Photosynthesis and Photo-Stability of Nucleic Acids in Prebiotic Extraterrestrial Environments

  • Scott A. SandfordEmail author
  • Partha P. Bera
  • Timothy J. Lee
  • Christopher K. Materese
  • Michel Nuevo
Part of the Topics in Current Chemistry book series (TOPCURRCHEM, volume 356)


Laboratory experiments have shown that the UV photo-irradiation of low-temperature ices of astrophysical interest leads to the formation of organic molecules, including molecules important for biology such as amino acids, quinones, and amphiphiles. When pyrimidine is introduced into these ices, the products of irradiation include the nucleobases uracil, cytosine, and thymine, the informational sub-units of DNA and RNA, as well as some of their isomers. The formation of these compounds, which has been studied both experimentally and theoretically, requires a succession of additions of OH, NH2, and CH3 groups to pyrimidine. Results show that H2O ice plays key roles in the formation of the nucleobases, as an oxidant, as a matrix in which reactions can take place, and as a catalyst that assists proton abstraction from intermediate compounds. As H2O is also the most abundant icy component in most cold astrophysical environments, it probably plays the same roles in space in the formation of biologically relevant compounds. Results also show that although the formation of uracil and cytosine from pyrimidine in ices is fairly straightforward, the formation of thymine is not. This is mostly due to the fact that methylation is a limiting step for its formation, particularly in H2O-rich ices, where methylation must compete with oxidation. The relative inefficiency of the abiotic formation of thymine to that of uracil and cytosine, together with the fact that thymine has not been detected in meteorites, are not inconsistent with the RNA world hypothesis. Indeed, a lack of abiotically produced thymine delivered to the early Earth may have forced the choice for an RNA world, in which only uracil and cytosine are needed, but not thymine.


Astrochemistry Extraterrestrial abiotic nucleobase synthesis Ice irradiation Nucleobases UV irradiation 



The authors are grateful for support from the NASA Origins of Solar Systems, Exobiology, and Astrophysics Research and Analysis, and Astrobiology Programs. Much of the work reported in this chapter also benefited from support of postdoctoral researchers under the NASA Postdoctoral Program. PPB and TJL would like to acknowledge financial support from NASA to investigate the formation and evolution of carbon-based material in the universe. This manuscript benefited from the helpful comments of an anonymous reviewer.


  1. 1.
    Miller SL (1953) A production of amino acids under possible primitive Earth conditions. Science 117:528–529Google Scholar
  2. 2.
    Levine JS, Augustsson TR, Natarajan M (1982) The prebiological paleoatmosphere: stability and composition. Orig Life 12:245–259Google Scholar
  3. 3.
    Hayes JM (1967) Organic constituents of meteorites – a review. Geochim Cosmochim Acta 31:1395–1440Google Scholar
  4. 4.
    Kvenvolden K, Lawless J, Pering K, Peterson E, Flores J, Ponnamperuma C (1970) Evidence for extraterrestrial amino-acids and hydrocarbons in the Murchison meteorite. Nature 228:923–926Google Scholar
  5. 5.
    Mullie F, Reisse J (1987) Organic matter in carbonaceous chondrites. Top Curr Chem 139:85–117Google Scholar
  6. 6.
    Cronin JR, Chang S (1993) Organic matter in meteorites: molecular and isotopic analyses of the Murchison meteorite. NATO Advanced Study Institute and International School of Space Chemistry: The chemistry of life’s origins. Kluwer Academic Publisher; Springer, The Netherlands, pp 209–258Google Scholar
  7. 7.
    Irvine WM (1998) Extraterrestrial organic matter: a review. Orig Life Evol Biosph 28:365–383Google Scholar
  8. 8.
    Cooper G, Kimmich N, Belisle W, Sarinana J, Brabham K, Garrel L (2001) Carbonaceous meteorites as a source of sugar-related organic compounds for the early Earth. Nature 414:879–883Google Scholar
  9. 9.
    Pizzarello S, Huang Y (2003) Carbon isotopic analyses of individual Murchison amino acids. Geochim Cosmochim Acta Suppl 67:380Google Scholar
  10. 10.
