Spectroscopy of Giant Planets. Jonathan Fortney University of California, Santa Cruz. PPVI Review: Madhusudhan, Knutson, Fortney, & Barman arXiv:1402.1169. JWST Transit Planets Meeting. We ’ re 40-45 years behind work in the Solar System. Jupiter. Gillett, Low, & Stein (1969). - PowerPoint PPT Presentation
Text of Jonathan Fortney University of California, Santa Cruz
Jonathan FortneyUniversity of California, Santa CruzSpectroscopy of Giant PlanetsJWST Transit Planets MeetingPPVI Review:Madhusudhan,Knutson,Fortney, & BarmanarXiv:1402.1169
Were 40-45 years behind work in the Solar SystemLee et al. (2012)JupiterGillett, Low, & Stein (1969) CH4 dominant mid IR absorberTemperature inversion from 7.8 mm CH4 bandBright at 5 mm high Tbright
The Past Ten Years of Atmospheric CharacterizationWeve been trying very hard to make progress using instruments that were not designed for our uses
Weve gathered somewhat imprecise broadband data for dozen of planetsLine et al. (2013)
High S/N data over a broad wavelength range fundamentally changes the kinds of questions we can ask and answerLine 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 massStellar typeMigration historyDo giant planets share the abundance ratios of their parent star?Jupiter is quasi-consistent with 2-4x solarHow 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 fluxSurface gravityAtmospheric metallicityRotation rateWhat 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?ChemistryRole of deviations from equilibrium chemistryHomogenization due to vertical and or horizontal mixingAtmospheric Physics and Chemistry
Wed like to know the abundances of these molecules within a factor of ~5-10Would 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 dataPhosphorus compounds?Sulfur compounds?I dont know (thats why theyre called unknown unknowns)
Excellent Recent Progress with HST WFC3Deming et al. (2013)Kreidberg, Line, Stevenson, Bean, others, et al. (in prep)WASP-43bTransmissionEmissionAlso: Precision of ~20-30 ppm for transmission spectra: Kreidberg et al., Knutson et al.
Model Atmospheres are Rounding into ShapeFortneyBurrowsWASP-19bHuitson et al. (2013)DemingFortneyWASP-19b A major concern of mine over the past 5 years has been the lack of comparisons between modeling groupsThis 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
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 189733b, Showman et al. (2009)HD 189733b, Dobbs-Dixon et al. (2013)DayNightFundamental Assumption