Jonathan Fortney University of California, Santa Cruz

1. Spectroscopy of Giant Planets Jonathan Fortney University of California, Santa Cruz PPVI Review: Madhusudhan, Knutson, Fortney, & Barman arXiv:1402.1169 JWST Transit Planets Meeting

2. We’re 40-45 years behind work in the Solar System Jupiter Gillett, Low, & Stein (1969) • CH4 dominant mid IR absorber • Temperature inversion from 7.8 mm CH4 band • Bright at 5 mm – high Tbright Lee et al. (2012)

3. The Past Ten Years of Atmospheric Characterization Line et al. (2013) • 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

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

5. Giant Planet Spectroscopy • 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?

6. Atmospheric Physics and Chemistry • 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

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

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

9. 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)

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

11. Model Atmospheres are Rounding into Shape WASP-19b Fortney Burrows WASP-19b Huitson et al. (2013) • 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 Teff range Deming Fortney

12. Fundamental Assumption • 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? Day Night HD 189733b, Dobbs-Dixon et al. (2013) HD 189733b, Showman et al. (2009)