Terrestrial Planets. II.

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Terrestrial Planets. II.

1. Earth as a planet interior tectonics.
2. Dynamics of the mantle
3. Modeling terrestrial planets

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Earth interior
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Earth mantle convection simulation
Labrosse Sotin (2002)
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Earth interior - mantle plumes
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Earth - cooling
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Earth - cooling
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Earth - cooling
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Earth interior - cooling
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Super-Earths
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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.
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What would we look for and could we measure
it ?
Illustrate with an example - planet GJ876d
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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 ?

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Interiors of Super-Earths
The models follow the techniques and many
assumptions of Earths 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,
OConnell (2006)
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Post-Perovskite
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Interiors of Super-Earths
Valencia, Sasselov, OConnell (2006)
Ocean Planet
Earth-like
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Interiors of Super-Earths
Mass-Radius relations for 11 different mineral
compositions (Earth-like)

Valencia, OConnell, Sasselov (2005)
1ME 2ME 5ME 10ME
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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, thats what is known now)

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Interior Structure of GJ 876d
20,000
7.5 ME
DENSITY (kg/m3)
12,000
Valencia, Sasselov, OConnell (2006)
4,000
2,000
6,000
10,000
RADIUS (km)
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Interior Structure of GJ 876d
Valencia, Sasselov, OConnell (2006)
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Interior Structure of Super-Earths
Valencia, Sasselov, OConnell (2006)
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Interior Structure of Super-Earths
Kepler error bar
Valencia, Sasselov, OConnell (2006)
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Interior Structure of Super-Earths
Valencia, Sasselov, OConnell (2006)
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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
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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 KEPLERs candidates.

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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).
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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)