“Theory for Giant Exoplanets: A Potpourri” A.Burrows Dept. of Astrophysical Sciences Princeton University With collaborators D. Spiegel, I. Hubeny, N. Madhusudhan, K. Heng, J. Budaj, … A.Burrows Dept. of Astrophysical Sciences Princeton University With collaborators D. Spiegel, I. Hubeny, N. Madhusudhan, K. Heng, J. Budaj, …

Outline  Transits of Giant planets (EGPs): R p vs. M (and Brown Dwarf R p vs. M)  The “Deuterium Burning” Limit  Wavelength-Dependence of Transit Radius  “Hot Jupiter” Secondary Eclipse Spectra Temperature-Pressure Profiles  Optical Albedos  Photometric Light Curves  Variation of Spectra with Planetary Phase  Planet thermal, composition, brightness Maps  High-Contrast Imaging (wide-separation)  Distinguishing the Modes of Giant Planet Formation  Transits of Giant planets (EGPs): R p vs. M (and Brown Dwarf R p vs. M)  The “Deuterium Burning” Limit  Wavelength-Dependence of Transit Radius  “Hot Jupiter” Secondary Eclipse Spectra Temperature-Pressure Profiles  Optical Albedos  Photometric Light Curves  Variation of Spectra with Planetary Phase  Planet thermal, composition, brightness Maps  High-Contrast Imaging (wide-separation)  Distinguishing the Modes of Giant Planet Formation

Radius-Mass Relationship for Irradiated EGPs (“Hot Jupiters”) (dependence on age, star, semi-major axis distance, planet mass, “core mass,” atmospheric opacities)

Radius “anomalies”: Some are “small” and some are “large” Spread in R p (in Optical and IR): Transit Radius vs. Planet Mass HD GJ 436b WASP-12b TrES-4

Larger EGPs: Models vs. Data Higher Opacity/Metallicity Atmospheres increase radii

Smaller EGPs: Models vs. Data Radius Deficits: Need “ice/rock” cores?

Approximate “Core” Mass vs. Stellar Metallicity Burrows et al Note measurement of HAT-P-1b HAT-P-14b HAT-P-3b See also Guillot et al. 2006

Core Entropy vs. Radius for Transiting Planets Spiegel & Burrows 2011

Effects of Extra Core Heating on EGP Radii

Large Radiative Zone, slowly moving inward Irradiated Atmosphere of HD209458b  ~ 10 6 Outside Unchanged Irradiation inhibits flow of Heat from the Core

Spiegel & Burrows 2011 Day- and night-side cooling done consistently

T/P Profiles as a Function of Joule Heating Spiegel & Burrows 2011 Guillot & Showman 2002 hypothesis? Yes

Radius Evolution with Heating in the Radiative Zone Spiegel & Burrows 2011

Core Cooling versus Core Heating: No Instability Spiegel & Burrows 2011 No radius instability due to B-fields

Brown dwarf Radii (when we know the Mass and have an estimate of the age (?)- ambiguous interpretations Burrows et al. 2011

Brown dwarf Radii - functions of metallicity, clouds, …: 5- 30% Brown dwarf Radii - Not just a test of the EOS! Burrows et al. 2011

Deuterium-Burning Mass Spiegel, Burrows, and Milsom 2011

Evolution Burrows et al Planets Brown Dwarfs? Stars

What is meant by “deuterium burning”? Changing the “deuterium- burning criterion” from 10% to 50%, and also from 50% to 90% changes the required mass by nearly 1 M J ! More helium, more deuterium, and higher opacity result in lower D- burning mass. Roughly 13 M J, but model-dependent. Spiegel, Burrows, Milsom 2011

Wavelength-Dependence of the Transit Radius “Transmission Spectroscopy”

With upper- atmosphere optical absorber Graphics by D. Spiegel Transit chord

Na detection: Charbonneau et al HD209458b: Na-D Radius is Larger in Na-D!

Fortney et al Transit Radius vs. Wavelength aka. “transmission spectroscopy”?

Burrows, Rauscher, Spiegel, & Menou 2010 Fractional Atmosphere vs. Wavelength

HD b: Transit Radius vs. Wavelength Burrows, Rauscher, Spiegel, & Menou 2010 see also Fortney et al. 2010

HD b: Transit Radius vs. Wavelength - Measuring Orbit and Wind Speeds? Using Burrows, Rauscher, Spiegel, & Menou 2010 Ingress vs. Egress

“Hot Jupiter” Spectra and Temperature-Pressure Profiles Secondary Eclipses Thermal Inversions?

Burrows, Budaj, & Hubeny 2008 IRAC 1 > IRAC 2 !

Mostly H 2 O

Water ? CO JWST!! CH 4 ?

Hot Upper Atmospheres and Inversions

Heated upper atmosphere! IRAC 1 < IRAC 2 !

