al. (2005) models

  3. Talk Plan • Mass-Radius Diagram of Extrasolar Planets • Transiting Planets: observational precision • Planet Ages < Stellar Ages • Interior Models: Jupiter & Saturn • The Equation of State • Chemical composition • Implications for Hot Jupiters & Planet Formation • Smaller Planets: Sizes of Super-Earths • Summary

  4. Photometry of Extrasolar Planets • Precise massive photometry: • OGLE Survey: 5 transiting planets (10b, 56b, 111b, 113b, 132b) • TrES Survey: 1 transiting planet (TrES-1) • New parameters: Radius & Mean Density • The Mass-Radius diagram • Know inclination, hence Mass & Radius are accurate; • Internal structure; insights into planet formation. • On-Off Photometry • Atmospheric transmission in spectral lines; • Measurement of planet’s daytime IR thermal emission

  5. Mass-Radius diagram: All known transiting extra-solar planets Konacki, Torres, Sasselov, Jha (2005)

  6. The Measurement Errors: • In Mass: • What we derive is: MP sini MS-2/3 • Transit phase helps in getting a good RV amplitude • Know inclination, as well • Use stellar models for MS • In Radius: • With one-band photometry - depends on MS and RS • Good multi-band photometry - drop dependence on RS

  7. OGLE-TR-113b P = 1.43 days I = 14.4 mag Radial Velocities Transit Light Curve OGLE: Udalski et al. (2003)

  8. Stellar Mass and Age: Stellar evolution track for 3 metallicities and Helium content: Age = 7 Gyrs Stars evolve from bottom zero-age main sequence Lines of constant stellar radii HD 209458 Our Sun Cody & Sasselov (2002)

  9. The Measurement Errors: • In Mass: • What we derive is: MP sini MS-2/3 • Transit phase helps in getting a good RV amplitude • Know inclination, as well • Use stellar models for MS • In Radius: • With one-band photometry - depends on MS and RS • Good multi-band photometry - drop dependence on RS

  10. OGLE-TR-10b P = 3.10 days V = 14.9 mag Radial Velocities Konacki, Torres, Sasselov, Jha (2005), green & brown points: Bouchy, Pont, Melo, Santos, Mayor, Queolz & Udry (2004) Transit Light Curve OGLE: Udalski et al. (2002)

  11. Improved photometry: Magellan telescope Holman (2004)

  12. Improved photometry: OGLE-TR-132b VLT telescope Moutou, Pont, Bouchy, Mayor (2004) Original OGLE light curve

  13. Improved photometry: HD 209458b Hubble Space Telescope - STIS Wavelength- dependent limb darkening allows more accurate RP and RS determination Charbonneau, Brown, Gilliland, Noyes (2004)

  14. Mass-Radius diagram: • Models of • the interior: • Overall Z; • Core vs. • no-core; • Age. Konacki, Torres, Sasselov, Jha (2005)

  15. Interiors of Giant Planets • Our own Solar System: Jupiter & Saturn • Constraints: M, R, age, J2, J4, J6 • EOS is complicated: • mixtures of molecules, atoms, and ions; • partially degenerate & partially coupled. • EOS Lab Experiments: • Laser induced - LLNL-NOVA • Gas gun (up to 0.8 Mbar only) • Pulsed currents - Sandia Z-machine • Converging explosively-driven - Russia (up to 1.07 Mbar)

  16. Phase diagram (hydrogen): Guillot (2005)

  17. Interiors of Giant Planets • EOS Experiment Breakthrough ? • Russian Converging explosively-driven system (CS) • Boriskov et al. (2005) • matches Gas gun & Pulsed current (Z-machine) results • deuterium is monatomic above 0.5 Mbar - no phase transition • consistent with Density Functional Theory calculation (Desjarlais)

  18. Interiors of Giant Planets Jupiter’s core mass and mass of heavy elements: The heavy elements are mixed in the H/He envelope Saumon & Guillot (2004)

  19. Interiors of Giant Planets Saturn’s core mass and mass of heavy elements: Saumon & Guillot (2004)

  20. Interiors of Giant Planets • Core vs. No-Core: • How well is a core defined? • Saturn: metallic region can mimic ‘core’ in J2 fit (Guillot 1999); • Core dredge-up - 20 Mearth in Jupiter, but MLT convection… ? • Overall Z enrichment: • Jupiter - 7x solar • Saturn - 6x solar • both have high C/O ratio

  21. More diversity than expected ?... Some of the Hot Jupiters seem to have too large, or too small, sizes: Gaudi (2005) w Bodenheimer et al.(2003), Laughlin et al. (2005) models

  22. Interiors of Hot Jupiters • Core vs. No-Core: • Core - leads to faster contraction at any age; • the case of OGLE-TR-132b > high-Z and large core? • Evaporation - before planet interior becomes degenerate enough - implications for Very Hot Jupiters; • Cores: nature vs. nurture ? - capturing planetesimals • Overall Z enrichment: • larger size, but only during first 1-3 Gyrs (opacity effects vs. molecular weight effects)

  23. Interiors of Hot Jupiters Core-less Very Hot Jupiters could lose all their mass, if parked so close early… Very Hot Jupiters They could also capture high-Z planetesimals ? OGLE-TR-56b has: Vorb = 202 km/sec, Vesc = 38 km/sec. DS (2003) w updates

  24. Dayside thermal emission: Atmospheric models for the two transiting Hot Jupiters: TrES-1 & HD209458b. Best fits for both CO and H2O seem to need high C/O values. Seager et al. (2005)

  25. Interiors of Super-Earths • Super-Earths (1-10 Mearth) • Are they there ? • What is their Mass-Radius relation(s) • Detection • Doppler shifts • Transits

  26. Interiors of Super-Earths Formation and survival of large terrestrial planets: All evidence is that they should be around: Ida & Lin (2004)

  27. Interiors of Super-Earths The models follow the techniques and many assumptions of Earth’s model: Schematic temperature profile The mantle is taken to be convecting as a single layer. Valencia, O’Connell, Sasselov (2005)

  28. Interiors of Super-Earths Mass-Radius relations for 11 different mineral compositions: Valencia, O’Connell, Sasselov (2005) 1ME 2ME 5ME 10ME

  29. Interiors of Super-Earths The Earth is the only planet model that has a liquid outer core:

  30. Summary Some basic question about the formation and structure of Hot Jupiters and other extrasolar planets remain unresolved The Mass-Radius diagram Multi-band photometry, esp. in near-IR and mid-IR Main observational results in next few years will likely all come from precise photometry Discovery of more and smaller planets: COROT (2006) KEPLER (2007) Characterization: HST & MOST (visible) Spitzer (IR) Stellar Connection: better masses, radii, and ages of the planets

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