LABORATORY SPECTROSCOPY OF RELEVANCE TO CASSINI UVIS AND ISS JOSEPH AJELLO ALEX AGUILAR RAO MANGINA PAUL JOHNSON CHARLES MALONE DAREK DZICZEK JPL H. ABGRALL MEUDON MICHAEL STEVENS NRL XIANMING LIU SET Ian Stewart Kris Larsen LASP

H2 (UVIS, ISS SATURN, JUPITER) ELECTRON IMPACT INDUCED UV & NEAR IR FLUORESCENCE LAB STUDIES (80-1200 nm) N2 (UVIS TITAN) MATCH LAB & UVIS AND ID UVIS TITAN EUV SPECTRA TRANSITION MOMENT STUDIES OF Liu et al., 2007 FOR TITAN UVIS MODELS H2 (UVIS, ISS SATURN, JUPITER) MEASURE VOIR SPECTRA (400-1000 nm) AND CROSS SECTIONS 100 eV of EF,GK,HH 1Sg+,I 1Pg ,J 1Dg  B,B’ 1Su+, C 1Pg FOR ISS PROVIDE UV CASCADE CROSS SECTION TO LYMAN & WERNER BANDS FOR UVIS 20 eV SPECTRA GIVE 3p 3Pu, 4p 3Pu – a 3Sg+, FULCHER-a , BETA BAND CROSS SECTION COMPARE TO MEUDON MODEL SO2 (ISS IO) MEASURE VOIR SPECTRA AND CROSS SECTIONS 25 AND 100 eV APPLY RESULTS TO ISS IO FILTER IMAGE INTENSITIES

UVIS EUV IMAGE ON 13 DEC2004 BRIGHT LIMB ALTITUDE DEPENDENCE AT 03h 43’ TARGET DISTANCE: 160k&16 deg phase Data(60,26,555) & records of 240” PEAK EMISSION 1100-1200 KM (hvert~1015-16 cm-2) VS PEAK PRODUCTION AT 900KM (hvert ~1018 cm-2)

LOW RESOLUTION-OPTICALLY THICK 20 eV LAB SPECTRUM WITH ID COMPARED TO UVIS TITAN 13DEC04

VOYAGER BASED* MODEL INTENSITIES AND IDENTIFICATIONS OF EUV UVIS AIRGLOW FEATURES # wavelength(A) UVIS disk rayleighs Theory (AURIC component Rayleighs-IDs)* identity+ 1 804 0.437595 2 820 0.316011 3 833 1.03374 c5(0,0),c6(0,0) 4 855 1.41705 c'(6,0),NI,c(0,0) 5 887 1.22913 c'(4,0),c'(6,2),b'(11,0),NI 6 905 0.982033 c'(3,0),c'(4,1),b'(16,2),b'(12,1) 7 916 0.969838 b'(11,1),NII 8 928 0.825229 0.7 0.2(c'64),0.2(b'91) 0.2b'(16-3),0.1(c'31) c'(3,1),c'(6,4),b'(9,1),b'(8,1) 9 945 2.13978 4.8 2.6(NI953),0.8(c'4,3),0.6(c'3,2) 0.1(b'9,2)0.1(b'16-4),0.5(c'65) c'(4,3),c'(3,2),NI,b'(16,4),b'(9,2),c'(6,5) 10 964 1.13641 4.1 2.8(NI964),0.4c'(4,4),0.2(c'66) 0.1(b'93),0.3(c'del v=0) NI,c' delta v=0) 11 983 3.26767 9.8 7.6(c'0,1),0.6(c'4,5),0.5c'(34), 0.3c'(6,7),0.3(b'94),0.1(b'16-6) c'(0,1),c'(4,5),b(1,0),c'(6,7), 12 1004 2.14150 2.4 1.0(c'0,2),0.6(b1,1),0.3(b'16-7) 0.1(b'95),0.3(c'del v=2),0.1(c'46) c'(delta v=2),b'(9,5),b(1,1) 13 1026 2.64403 H L(beta),c'(6,9),b(1,2) 14 1057 0.733667 c'(delta v=4),NI,b(1,3),b'(3,5) 15 1067-77 0.651997 NI,b'(11,8),c'(delta v=5) 16 1085. 2.94249 15.0 NII 17 1100-1110 1.02141 NI,b'(1,6),b'(9,9),b'(6,8),b'(3,7) 18 1110-1120 0.502661 b'(2,7),b'(1,7) 19 1135. 1.74414 NI 20 1148. 1.55175 NI,b'(1,8) 21 1158. 1.48184 NI,b'(0,8),b'(1,8) total(29.2R) total(36.8R) +Ajello et al.,1989;James et al., 1990 *Stevens(2001) F10.7=256(VI,II SOLAR MAX) VS F10.7=90 DEC13, 2004