Strong Absorber at Altitude (in the Optical) Thermal Inversions: Water (etc.) in Emission (!) Hubeny, Burrows, & Sudarsky 2003 Burrows et al OGLE-Tr-56b Toy Model assumed TiO w. Inversion w/o Inversion

Probing Structure During Secondary Eclipse Comparing theoretical models with data (particularly Spitzer, but increasingly ground-based too) allows us to place constraints on composition and atmospheric structure and dynamics. 1-D Approaches: Thermochemical equilibrium (Burrows, Fortney, Barman) Observed (low-res) spectrum! Spiegel, Silverio, & Burrows 2009

Burrows et al Water in Emission! IRAC 1 < IRAC 2 ! ! H 2 O

Indices of Upper-Atmosphere Heating and Inversion:  Inversion: IRAC 2/IRAC1 - High “Bump” at IRAC3 (water in emission?) - “other” emission features  Hot Upper Atmosphere: “High” planet-star flux ratios in IRAC 2, IRAC 3, and IRAC 4 bands (and at 24 microns?)  Hot Spot advection??  What is absorbing in the optical at altitude?  Inversion: IRAC 2/IRAC1 - High “Bump” at IRAC3 (water in emission?) - “other” emission features  Hot Upper Atmosphere: “High” planet-star flux ratios in IRAC 2, IRAC 3, and IRAC 4 bands (and at 24 microns?)  Hot Spot advection??  What is absorbing in the optical at altitude?

Spiegel, Silverio, & Burrows 2009

TiO/VO cross sections Solar abundance TiO (at limb) inconsistent with transit observations! Désert et al. 2008

Can gas-phase TiO explain temperature inversions? Figure from Fortney et al. (2008) As described in Hubeny et al. (2003), Burrows et al. (2007, 2008), and Fortney et al. (2008) One alternative: sulfur photochemistry (Zahnle et al. 2009) Inversion No Inversion Problem: inversions do not appear to correlate with temperature

Cause of Heating in Upper Atmosphere? FExtra absorber in the Optical at Altitude (low pressures)? FCan it be TiO/VO (Hubeny et al. 2003; Burrows et al. 2008; Fortney et al. 2008)? FSulfur chemistry and photolysis: Thiozone (S 3 ), allotropes of S, HS (Zahnle et al. 2009) - metallicity dependence (XO-2b)? FOnly weakly correlated with stellar insolation (e.g., XO- 1b and HD b!) - no simple parametrization! FWave heating?? FC/O > 1 (?) (Madhusudhan et al.); but need hot upper atmospheres FTheory: Need non-equilibrium chemistry & 3D GCM to resolve? FObservation: Need better and more definitive optical spectra FExtra absorber in the Optical at Altitude (low pressures)? FCan it be TiO/VO (Hubeny et al. 2003; Burrows et al. 2008; Fortney et al. 2008)? FSulfur chemistry and photolysis: Thiozone (S 3 ), allotropes of S, HS (Zahnle et al. 2009) - metallicity dependence (XO-2b)? FOnly weakly correlated with stellar insolation (e.g., XO- 1b and HD b!) - no simple parametrization! FWave heating?? FC/O > 1 (?) (Madhusudhan et al.); but need hot upper atmospheres FTheory: Need non-equilibrium chemistry & 3D GCM to resolve? FObservation: Need better and more definitive optical spectra -“Can’t” be at equilibrium abundances (Fortney et al.): cold trap (condenses out), day-night circulation sink; Heavies settle; Needs vigorous vertical mixing to work (Spiegel et al. 2009!) - problematic? - Desart et al. (?): < ~ solar (HD b)

Secondary Eclipses in the Optical: MOST, Kepler, and CoRoT “Albedos”

Close-in EGPs

MOST HD b Albedo: Burrows, Ibgui, & Hubeny 2008 !! Rowe et al. 2007

CoRoT-1b(Optical and K band): Rogers et al. 2009

CoRoT-2b(Optical and IRAC): Snellen et al. 2009

Spiegel & Burrows 2010

Planetary Light Curves and Spectral Variation with Phase (Close-in) (Photometric Variations)

Burrows, Rauscher, Spiegel, & Menou 2010 Planet/Star Flux Ratio vs. Wavelength and Phase

J-band HD b Map (model a03) Burrows et al. 2010

IRAC3 band HD b Map (model a03)

I band HD b Map (model a03)

HD b: Integrated Phase Light Curves: With inversion/hot upper atmosphere Burrows, Rauscher, Spiegel, & Menou 2010  -dependent Trough/peak shifts

HD b: Integrated Phase Light Curves: No upper atmosphere absorber Burrows, Rauscher, Spiegel, & Menou 2010  -dependent Trough/peak shifts

Remote Sensing of Exoplanets (Direct Detection and Imaging of planetary systems)

Fomalhaut b Kalas et al. 2008; < 3 M J a ~ 115 AU !!

HR 8799bcd(e) Marois et al M b ~ 7 M J M c ~10 M J M d ~10 M J D = 24, 38, 68 AU

HR 8799b Madhusudhan, Burrows, & Currie 2011 Very Dusty Atmospheres - low gravity? See also Barman et al.; non- equilibrium chemistry?

Spectroscopic and Photometric Discriminants of Giant Planet Formation Scenaros D. Spiegel and A. Burrows 2011

JWST?

 What limits super-rotational atmospheric flows?  Day/Night Contrasts?  What is the “extra absorber” in many hot-EGP atmospheres?  Why are some “Hot Jupiters” so large (R p vs. M p )?  Is there a dynamical, structural, and/or thermal role for B-fields?  What condensates reside in planetary atmospheres?  Winds and Evaporation?  Tidal Effects?  Atmospheric, Envelope, and Core compositions?  Mode(s) of Formation (and Signatures!)? Theoretical Questions

Graphic by D. Spiegel