Variability in Titan’s Nitrogen Emissions (plus a little about the ~1600Å mystery feature)

From January Team Meeting Nitrogen Day/Night results Dayside atomic Nitrogen: 0.033 ± 0.015 kR Nightside Atomic Nitrogen: 0.027 ± 0.008 kR Dayside Nitrogen LBH: 0.017 ± 0.024 kR Nightside Nitrogen LBH: 0.012 ± 0.007 kR Little to no day to nightside correlation (R2 < 0.3)

Total Titan Spectrum from T-14

Full spatial/spectral res. Data Set Selection Full Disk Observation Day + Nightside Full spatial/spectral res. T-05: 2005_04_16_11_23_11 T-09: 2005_12_26_21_45_00 T-10: 2006_01_15_14_47_37 T-11: 2006_02_27_13_30_58 T-13: 2006_05_01_02_23_53 T-14: 2006_05_01_02_23_53 T-15: 2006_07_02_11_57_46 T-17: 2006_09_07_12_52_22 T-18: 2006_09_23_11_34_29 T-21: 2006_12_12_04_17_34 T-24: 2007_01_28_22_35_38 T-27: 2007_03_26_03_30_00 T-31: 2007_05_28_10_01_42 T-34: 2007_07_18_16_28_23

1.2 ± 0.3e-3 6.3 ± 1.7e-4 1.3 ± 0.5e-3 5.2 ± 1.2e-4 TIMED-SEE total variability

Jacques stellar data and compositional fits C2H2 C2H4 C4H2 Tholin

Day vs. Nightside Disk Spectra T-27 Example Fit Day vs. Nightside Disk Spectra Dayside Nightside

T-27 Input Spectra TIMED-SEE Atomic N Molecular N2 H Lyman-alpha CH4 Absorption

T-27 Example Dayside disk model fit. 0.012 kR Atomic N 0.025 kR Molecular N 0.314 kR Lyman-alpha 1.510 kR Reflected Solar

Total Disk Rayleighs 0.99±.39 kR 0.12±.03 kR Dayside/Nightside Correlation: R2=0.42 Dayside/Sun Correlation: R2=0.11 Nightside/Sun Correlation: R2 = 0.001

Atomic N Brightness Dayside/Nightside Correlation: R2=0.03 Dayside/Sun Correlation: R2=0.04 Nightside/Sun Correlation: R2 = 0.005

Molecular LBH Dayside/Nightside Correlation: R2=0.01 Dayside/Sun Correlation: R2=0.03 Nightside/Sun Correlation: R2 = 0.002

Conclusions Wide dayside disk brightness correlated with Solar spectrum. Variation in Nightside brightness uncorrelated with incident Solar spectrum. Total atomic and molecular nitrogen emissions uncorrelated with solar input or orbital position of Titan. Emission due to precipitating magnetospheric electrons as important as photoelectrons.

REALLY STRONG ~1600A FEATURE; T27 ~1600Å line present in solar spectrum, but unmodeled by Titan hydrocarbons.

WEAK/NON 1600A FEATURE Non-existent ~1600Å feature in either Solar or Titan Disk Spectrum