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Terrestrial Planets. II.

Terrestrial Planets. II. Earth as a planet: interior & tectonics. Dynamics of the mantle Modeling terrestrial planets. Earth interior. Earth mantle convection simulation. Labrosse & Sotin (2002). Earth interior - mantle plumes. Earth - cooling. Earth - cooling. Earth - cooling.

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Terrestrial Planets. II.

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  1. Terrestrial Planets. II. Earth as a planet: interior & tectonics. Dynamics of the mantle Modeling terrestrial planets

  2. Earth interior

  3. Earth mantle convection simulation Labrosse & Sotin (2002)

  4. Earth interior - mantle plumes

  5. Earth - cooling

  6. Earth - cooling

  7. Earth - cooling

  8. Earth interior - cooling

  9. Super-Earths

  10. Searching for Small Planets: First ‘Super-Earth’ discovered GJ 876d: -- Mass ~ 7.5 Earths Also HD 69830b: -- Mass ~ 10 Earths NASA Kepler mission: … Radii in this range after Gould et al. (2006) M = Mercury V = Venus E = Earth, etc.

  11. What would we look for and could we measure it ? Illustrate with an example - planet GJ876d:

  12. What would we look for and could we measure it ? Illustrate with an example - planet GJ876d: • GJ876: an M-dwarf (1/3 solar) with 3 planets • GJ876d - the first Super-Earth (~7.5 Earth mass) discovered (Rivera et al. 2005); • Several possible models of GJ876d ’s interior - could we distinguish among them ? • If so, what tolerances in Radius & Mass are needed ?

  13. Interiors of Super-Earths The models follow the techniques and many assumptions of Earth’s model: TWO POINTS: - Given a wide range of cosmic compositions, the mineralogy and differentiation do not vary - Their mantles will consist mostly of the newly discovered high-P phase of perovskite - post-pv Schematic temperature profile Tsuchiya et al. (2004); Valencia, Sasselov, O’Connell (2006)

  14. Post-Perovskite

  15. Interiors of Super-Earths Valencia, Sasselov, O’Connell (2006) Ocean Planet Earth-like

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

  17. Theoretical Error Budget: Planet Radius Errors: New high-P phases, e.g. ice-XI: -0.4% EOS extrapolations (V vs. BM): +0.9% Iron core alloys (Fe vs. FeS): -0.8% Viscosity, f(T ) vs. const.: +0.2% Overall the uncertainties are below 2% (at least, that’s what is known now)

  18. Interior Structure of GJ 876d 20,000 7.5 ME DENSITY (kg/m3) 12,000 Valencia, Sasselov, O’Connell (2006) 4,000 2,000 6,000 10,000 RADIUS (km)

  19. Interior Structure of GJ 876d Valencia, Sasselov, O’Connell (2006)

  20. Interior Structure of Super-Earths Valencia, Sasselov, O’Connell (2006)

  21. Interior Structure of Super-Earths Kepler error bar Valencia, Sasselov, O’Connell (2006)

  22. Interior Structure of Super-Earths Valencia, Sasselov, O’Connell (2006)

  23. What would we look for and could we measure it ? Could we measure the difference? - YES: We need at least 5% in Radius, and at least 10% in Mass. Work on tables for use with Kepler underway - masses 0.4 to 15 ME

  24. New Earths Facility Synergy with KEPLER: Provide ability to reach RV amplitudes of about 20 cm /sec. Given Porb and phase from transit, this can translate to 10% masses in the Super-Earth and Earths regime. • HARPS-NEF with Obs.Geneve • on a large telescope (WHT) • Use to measure masses, hence mean densities, for KEPLER’s candidates.

  25. New Earths Facility HARPS-South facts: Requires T and P control: 1 m/sec = 15 nm = 10-3 pix = 0.01 K = 0.01 mbar Obs. Run on a Cen B: 52 cm/sec (one night, 80% of that was p-modes), Obs. Run on HD 69830d: 20 cm/sec (over entire run).

  26. HD 69830 b,c, & d Flux HARPS: significant part of the error bars due to stellar jitter - 20 to 80 cm/sec; for HD 69830d have residuals of 20 cm/sec over the 3-year run. Lovis, Mayor, Pepe, et al. (2006) Wavelength (microns)

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