    Martins Z, Alexander CMO’D, Orzechowska GE, Fogel ML, Ehrenfreund P (2007) Indigenous amino acids in primitive CR meteorites. Meteor Planet Sci 42:2125–2136Google Scholar
  11. 11.
    Martins Z, Botta O, Fogel ML, Sephton MA, Glavin DP, Watson JS, Dworkin JP, Schwartz AW, Ehrenfreund P (2008) Extraterrestrial nucleobases in the Murchison meteorite. Earth Planet Sci Lett 270:130–136Google Scholar
  12. 12.
    Oró J (1961) Comets and the formation of biochemical compounds on the primitive Earth. Nature 190:389–390Google Scholar
  13. 13.
    Oró J (1961) Mechanisms of synthesis of adenine from hydrogen cyanide under possible primitive Earth conditions. Nature 191:1193–1194Google Scholar
  14. 14.
    Delsemme AH (1998) Cosmic origin of the biosphere. In: Brack A (ed) The molecular origin of life. Cambridge University Press, CambridgeGoogle Scholar
  15. 15.
    Prinn RG, Fegley B Jr (1987) Bolide impacts, acid rain, and biospheric traumas at the Cretaceous-Tertiary boundary. Earth Planet Sci Lett 83:1–15Google Scholar
  16. 16.
    Chyba CF (1990) Impact delivery and erosion of planetary oceans in the early inner solar system. Nature 343:129–133Google Scholar
  17. 17.
    Chyba C, Sagan C (1992) Endogenous production, exogenous delivery and impact-shock synthesis of organic molecules: an inventory for the origins of life. Nature 355:125–132Google Scholar
  18. 18.
    Strecker A (1850) Über die künstliche Bildung der Milchsäure und einen neuen, dem Glycocoll homologen Körper. Justus Liebigs Ann Chem 75:27–45 (In German)Google Scholar
  19. 19.
    Taillades J, Beuzelin I, Garrel L, Tabacik V, Bied C, Commeyras A (1998) N-Carbamoyl-α-amino acids rather than free α-amino acids formation in the primitive hydrosphere: a novel proposal for the emergence of prebiotic peptides. Orig Life Evol Biosph 28:61–77Google Scholar
  20. 20.
    Bücherer HT, Fischbeck HTJ (1934) Prakt Chem Adv Synth Catal 140:69–89Google Scholar
  21. 21.
    Schloerb FP, Kinzel WM, Swade DA, Irvine WM (1986) HCN production from comet Halley. Astrophys J 310:L55–L60Google Scholar
  22. 22.
    Ip W-H, Balsiger H, Geiss J, Goldstein BE, Kettmann G, Lazarus AJ, Meier A, Rosenbauer H, Schwenn R, Shelley E (1990) Giotto IMS measurements of the production rate of hydrogen cyanide in the coma of Comet Halley. Ann Geophys 8:319–325Google Scholar
  23. 23.
    Jones PA, Sarkissian JM, Burton MG, Voronkov MA, Filipović MD (2006) Radio observations of Comet 9P/Tempel 1 with the Australia Telescope facilities during the Deep Impact encounter. Month Not R Astron Soc 369:1995–2000Google Scholar
  24. 24.
    Biver N, Bockelée-Morvan D, Boissier J, Crovisier J, Colom P, Lecacheux A, Moreno R, Paubert G, Lis DC, Sumner M, Frisk U, Hjalmarson Å, Olberg M, Winnberg A, Florén H-G, Sandqvist A, Kwok S (2007) Radio observations of Comet 9P/Tempel 1 before and after Deep Impact. Icarus 191:494–512Google Scholar
  25. 25.
    Disanti MA, Villanueva GL, Bonev BP, Magee-Sauer K, Lyke JE, Mumma MJ (2007) Temporal evolution of parent volatiles and dust in Comet 9P/Tempel 1 resulting from the Deep Impact experiment. Icarus 191:481–493Google Scholar
  26. 26.
