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Earth and super-Earth Atmospheres

Earth and super-Earth Atmospheres. Dimitar Sasselov Harvard-Smithsonian Center for Astrophysics & Harvard Origins of Life Initiative. Outline. The ‘generic’ terrestrial planet. The ‘mini-Neptune’ problem Characterizing geochemical cycles. The “Tree of super-Earths”. ?. Fe -rich mantle.

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Earth and super-Earth Atmospheres

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  1. Earth and super-Earth Atmospheres Dimitar Sasselov Harvard-Smithsonian Center for Astrophysics & Harvard Origins of Life Initiative

  2. Outline The ‘generic’ terrestrial planet The ‘mini-Neptune’ problem Characterizing geochemical cycles

  3. The “Tree of super-Earths” ? Fe -rich mantle Terrestrial Planets / Dry, Rocky Planets ? ? H2O -rich mantle ? Super-Earths Ocean Planets / Water Planets ? Mini-Neptunes (Sasselov, 2008, Nantes)

  4. Earth & super-Earths vs. gas & ice giants atmosphere Matm << Mp fluxes Loss UV / photo-chemistry mantle surface / phase transition / boundary layer a well-mixed reservoir

  5. Plate tectonics on a 1 MEarth Planet:

  6. The “Tree of super-Earths” ? Fe -rich mantle Terrestrial Planets / Dry, Rocky Planets ? ? H2O -rich mantle ? Super-Earths Ocean Planets / Water Planets ? Mini-Neptunes (Sasselov, 2008, Nantes)

  7. Super-Earths vs.mini-Neptunes “Confusion region”

  8. How to distinguish mini-Neptune from super-Earth: (Miller-Ricci, Seager, Sasselov 2009)

  9. How to distinguish mini-Neptune from super-Earth: < The 3 types of atmospheres Zoomed (Miller-Ricci, Seager, Sasselov 2009)

  10. Super-Earths geochemistry, e.g. the Carbonate-silicate cycle, orSulfur cycle, etc. Planets of different initial conditions can be “driven” to a set of geochemical equilibria by global geo-cycles over geological timescales.

  11. Dominant Sulfur outgasing: with JWST SO2 CO2 No O2 or O3 , but N2 , CO2 , & CH4 . Kaltenegger & Sasselov (2009)

  12. Conclusions • Understanding the bulk geochemistry of Earth-like • planets is an achievable goal, • Use super-Earths as good proxies for Earth, • Much preparatory theory work still needed, e.g.: • Does the Sulfur (SO2) cycle have a stabilizing feedback; • What is the full catalog of possible geo-cycles, incl. on water planets (convecting Ice VII mantle); • Understand scaling of plate tectonics with mass.

  13. The “Tree of super-Earths” ? Kepler Legacy Fe -rich mantle Terrestrial Planets / Dry, Rocky Planets ? ? H2O -rich mantle ? Super-Earths Ocean Planets / Aqua Planets TESS & JWST Legacy ? Mini-Neptunes

  14. ADDITIONAL SLIDES

  15. Interior Structure: Radius & Composition Valencia, Sasselov, O’Connell (2007)

  16. Pure Iron super-Earths ? - No. - giant impacts simulations 70% Fe core: only below 4-5 MEarth Marcus, Sasselov, Hernquist, & Stewart (2009)

  17. Water super-Earths vs. Dry 3 2 1 CoRoT-7b 1 5 10 20 Zeng & Sasselov (2009)

  18. HARPS-NEF Front-end The 4.2-m William Herschel telescope, Canary Islands 1m/s in 1h for V=12 Thermal enclosures of the spectrograph

  19. HARPS Front-end The 4.2-m William Herschel telescope, Canary Islands Thermal enclosures of the spectrograph

  20. HARPS Thermal enclosures of the spectrograph

  21. A laser comb for HARPS-NEFwavelength calibration • narrow lines • coherent• equally-spaced• intense• spans optical octave Mode-lockedfemtosecond laser: essentially a 10-15s ‘strobe’ Our red astro-comb in the lab. Li et al. 2008 nm

  22. Comb lines at the telescope - FLWO, 2008

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