Laboratory Studies on the Irradiation of Solid Ethane Analog Ices and Implications to Titan s Chemistry

Laboratory Studies on the Irradiation of Solid Ethane Analog Ices and Implications to Titan s Chemistry 5th Titan Workshop at Kauai, Hawaii April 11-14, 2011 Seol Kim

Outer Solar System Model Ices with Ionizing Radiation Model Ices to investigate: Ethane ( H 6 in different morphology and temperatures Ammonia (NH 3 and methane (CH 4 ice system Ammonia (NH 3 and C n H 2n+2 (n = 1-6 ice system (a Radioylsis-induced products (b Production rates and yields (c Astrophysical implications (radiative transfer (1 Kim et al. ApJ 711, 744 (2010 (2 Kim & Kaiser ApJ 729, 68 (2011

Outer Solar System Model Ices with Ionizing Radiation Model Ices to investigate: Ethane ( H 6 in different morphology and temperatures Ammonia (NH 3 and methane (CH 4 ice system Ammonia (NH 3 and C n H 2n+2 (n = 1-6 ice system (a Radioylsis-induced products (b Production rates and yields (c Astrophysical implications (radiative transfer (1 Kim et al. ApJ 711, 744 (2010 (2 Kim & Kaiser ApJ 729, 68 (2011

Radiolysis-Driven Processing of Saturn s Satellites Enceladus Titan Cooper et al. Planet. Space. Sci. (2009 Lorenz et al. Geophys. Res. Lett. (2008

Laboratory Simulation: GCR-Induced Secondary Electrons 100 na, 1 hr: Fluence of 5.5 10 14 electrons cm -2

Electron Trajectories and Energy Loss: CASINO Code 0.40 0.35 0.30 Probability 0.25 0.20 0.15 0.10 0.05 0.00 4.0 4.2 4.4 4.6 4.8 5.0 Tranmitted Energy (kev NH 3 C n H 2n+2 (n = 1 6 Ices E trans (5 kev: 4.53 kev Linear Energy Transfer: 470 ev/129 nm or 3.6 kev/µm Radiation Dose: 3.8 ev molecule -1 (20 min, 1 µa http://www.gel.usherbrooke.ca/casino/what.html

Infrared Spectra of Ethane ( H 6 Ice at 10 K Wavelength (µm 2 2.5 5 10 1520 Wavelength (µm 2 5 10 1520 0.5 ν 10 0.5 0.4 0.4 Absorbance 0.3 0.2 ν 5 ν 8 +ν 11 Absorbance 0.3 0.2 0.1 ν 11 ν 12 0.1 ν 6 0.0 ν 2 +ν 6 0.0 5000 4500 4000 3500 3000 2500 2000 1500 1000 500 5000 4500 4000 3500 3000 2500 2000 1500 1000 500 Wavenumber (cm -1 Wavenumber (cm -1 Thermally Amorphous Crystalline II Radiolytically

Phase Reversibility of Solid Ethane ( H 6 Thermally Wavelength (µm 6.3 8 10 12 14 0.20 Radiolytically Wavelength (µm 6.3 8 10 12 14 0.14 0.18 0.16 0.12 0.14 0.10 Absorbance 0.12 0.10 0.08 0.06 27 K 28 K Absorbance 0.08 0.06 0.04 after Irradiation at 30 K 0.04 0.02 0.02 29K 0.00 1600 1400 1200 1000 800 700 Wavenumber (cm -1 Before Irradiation at 30 K 0.00 1600 1400 1200 1000 800 700 Wavenumber (cm -1

Flux-Dependent Product Formation at 10 K 0.012 Wavelength (µm 3.0 3.1 3.2 3.3 ν 3 ( H 2 ν 3 (CH 4 0.030 Wavelength (µm 5.9 7.5 10.0 15.0 20.0 0.010 ν 9 ( H 4 0.025 H 4 Absorbance 0.008 0.006 0.004 100 na 20 na ν 10 ( H 5 Absorbance 0.020 0.015 0.010 100 na H 8 CH4 H 8 H 8 H 4 H 2 H 5 0.002 0.000 0 na 0.005 20 na 0.000 0 na 3350 3300 3250 3200 3150 3100 3050 3000 Wavenumber (cm -1 1700 1600 1400 1200 1000 800 600 500 Wavenumber (cm -1 Major Products: Ethylene( H 4 and Butane ( Others: Ethyl Radical ( H 5, Acetylene ( H 2, Methane (CH 4, and Butene ( H 8