    Lis DC, Bockelée-Morvan D, Boissier J, Crovisier J, Biver N, Charnley SB (2008) Hydrogen isocyanide in Comet 73P/Schwassmann-Wachmann (Fragment B). Astrophys J 675:931–936Google Scholar
  27. 27.
    Jehin E, Bockelée-Morvan D, Dello Russo N, Manfroid J, Hutsemékers D, Kawakita H, Kobayashi H, Schulz R, Smette A, Stüwe J, Weiler M, Arpigny C, Biver N, Cochran A, Crovisier J, Magain P, Rauer H, Sana H, Vervack RJ, Weaver H, Zucconi J-M (2009) A multi-wavelength simultaneous study of the composition of the Halley family Comet 8P/Tuttle. Earth Moon Planets 105:343–349Google Scholar
  28. 28.
    Gibb EL, Bonev BP, Villanueva G, DiSanti MA, Mumma MJ, Sudholt E, Radeva Y (2012) Chemical composition of comet C/2007 N3 (Lulin): another “Atypical” comet. Astrophys J 750:102 (14 pp)Google Scholar
  29. 29.
    Loren RB, Wootten HA (1978) Star formation in the bright-rimmed molecular cloud IC 1848 A. Astrophys J 225:L81–L84Google Scholar
  30. 30.
    Zuckerman B, Dyck HM (1986) Dust grains and gas in the circumstellar envelopes around luminous red giant stars. Astrophys J 311:345–359Google Scholar
  31. 31.
    McMullin JP, Mundy LG, Blake GA (1994) The circumstellar environment of IRAS 05338-0624. Astrophys J 437:305–316Google Scholar
  32. 32.
    Jørgensen JK, Hogerheijde MR, van Dishoeck EF, Blake GA, Schöier FL (2004) The structure of the NGC 1333-IRAS2 protostellar system on 500 AU scales. An infalling envelope, a circumstellar disk, multiple outflows, and chemistry. Astron Astrophys 413:993–1007Google Scholar
  33. 33.
    Thi W-F, van Zadelhoff G-J, van Dishoeck EF (2004) Organic molecules in protoplanetary disks around T Tauri and Herbig Ae stars. Astron Astrophys 425:955–972Google Scholar
  34. 34.
    Decin L, De Beck E, Brünken S, Müller HSP, Menten KM, Kim H, Willacy K, de Koter A, Wyrowski F (2010) Circumstellar molecular composition of the oxygen-rich AGB star IK Tauri. II. In-depth non-LTE chemical abundance analysis. Astron Astrophys 516:23 id. A69Google Scholar
  35. 35.
    Matthews CN, Moser RE (1967) Peptide synthesis from hydrogen cyanide and water. Nature 215:1230–1234Google Scholar
  36. 36.
    Toupance G, Sebban G, Buvet R (1970) Etape initiale de la polymérisation de l’acide cyanhydrique et synthèses prébiologiques. J Chim Phys 67:1870–1874 (In French)Google Scholar
  37. 37.
    Matthews CN (1979) HCN did not condense to give heteropolypeptides on the primitive Earth (reply to Ferris 1979). Science 16:1136–1137Google Scholar
  38. 38.
    Ferris JP (1979) HCN did not condense to give heteropolypeptides on the primitive Earth. Science 16:1135–1137Google Scholar
  39. 39.
    Ferris JP, Hagan WJ (1984) HCN and chemical evolution: the possible role of cyano compounds in prebiotic synthesis. Tetrahedron 40:1093–1120Google Scholar
  40. 40.
    Roy D, Najafian K, von Ragué Schleyer P (2007) Chemical evolution: the mechanism of the formation of adenine under prebiotic conditions. Proc Natl Acad Sci 104:17272–17277Google Scholar
  41. 41.
    Ferris JP, Sanchez RA, Orgel LE (1968) Studies in prebiotic synthesis – III. Synthesis of pyrimidine from cyanoacethylene and cyanate. J Mol Biol 33:693–704Google Scholar
  42. 42.
    Butlerow A (1961) Formation synthétique d’une substance sucrée. C R Acad Sci 53:145–147 (In French)Google Scholar
  43. 43.