HIGH RESOLUTION LAB WITH ID SPECTRUM COMPARED TO UVIS TITAN 13 DEC2004

Lab Study of Pressure Effects of the N2 EUV Spectrum by Electron Impact at 20 eV

Geissler et al., 2004

VOIR APPARATUS Vis-Optical-near IR (200-1200 nm)

CASSINI ANALYSIS WITH SO2 LABORATORY SPECTRUM CASSINI ISS FILTERS Filter Center FWHM    nm UV1     255    40 UV2     300    60 UV3     340    70 BL1     445   105 BL2     440    30 GRN     562   145 IR1 752 180 IR4 1002 200 ISS OBSERVATIONS Filter 8 eV 18 eV 98 eV ISS UV1 0.0 0.34 0.3 < 1.0 UV2 0.33 0.42 0.41 0.30 UV3 1.00 1.00 1.00 1.00 BL1 0.27 0.39 0.79 0.93 GRN 0.29 0.20 0.97 0.96

CASSINI ISS LAB STUDIES

DIRECT MEASUREMENT OF H2 GERADE STATE CASCADE CROSS SECTION TO UV RYDBERG STATES

VOIR EF-B CASCADE SPECTRUM IN CROSS SECTION UNITS

DISCREPANCY BETWEEN MODEL AND DATA FOR HIGHER LYING GERADE STATES

COMPARISON OF CROSS SECTIONS TO UNIVERSITY OF ARKANSAS GROUP

MAJOR 100 eV CROSS SECTION RESULTS IN THE VOIR TABLE 1                  e + H2  VOIR process   CROSS SECTION EXP  MODEL PREVIOUS       (10-19 cm2)      (10-19cm2)    (10-19cm2)                                                                                                                                                  total VOIR cross section  (singlets +triplets+ H-lines)…………63       - - total triplet cross section  …………………….…………………… ……..1.2               -       total ungerade    singlet  cascade cross section…………………..51    37           50*          total H lines  ................................................................. 11*** EF-state...................................................................... 20-30         ? GK+HH+IJ+................................................................ ?               Too large                                                               e+H2 UV Process                                             total UV direct +cascade ungerade states   (B+C+B'+D+...)……………………………… 460** *Dziczek et al; 2000 (UV Technique) **Jonin et al; 2000 *** Karolis and Harting;1978 and Vroom and de Heer;1969

CONCLUSIONS EARTH AND TITAN PRESENT SIMILAR EUV SPECTRA OVER 100 N AND N2 FEATURES CONTRIBUTE TO TITAN EUV CHANNEL UVIS SPECTRA EXCEPT FOR N2(c’[0,0]) BAND UVIS SPECTRUM IS WELL-MATCHED BY 20-30 eV OPTICALLY THICK LAB SPECTRA OF e + N2 e + H2 VOIR EF-B SPECTRA GERADE-UNGERADE ARE MODELED 7500-10000 A AND DISCREPANCIES 4000-7500 A HIGH LYING GERADE STATE MODELS ARE TOO STRONG(J-B,C) H2 VOIR TRIPLET STATES ARE STRONG AT 20 eV GROUND-BASED AND HUBBLE IO SO2 EMISSIONS ARE SUGGESTED AT 777,845 NM FOR OI AND 922 NM FOR SI.

OPTICALLY THICK LAB SPECTRUM AT 0. 6 AND 0 OPTICALLY THICK LAB SPECTRUM AT 0.6 AND 0.2 A FWHM COMPARED TO CASSINI 4A FWHM

GEOMETRY OF 13 DEC2004 TWO LIMB AND DISK OBSERVATIONS TARGET DISTANCE: 160k and 125k km Data(60,26,555) AND Data(60,32,555) records of 240” each Solar incidence angle=78 deg and 90 deg Target phase angle=16 deg Solar emission angle=90 deg limb Peak emission 1200 km Temp=150k , H(N2)=70 km, Nhvert (N2)=7x1015 cm-2 Number density N2=109 cm-3 CHAPMAN FACTOR=22 SLANT/VERTICAL Low Res. EUV slit =2mR (0.1deg) x 59 mR (3.6 deg)

STUDY OF FULCHER-a BANDS (d 3Pu -a 3Sg+) OF H2

TITAN EUV AIRGLOW DISK SPECTRUM