UVIS Saturn EUVFUV Data Analysis * 07/16/96 UVIS Saturn EUVFUV Data Analysis R. West and D. Tice *

Nine EUVFUV sets Row -> Integration number -> * 07/16/96 Nine EUVFUV sets Row -> Integration number -> Flat field corrections Residual vertical striping is apparent *

Data Reduction Cube Generator (includes flat field) * 07/16/96 Data Reduction Cube Generator (includes flat field) Image geometry is a product Divide by a solar spectrum processed by D. Shemansky’s simulator software to get I/F There is a slope issue here. Subtract a background from off-planet pixels Extract data in a latitude band and fit to Minneart function to improve signal/noise *

Selection of Pixels in a Latitude Band -30+-10 Deg.

* 07/16/96 Minneart Fit *

Geometry Corrections Identify four edges of planet based on geometry Pixels with valid longitude values are assumed to be ‘on-planet’ Identify four edges of planet based on I/F values. Points are assumed ‘on-planet’ where either condition is met: high signal to noise ratio (for 1600-1900 Ang. composite image) low signal to noise ratio (within the Lyman-Alpha band)

Sample of Results: 022SA_2006_075 021SA_2006_063

Model 1600-1900 Å Multiple Scattering radiative transfer, including polarization Rayleigh scattering by molecular H2 and He Absorption and scattering by aerosols Absorption by (mainly) C2H2, PH3, other hydrocarbons Gas profiles from Moses et al. (2000) and Prange et al. 2005

Relevant Absorbers (from Prangé et al., 2005)

Profiles from Moses et al., 2000

Sample Fits Model 42 Example

Low Phase, Center/Limb Behavior Strong center/limb differences not matched by model. Model acetylene features have smaller amplitude than observed. Slope between 1600 and 1700 Angstroms not well matched

Center-To-Limb Behavior

Phase Angle Dependence Relatively good fit to high phase and to limb at low phase but not to central meridian at low phase suggests acetylene profile needs to decrease at depth but not at high altitude. Not obvious this will fix the problem. No evidence for high altitude aerosol scattering. Need to deconvolve in the spatial domain?

Status Report on Saturn Models Continuing to add new data sets – will lead to better coverage of the northern hemisphere. These data provide [too] many constraints on the models – (absolute I/F spectra from 160-190 nm, limb-darkening at all wavelengths, phase behavior). A successful solution to all these has yet to be found. Large difference (from other observations/models) implied for C2H4 and possibly for deep C2H2. Residual questions about calibration/method (including temperature dependence of absorption coefficients) and need to deconvolve must be addressed.

Backup Material

Prangé et al. Data and Model Our calculation Prangé paper

CIRS Results Fouchet presentation

References Moses, J. et al., ‘Photochemistry of Saturn’s Atmosphere I. Hydrocarbon Chemistry and Comparisons with ISO Observations’, Icarus 143, 244–298 (2000) Prangé, R. et al., ‘Latitudinal variation of Saturn photochemistry deduced from spatially-resolved ultraviolet spectra’, Icarus 180, 379-393 (2005).

UVIS Extended Mission – Saturn and Titan Solar Occultations Stellar Occultations Auroral Mapping (Wayne Pryor) Other mapping (EUVFUV) for hydrocarbon chemistry

Saturn and Titan Solar Occultations

Saturn – Solar Occultations Fro Don Shemansky

Saturn Stellar Occs in the XM Rev 87 Alp Cru Latitude -19 Rev 97 Alp Cru Latitude +1.3 Rev 97 Bet Cen Latitude +19 Full table..\..\Desktop\Folders and files\PF6h9 Occultations

Titan Stellar Occs in the XM Chronological order Sorted by latitude

Titan EUVFUV in XM T Phase rev C/A +5 or -5 hours 62 11.1 119 +5 Most are 7 hr. duration (2-9 hr. from C/A) 69 30.4 132 +5 56 45.6 112 +5 54 63.2 110 +5 46 95.8 91 +5 50 106.2 102 +5 Template P 48 107.0 95 +5 66 133.4 125 -5 57 138.4 113 -5 58 146.7 114 -5 60 163.1 116 -5* Ends at -5 to accommodate Radar (template P) 62 166.4 119 -5

Extended Mission – Saturn and Titan Solar Occultations Saturn Working Group Presentation by Scott Edgington