    Müller D, Pitsch S, Kittaka A, Wagner E, Wintner CE, Eschenmoser A (1990) Chemie von α-Aminonitrilen. Aldomerisierung von Glycolaldehyd-Phosphat zu racemischen Hexose-2,4,6-triphosphaten und (in Gegenwart von Formaldehyd) racemischen Pentose-2,4-diphosphaten: rac-Allose-2,4,6-triphosphat und rac-Ribose-2,4,-diphosphat sind die Reaktionshauptprodukte. Helv Chim Acta 73:1410–1468 (In German)Google Scholar
  44. 44.
    Weber AL (1998) Prebiotic amino acid thioester synthesis: thiol-dependent amino acid synthesis from formose substrates (formaldehyde and glycolaldehyde) and ammonia. Orig Life Evol Biosph 28:259–270Google Scholar
  45. 45.
    Jalbout AF (2008) Prebiotic synthesis of simple sugars by an interstellar formose reaction. Orig Life Evol Biosph 38:489–497Google Scholar
  46. 46.
    Jalbout AF, Abrell L, Adamowicz L, Polt R, Apponi AJ, Ziurys LM (2007) Sugar synthesis from a gas-phase formose reaction. Astrobiology 7:433–442Google Scholar
  47. 47.
    Ben-Naim A (1980) Hydrophobic interactions. Plenum Press, New YorkGoogle Scholar
  48. 48.
    Dworkin JP, Deamer DW, Sandford SA, Allamandola LJ (2001) Self-assembling amphiphilic molecules: synthesis in simulated interstellar/precometary ices. Proc Natl Acad Sci 98:815–819Google Scholar
  49. 49.
    Nissenbaum A (1976) Scavenging of soluble organic matter from the prebiotic oceans. Orig Life 7:413–416Google Scholar
  50. 50.
    Siegel BZ, Siegel SM (1981) Enzyme-mimicking properties of silicates and other minerals. Adv Space Res 1:27–36Google Scholar
  51. 51.
    Maurette M (1998) Carbonaceous micrometeorites and the origin of life. Orig Life Evol Biosph 4/6:385–412Google Scholar
  52. 52.
    Schulte M, Blake D, Hoehler T, McCollom T (2006) Serpentinization and its implications for life on the early Earth and Mars. Astrobiology 6:364–376Google Scholar
  53. 53.
    Vázquez-Mayagoitia Á, Horton SR, Sumpter BG, Sponer J, Sponer JE, Fuentes-Cabrera M (2011) On the stabilization of ribose by silicate minerals. Astrobiology 11:115–121Google Scholar
  54. 54.
    Ertem G (2004) Montmorillonite, oligonucleotides, RNA and origin of life. Orig Life Evol Biosph 34:549–570Google Scholar
  55. 55.
    Arribas M, de Vicente A, Arias A, Lázaro E (2005) Effect of metallic cations on the efficiency of DNA amplification. Implications for nucleic acid replication during early stages of life. Int J Astrobiol 4:115–123Google Scholar
  56. 56.
    Tielens AGGM, Allamandola LJ (1987) Composition, structure, and chemistry of interstellar dust. In: Hollenbach D, Thronson H (eds) Interstellar processes. D. Reidel, Dordrecht, pp 397–469Google Scholar
  57. 57.
    Dorschner J, Henning T (1995) Dust metamorphosis in the galaxy. Astron Astrophys Rev 6:271–333Google Scholar
  58. 58.
    Sandford SA, Allamandola LJ, Tielens AGGM, Sellgren K, Tapia M, Pendleton Y (1991) The interstellar C-H stretching band near 3.4 μm: constraints on the composition of organic material in the diffuse interstellar medium. Astrophys J 371:607–620Google Scholar
  59. 59.
    d’Hendecourt L, Jourdain de Muizon M, Dartois E, Breitfellner M, Ehrenfreund P, Bénit J, Boulanger F, Puget JL, Habing HJ (1996) ISO-SWS observations of solid state features towards RAFGL 7009S. Astron Astrophys 315:L365–L368Google Scholar
  60. 60.
