Planetary Sizes

Dimitar Sasselov

Harvard-SmithsonianCenter for Astrophysics

Some of the Hot Jupiters do not match wellmodels based onJupiter & Saturn:

More diversity than expected ?...

Gaudi (2005) w Bodenheimer et al.(2003),Laughlin et al. (2005) models

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

Talk Plan

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

Photometry of Extrasolar Planets

Mass-Radius diagram:

Kon

acki

, Tor

res,

Sas

selo

v, J

ha (

2005

)

All knowntransitingextra-solarplanets

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

The Measurement Errors:

OGLE-TR-113b

Transit Light Curve

Radial Velocities

OGLE: Udalski et al. (2003)

P = 1.43 daysI = 14.4 mag

Stellar Mass and Age:Stellar evolution track for 3 metallicities and Helium content:

Stars evolvefrom bottomzero-age mainsequence

HD 209458

Our Sun

Lines of constantstellar radii

Cody & Sasselov(2002)

Age = 7 Gyrs

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

The Measurement Errors:

OGLE-TR-10b

Transit Light Curve

Radial VelocitiesKonacki, Torres,Sasselov, Jha (2005),

green & brown points:Bouchy, Pont, Melo,Santos, Mayor, Queolz & Udry (2004)

OGLE: Udalski et al. (2002)

P = 3.10 daysV = 14.9 mag

Improved photometry:H

olm

an (

2004

)

Magellantelescope

Improved photometry:

Mou

tou,

Pon

t, B

ouch

y, M

ayor

(20

04)

VLTtelescope

OGLE-TR-132b

OriginalOGLElight curve

Improved photometry:

Charbonneau, Brown, Gilliland, Noyes (2004)

Hubble SpaceTelescope -STIS

HD 209458b

Wavelength-dependentlimb darkeningallows moreaccurate RP andRS determination

Mass-Radius diagram:

Kon

acki

, Tor

res,

Sas

selo

v, J

ha (

2005

)

Models ofthe interior:

• Overall Z;• Core vs. no-core;• Age.

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)

Interiors of Giant Planets

Phase diagram (hydrogen):G

uill

ot (

2005

)

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)

Interiors of Giant Planets

Jupiter’s core mass and mass of heavyelements:

Interiors of Giant Planets

Saumon &Guillot (2004)

The heavyelements aremixed in theH/He envelope

Saturn’s core mass and mass of heavyelements:

Interiors of Giant Planets

Saumon &Guillot (2004)

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

Interiors of Giant Planets

Some of the Hot Jupiters seem to havetoo large, ortoo small, sizes:

More diversity than expected ?...

Gaudi (2005) w Bodenheimer et al.(2003),Laughlin et al. (2005) models

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)

Interiors of Hot Jupiters

Core-less Very Hot Jupiters could lose alltheir mass, if parked so close early…

Interiors of Hot Jupiters

DS (2003) w updates

They could also capturehigh-Z planetesimals ?

OGLE-TR-56b has:Vorb = 202 km/sec,Vesc = 38 km/sec.

Very Hot Jupiters

Dayside thermal emission:

Seager et al. (2005)

Atmosphericmodels for thetwo transiting HotJupiters: TrES-1 & HD209458b.

Best fits for both CO and H2O seem to need high C/O values.

Super-Earths (1-10 Mearth)

Are they there ?

What is their Mass-Radius relation(s)

Detection Doppler shifts

Transits

Interiors of Super-Earths

Formation and survival of largeterrestrial planets:

Interiors of Super-Earths

Ida & Lin (2004)

All evidenceis that theyshould bearound:

The models follow the techniques andmany assumptions of Earth’s model:

Interiors of Super-Earths

Valencia, O’Connell, Sasselov (2005)

The mantle is taken to beconvecting as a single layer.

Schematic temperature profile

Mass-Radius relations for 11 differentmineral compositions:

Interiors of Super-Earths

Valencia, O’Connell, Sasselov (2005) 1ME 2ME 5ME 10ME

The Earth is the only planet model thathas a liquid outer core:

Interiors of Super-Earths

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