Titan Airglow: FUV & EUV 2009 UVIS
Spectra of Airglow During Day,
Night & Eclipse :
JOSEPH AJELLO
JPL
MICHAEL STEVENS
NRL
ROBERT WEST
JPL
JACQUES GUSTIN
LPAP
GREG HOLSCLAW
CU
TODD BRADLEY
UCF
TITAN PROTON PLASMA (0.1 keV-4 MeV)
& SOLAR XUV GENERATES 2-level
IONOSPHERE (300-1500 KM)
S. PolSS. POLE
South
shelf
-Solar XUV Excitation –Strong
Top Ionosphere
-Magnetospheric: p and O+
Plasma Sporadic low
ionosphere (Cravens et al.,
2008).
N2 Cross section Analysis for Dayglow
VI (2)→UVIS (16)→Lab(e +N2 300 features)
V(z)=g(z) x w AURIC MODEL
gj (z) = F (e) x n(z) x s(e)
Dl=0.2Å
Dl=30Å
Dl=5Å
DD
ISS & UVIS OBSERVATION OF
TITAN SOLAR ECLIPSE @ 600K km
UV- VIS-near
IR (200-1200)
nm N2 night
glow to 1000
km
plasma + N2
FUV T53 DARK SIDE RECORD 0 LIMB &
DISK SPECTRA DOY110-2009 @15K km
(MRH = SURFACE-800 KM)
polar
T53 EUV DARK SIDE RECORD 1
LIMB & DISK SPECTRA
DOY110-2009 @15K km
-Spectrum =Eclipse at 20 x closer
-4-minute records
-Record 0 MRH = surface to 800
km
-Record 1;MRH = 800-1100 KM)
-NO Rayleigh scattering
Plasma excitation : 500-1200 km
-Molecular bands and NI ,II lines
-1/10 Intensity of Dayglow
Laboratory Result: p + N2
ELECTRON CROSS SECTIONS FOR
TITAN DAYGLOW UV EMISSION
MODEL
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sLBH=0.7
A&S (1985)
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STEVENS ET AL., 2011
“Production of Titan’s Far ions
Ultraviolet Nitrogen Airglow”
AURIC Code Emission Cross
Sections:
N2 Carroll-Yoshino c4′—X
system,b‘-X, b-X systems
N I and N II multiplets
the N2 Lyman-Birge-Hopfield a—X
system (Young et al., 2010)
the N2 Vegard-Kaplan A—X bands
Best (S/N) Titan Dayglow UVIS
Limb Spectrum; 22June 2009: ‘800
km STARE’ Stevens et al., 2011
–40
DEC (deg)
–42
EUV
–44
–46
–48
4
2
0
RA (deg)
–2
–4
1500
Pixel Center Ray Height (km)
One hour
EUV and
FUV image
of 15 – 4
minute
records .
1000
FUV
500
0
0
10
20
30
40
Pixel Number
50
60
AURIC MODEL FIT TO UVIS EUV
SPECTRUM AT 1000 KM
AURIC MODEL FIT TO UVIS FUV
SPECTRUM AT 1000 KM
AURIC MODEL OF FUV VERs AND
COLUMN EMISSION RATES
The FUV Dayglow Limb Spectra
of Titan Tb Tangential Scan
Surface to Exosphere: 13Dec04.
DARK SIDE OBSERVATION OF TITAN ON
25MARCH2008
FUV LIMB PROFILE INTENSITIES
OF 25 MARCH2009
Model fit to UVIS Dark Limb (Twilight)
EUV Spectrum from 25Mar08 with a
Regression Model - 7-Vectors)
HOW to GET a BRIGHT UV Airglow
in 2009

BRIGHTEST LIMB
AIRGLOW 22JUNE
2009 obs[14]
SZA=53DEG, MRH =1000
km S/C ~60k KM
BRIGHTEST DISK & 2ND
LIMB 12OCT OBS[4551]
LIMB~ 1000KM
SZA~95, S/C ~175k KM

2009 Observations from Lower
Ionosphere Dark Limb (F0,F5) to
Topside Bright Limb (F9, F14, F48)
SUMMARY OF 2009 ECLIPSE, LIMB,
BRIGHT DISK AND DARK DISK
UVIS OBSERVATIONS OF TITAN
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Solar Driven processes on Dayside and Twilight
Observed EUV and FUV Emissions during 1 of 3
Eclipses. Probably Plasma impact.
Tentative Sporadic FUV Nightglow Spectra at 0.1
Intensity level of dayglow (500-1200 km). Probably
Plasma Impact (protons, O+, electrons).
Twilight (Terminator) Glow-Solar XUV at 90-120
deg Limb SZA ~ 0.2-0.5 Dayside Intensity.
N2 EUV (12R) /FUV (200R) dayglow structure
similar to Earth
Extend Published/Modeled spectra from 800-1900 Å
Elvis Lives (Titan Organic
Chemistry-Biomarker! )
45 years with my Honey