    Pendleton YJ, Allamandola LJ (2002) The organic refractory material in the diffuse interstellar medium: mid-infrared spectroscopic constraints. Astrophys J Suppl Ser 138:75–98Google Scholar
  61. 61.
    Allamandola LJ, Tielens AGGM, Barker JR (1989) Interstellar polycyclic aromatic hydrocarbons – the infrared emission bands, the excitation/emission mechanism, and the astrophysical implications. Astrophys J Suppl Ser 71:733–775Google Scholar
  62. 62.
    Puget JL, Léger A (1989) A new component of the interstellar matter – small grains and large aromatic molecules. Ann Rev Astron Astrophys 27:161–198Google Scholar
  63. 63.
    Roelfsema PR, Cox P, Tielens AGGM, Allamandola LJ, Baluteau JP, Barlow MJ, Beintema D, Boxhoorn DR, Cassinelli JP, Caux E, Churchwell E, Clegg PE, de Graauw T, Heras AM, Huygen R, van der Hucht KA, Hudgins DM, Kessler MF, Lim T, Sandford SA (1996) SWS observations of IR emission features towards compact HII regions. Astron Astrophys 315:L289–L292Google Scholar
  64. 64.
    Galliano F, Madden SC, Tielens AGGM, Peeters E, Jones AP (2008) Variations of the mid-IR aromatic features inside and among galaxies. Astrophys J 679:310–345Google Scholar
  65. 65.
    d’Hendecourt LB, Allamandola LJ, Greenberg JM (1985) Time dependent chemistry in dense molecular clouds. I – Grain surface reactions, gas/grain interactions and infrared spectroscopy. Astron Astrophys 152:130–150Google Scholar
  66. 66.
    Shen CJ, Greenberg JM, Schutte WA, van Dishoeck EF (2004) Cosmic ray induced explosive chemical desorption in dense clouds. Astron Astrophys 415:203–215Google Scholar
  67. 67.
    Millar TJ, Roueff E, Charnley SB, Rodgers SD (1995) The chemistry of complex molecules in interstellar clouds. Int J Mass Spectrom Ion Proc 149/150:389–402Google Scholar
  68. 68.
    Charnley S (1997) On the nature of interstellar organic chemistry. In: Cosmovici CB, Bowyer S, Werthimer D (eds) Astronomical and biochemical origins and the search for life in the universe, proceeding of the 5th international conferece on bioastronomy, IAU Coll. #161. Kluwer Academic, Dordrecht, pp 89–96Google Scholar
  69. 69.
    Müller HSP, Endres CP, Stutzki J, Schlemmer S (2013) Molecules in space. Physikalisches Institut, Universität zu Köln. Accessed 10 June 2013
  70. 70.
    Greenberg MJ (1984) The structure and evolution of interstellar grains. Sci Am 250:96–107Google Scholar
  71. 71.
    Bernstein MP, Sandford SA, Allamandola LJ, Chang S, Scharberg MA (1995) Organic compounds produced by photolysis of realistic interstellar and cometary ice analogs containing methanol. Astrophys J 454:327–344Google Scholar
  72. 72.
    Dworkin JP, Gillette JS, Bernstein MP, Sandford SA, Allamandola LJ, Elsila JE, McGlothlin DR, Zare RN (2004) An evolutionary connection between interstellar ices and IDPs? Clues from mass spectroscopy measurements of laboratory simulations. Adv Spa Res 33:67–71Google Scholar
  73. 73.
    Simon MN, Simon M (1973) Search for interstellar acrylonitrile, pyrimidine, and pyridine. Astrophys J 184:757–762Google Scholar
  74. 74.
    Kuan Y-J, Yan C-H, Charnley SB, Kisiel Z, Ehrenfreund P, Huang H-C (2003) A search for interstellar pyrimidine. Month Not R Astron Soc 345:650–656Google Scholar
  75. 75.
    Kuan Y-J, Charnley SB, Huang H-C, Kisiel Z, Ehrenfreund P, Tseng W-L, Yan C-H (2004) Searches for interstellar molecules of potential prebiotic importance. Adv Space Res 33:31–39Google Scholar
  76. 76.
