Jonathan Fortney University of California, Santa Cruz Spectroscopy of Giant Planets JWST Transit Planets Meeting PPVI Review: Madhusudhan, Knutson, Fortney, & Barman arXiv:

We’re years behind work in the Solar System Lee et al. (2012) Jupiter Gillett, Low, & Stein (1969) CH 4 dominant mid IR absorber Temperature inversion from 7.8  m CH 4 band Bright at 5  m – high T bright

The Past Ten Years of Atmospheric Characterization We’ve been trying very hard to make progress using instruments that were not designed for our uses We’ve gathered somewhat imprecise broadband data for dozen of planets Line et al. (2013)

High S/N data over a broad wavelength range fundamentally changes the kinds of questions we can ask and answer Line et al. (2013)

 We are not merely tying up loose ends – it is not even close to that!  Is atmospheric metal-enrichment a hallmark of giant planets?  How does this change with:  Planet mass  Stellar type  Migration history  Do giant planets share the abundance ratios of their parent star?  Jupiter is quasi-consistent with 2-4x solar  How important is disk condensation (snow lines) in leading to deviations in abundances? Giant Planet Spectroscopy

 How significantly do atmospheres deviate from radiative equilibrium (energy sources and sinks)  How is day-night temperature homogenization affected by:  Incident flux  Surface gravity  Atmospheric metallicity  Rotation rate  What is the role of cloud opacity?  Does it effect emitted spectra as well as transit spectra?  Can we figure out what the cloud compositions are?  Chemistry  Role of deviations from equilibrium chemistry  Homogenization due to vertical and or horizontal mixing Atmospheric Physics and Chemistry

We’d like to know the abundances of these molecules within a factor of ~5-10 Would allow connection to planet formation Shabram et al. (2011) Broad JWST coverage over molecules of interest

Shabram et al. (2011) Broad JWST coverage over molecules of interest from a C/O ratio or photochemical perspective

The Unknown Unknowns: Our imperfect understanding of these atmospheres, in the absence of spectral data Phosphorus compounds? Sulfur compounds? I don’t know (that’s why they’re called unknown unknowns)

Excellent Recent Progress with HST WFC3 Deming et al. (2013) Kreidberg, Line, Stevenson, Bean, others, et al. (in prep) WASP-43b TransmissionEmission Also: Precision of ~20-30 ppm for transmission spectra: Kreidberg et al., Knutson et al.

Model Atmospheres are Rounding into Shape Fortney Burrows WASP-19b Huitson et al. (2013) Deming Fortney WASP-19b  A major concern of mine over the past 5 years has been the lack of comparisons between modeling groups  This is still imperfect but has gotten a lot better  Some groups have honed their R-T, chemistry, and clouds on brown dwarf spectra across a wide T eff range

1D techniques, including retrieval techniques, aim to understand hemispheric average conditions Patchy clouds on planets may be a problem? Non uniform transiting planet day sides may be a bigger problem? HD b, Showman et al. (2009) HD b, Dobbs-Dixon et al. (2013) Day Night Fundamental Assumption