Ion Current Profiles during Warm-Up Phases Ethane (m/z=30 Blank 100 na Emission Currents (a 10 20 40 60 80 100 120 140 160 170 1E-7 (b 10 20 40 60 80 100 120 140 160 170 1E-7 1E-8 m/z = 30 1E-8 m/z = 30 1E-9 1E-9 Current (A 1E-10 1E-11 Current (A 1E-10 1E-11 1E-12 m/z = 16 1E-12 m/z = 16 1E-13 1E-13 m/z = 58 10 20 40 60 80 100 120 140 160 170 Temperature (K Fragment due to EI ionization 10 20 40 60 80 100 120 140 160 170 Temperature (K Product ion currents of methane (CH 4+ and butane ( + monitored

Temperature and Phase-dependent Yield CH 4 Temperature, K Amorphous 10 Crystalline 10 Crystalline 30 Crystalline 50 (1.5±0.2E15 (1.5±0.2E15 (1.4±0.3E15 (1.4±0.3E15 Solid Phase IR Column Density, molecule cm -2 Normalized, % 100 100 93 73 Ion Charge, C (13.0±0.3E-10 (12.1±0.3E-10 (11.1±0.3E-10 (9.7±0.3E-10 Gas Phase QMS Normalized, % 100 93 85 75 Amorphous 10 (9.9±1.4E15 100 (5.8±0.0E-10 100 Crystalline 10 (9.2±1.7E15 93 (4.1±0.0E-10 71 Crystalline 30 (7.6±1.4E15 77 (3.5±0.3E-10 60 Crystalline 50 (6.3±1.1E15 64 (4.0±0.3E-10 69 (Fluence of 5.5 10 14 electrons cm -2 impinging on (1.3±0.1E17 molecules cm -2

+ + + + + + + 0 Kinetic Model and Column Density Fits H 6 column density, cm -2 1.45E+017 1.40E+017 1.30E+017 1.20E+017 1.10E+017 H 6 10 K H 6 10 K H 6 30 K H 6 50 K 1.00E+017 CH 4 CH 2 9.00E+016 3.00E+015 2.50E+015 H 5 H 5 H 5 H 5 k 2 k 4 H 6 k 3 H 5 column density, cm -2 2.00E+015 1.50E+015 1.00E+015 5.00E+014 k 1 0.00E+000 0 1.00E+016 H 4 H 4 H 4 H 4 H 2 k 12 k 6 H 5 k 5 H k 7 H 2 column density, cm -2 8.00E+015 6.00E+015 4.00E+015 2.00E+015 0.00E+000 0 H 2 H 8 H 4 H/H 2 k 8 H 4 column density, cm -2 6.00E+014 4.00E+014 2.00E+014 H 2 H 2 H 2 H 2 7.00E+014 H 3 H k 10 0.00E+000 0 1.60E+015 CH 4 CH 4 CH 4 CH 4 k 9 H 2 H/H 2 CH 4 column density, cm -2 1.20E+015 8.00E+014 4.00E+014 0.00E+000 X k 11 column density, cm -2 8.00E+015 6.00E+015 4.00E+015 2.00E+015 0 1.00E+016 0.00E+000 0 H + H 6 k 13 C2 H 5 + H 2 H 8 column density, cm -2 1.20E+015 8.00E+014 4.00E+014 H 8 H 8 H 8 H 8 1.40E+015 0.00E+000 0 Kim et al. ApJ 711, 744 (2010 time, minutes time, minutes time, minutes time, minutes

Energy Deposition of Titan Surface (ev cm -2 sec -1 4E-8 1E-8 solar min solar max Ground Level Scalar Muons (cm 2 sec MeV -1 1E-9 1E-10 1E-11 1E-12 1E-13 1E-14 π Φ = 2π 0 d(cosθ ψ ( Θ Φ( E Ed( E 0 1E-15 0.01 0.1 1 10 100 1000 10000 Energy (GeV/Muon Lorenz et al. (2008 Energy flux (MeV cm -2 sec -1 Particle Solar minimum Solar maximum Muon+ 26.1 26.0 Muon- 19.8 19.7 Gamma-ray 0.0068 0.0068 Keran O Brien - NAU

