Laboratory Chemistry of the Outer Solar System Marla Moore NASA/Goddard Space Flight Center

1. Laboratory Chemistry of the Outer Solar System Marla Moore NASA/Goddard Space Flight Center January 28, 2008 Polar GatewaysArctic Circle Sunrise 2008, Barrow Alaska Cosmic Ice Lab

2. What we do ? Laboratory radiation chemistry of relevant outer solar system ices. What we need! A good understanding of outer solar system environments, e.g.: Temperature Radiation environment Ice composition of surfaces Laboratory ChemistryGoal Help explain observations and predict likely new products yet to be discovered

3. 50 years ago Temperature – calculated – assuming black bodies T ≈ 300 r -1/2 Radiation environment Cosmic ray energy spectrum of primary cosmic rays was known Launch of Explorer I— discovery of Van Allen radiation belts e.g. Pluto 55 K Explorer I. January 31, 1958

4. 50 years ago Ice Composition Near-Infrared water-ice feature detected on: Mars polar cap Rings of Saturn Europa and Ganymede Suspected water ice on inner satellites of Saturn based on reflectivity Gerald Kuiper Laboratory radiation chemistry 1953 (origin of life study) gas phase mixtures 1957-1960 (rocket fuel?) Frozen free radical experiments John Oro 1963 ( comets) 77 K mixture H2O+CH4+NH3 5 MeV electrons

5. Some Ice Environments KBOs methane nitrogen carbon monoxide carbon dioxide ammonia water

6. 50 years ago Solar System Ices

7. * Solar System Ices * * * Based onTable 4 from T. Roush, JGR, 2001

8. 50 years ago Cometary Molecules Water Methane Ammonia

9. Cometary Molecules

10. Photolysis /Magnetospheric Radiolysis

11. How do we study ices in the laboratory ?

12. Laboratory Set-Up Vacuum 10−7 mm Hg MeV p+ Ice at 10K Infrared Spectrum H2O CO2 Gas NH3 Infrared Light

13. IR Spectrometer UV p+

14. Examples • 1. H2O2 and sulfur--Europa • 2. Fate of methane--Pluto • 3. If methanol then sugar ? --Comets

15. EUROPA H2O, SO2, SH, CO2, CH, XCN, H2O2, H2SO4, carbonate salt, hydrous sulfate 10-2 10-1 100 101 102 Energy MeV 10-2

16. Laboratory ice studies used to: IDENTIFY Hydrogen Peroxide on Europa

17. Laboratory ice studies shows that on Europa p+ H2O + SO2 Sulfuric acid

18. PLUTO N2 CH4-methane CO Irradiated methane forms ethane and propane The dashed curve shows the spectrum of a mixture of C2H2:C2H6:CH4 (Sasaki et al., 2005) Pluto spectrum

19. COMET HALE-BOPP

20. H2O + CO, T= 15 K (~108 yr) Methanol

21. Ethylene Glycol Discovered in 2002 in the ISM & in Comet Hale-Bopp in 2004! (Hollis et al., 2000) (Crovisier et al., 2004) Methanol 7% 12% 20% 40%

22. Ethylene Glycol Glycolaldehyde p+ Discovered in the ISM (Hollis et al., 2002)

23. Looking to the future--------

24. Room temperature residues

25. New Tools for Chemical Analyses Gas Chromatography Mass Spectrometry GC-MS GC MS Liquid Chromatography Mass Spectrometry LC-MS HPLC & Detectors MS

26. New Horizons will reach the Pluto system in July 2015 The ESA Rosetta spacecraft will reach comet 67P/Churyumov-Gerasimenko in 2014

27. SUMMARY • Radiation processing complex molecules, and ions • Reactions generally understood • Laboratory work predicts new molecules and ions awaiting detection

28. Reggie Hudson Reggie Hudson Robert Ferrante Paul Cooper Reggie Hudson Robert Ferrante Paul Cooper Collaborators Reggie Hudson

29. www-691.gsfc.nasa.gov/cosmic.ice.lab

30. Interstellar Molecules