Radiative Transfer to Titan Surface: Methane (CH 4 and Butane ( Production Rates Laboratory: 1.8 10 17 ev cm -2 2E16 2E16 1/125 yrs 1E16 1E16 Column Density (cm -2 Titan Surface: 46 MeV cm -2 s -1 CH 4 Butane ( : 7.9 10-20 kg cm -2 s -1 1E15 5E14 1E15 5E14 70 80 90 100 Temperature (K Methane (CH 4 : 4.9 10-21 kg cm -2 s -1

Radiolysis-Induced Cyanide (CN - Formation at 10 K 0.35 0.30 0.20 0.10 Wavelength (µm 2.5 3 4 8 12 1620 A ν 3 (NH 3 2ν 4 ν 1 NH 3 CH 4 NH 3 C n H 2n+2 (n = 1 6 ν 3 (CH 4 ν 4 (CH 4 a: ν 1 (CH 4 b: ν 2 +ν 4 (CH 4 c: 2ν 4 (CH 4 ν 4 (NH 3 ν 2 (NH 3 0.12 0.08 0.04 Wavelength (µm 2.5 3 4 8 12 1620 B ν 3 (NH 3 2ν 4 ν 1 ν as (-CH 3 ν as (-CH 2 - ν s (-CH 3 δ as (-CH 3 δ(-ch 2 - ν 4 (NH 3 ν 2 (NH 3 δ s (-CH 3 a: H 6 ρ(-ch 2 - Absorbance 0.00 0.35 0.30 d,e,f,g,h: H 6 a b c Absorbance 0.00 0.12 a 0.20 0.08 ν 3 (CH 4 0.10 d e f δ(nh 2 ν 2 (CH 3 0.04 ν 4 (CH 4 δ(nh 2 a: H 6 ω(=ch 2 g CN - h 0.00 4000 3500 3000 2500 2000 1500 1000 500 Wavenumber (cm -1 CN - 0.00 4000 3500 3000 2500 2000 1500 1000 500 Wavenumber (cm -1 a

Temporal Evolution of CN - at 10 K 8.00E+015 A B C Scheme 6.00E+015 0.1 µa 4.00E+015 A C Scheme column density, cm -2 2.00E+015 0.00E+000 7.00E+015 6.00E+015 1 µa k 1 A NH 3 / C n H 2n+2 ; n =1-6 NH 3 / CH 4 -H -H NH 2 / CH 3 4.00E+015 k B: CH 3 NH 2 2.00E+015 0.00E+000 0 5 10 15 20 time, minutes k 2 C -2H/H 2 CH 2 NH +Ba -2H/H 2 -HBa + CN -

Methylamine (CH 3 NH 2 Formation via Radical-Radical Recombination during Warm-up Gas Phase Wavelength (µm 3.3 4 5 6 8 10 12 0.024 A Solid Phase (113 K 1E-7 1E-9 1E-11 A 1E-13 1E-7 B m/z=17 m/z=30 m/z=31 Absorbance CH 3 NH 2 0.016 ν 3 (MA ν 12 /ν 5 (MA 0.008 0.000 3000 2500 2000 1500 1000 800 Wavenumber (cm -1 Kim & Kaiser ApJ 729, 68 (2011 Current (A 1E-9 1E-11 1E-13 1E-7 1E-9 1E-11 1E-13 1E-7 1E-9 1E-11 m/z=17 30,31 C m/z=30 D m/z=17 30,31 1E-13 50 60 90 120 150 180 Temperature (K

Aminoacetonitrile (NH 2 CH 2 CN Production in Sgr B2(N Constrain the formation mechanism of Aminoacetonitrile (NH 2 CH 2 CN on Icy grains: Strecker-type synthesis CH 2 =NH + CN - + HBase + NH 2 CH 2 CN + Base vs. Radiolysis at as low as 10 K CH 2 =NH / H CN CH 2 =NH / H + CN CH 2 NH 2 / CN NH 2 CH 2 CN k 1 A NH 3 / C n H 2n+2 ; n =1-6 NH 3 / CH 4 -H -H NH 2 / CH 3 k Miao et al. 1995 k 2 B: C CH 3 NH 2-2H/H 2 CH 2 NH +Ba -2H/H 2 -HBa + CN -

Acknowledgements