    Charnley SB, Kuan Y-J, Huang H-C, Botta O, Butner HM, Cox N, Despois D, Ehrenfreund P, Kisiel Z, Lee Y-Y, Markwick AJ, Peeters Z, Rodgers SD (2005) Astronomical searches for nitrogen heterocycles. Adv Space Res 36:137–145Google Scholar
  77. 77.
    Brünken S, McCarthy MC, Thaddeus P, Godfrey PD, Brown RD (2006) Improved line frequencies for the nucleic acid base uracil for a radioastronomical search. Astron Astrophys 459:317–320Google Scholar
  78. 78.
    Sandford SA, Bernstein MP, Allamandola LJ (2004) The mid-infrared laboratory spectra of naphthalene (C10H8) in solid H2O. Astrophys J 607:346–360Google Scholar
  79. 79.
    Bernstein MP, Sandford SA, Allamandola LJ (2005) The mid-infrared absorption spectra of neutral polycyclic aromatic hydrocarbons in conditions relevant to dense interstellar clouds. Astrophys J Suppl Ser 161:53–64Google Scholar
  80. 80.
    Chyba CF, Thomas PJ, Brookshaw L, Sagan C (1990) Cometary delivery of organic molecules to the early Earth. Science 249:366–373Google Scholar
  81. 81.
    Baldwin B, Sheaffer Y (1971) Ablation and breakup of large meteoroids during atmospheric entry. J Geophys Res Space Phys 76(#19):4653–4668Google Scholar
  82. 82.
    Fraundorf P (1980) The distribution of temperature maxima for micrometeorites decelerated in the Earth’s atmosphere without heating. Geophys Res Lett 10:765–768Google Scholar
  83. 83.
    Deamer DW, Fleischaker GR (1994) Origins of life: the central concepts. Jones & Bartlett Publisher, BostonGoogle Scholar
  84. 84.
    Lazcano A, Miller SL (1996) The origin and early evolution of life: prebiotic chemistry, the pre-RNA world, and time. Cell 85:793–798Google Scholar
  85. 85.
    Orgel LE (2004) Prebiotic chemistry and the origin of the RNA world. Crit Rev Biochem Mol Biol 39:99–123Google Scholar
  86. 86.
    Miller SL, Cleaves HJ (2006) Prebiotic chemistry on the primitive Earth. In: Rigoutsos I, Stephanopoulos G (eds) Systems biology, genomics, vol I. Oxford University Press, Oxford, pp 4–56Google Scholar
  87. 87.
    Powner MW, Sutherland JD, Szostak JW (2010) Chemoselective multicomponent one-pot assembly of purine precursors in water. J Am Chem Soc 132:16677–16688Google Scholar
  88. 88.
    Whittet DCB, Schutte WA, Tielens AGGM, Boogert ACA, de Graauw T, Ehrenfreund P, Gerakines PA, Helmich FP, Prusti T, van Dishoeck EF (1996) An ISO SWS view of interstellar ices: first results. Astron Astrophys 315:L357–L360Google Scholar
  89. 89.
    Lacy JH, Faraji H, Sandford SA, Allamandola LJ (1998) Unraveling the 10 micron “silicate” feature of protostars: the detection of frozen interstellar ammonia. Astrophys J Lett 501:L105–L109Google Scholar
  90. 90.
    Ehrenfreund P, Charnley SB (2000) Organic molecules in the interstellar medium, comets, and meteorites: a voyage from dark clouds to the early Earth. Ann Rev Astron Astrophys 38:427–483Google Scholar
  91. 91.
    Gibb EL, Whittet DCB, Schutte WA, Boogert ACA, Chiar JE, Ehrenfreund P, Gerakines PA, Keane JV, Tielens AGGM, van Dishoeck EF, Kerkhof O (2000) An inventory of interstellar ices toward the embedded protostar W33A. Astrophys J 536:347–356Google Scholar
  92. 92.
    Gibb EL, Whittet DCB, Boogert ACA, Tielens AGGM (2004) Interstellar ice: the infrared space observatory legacy. Astrophys J Suppl Ser 151:35–73Google Scholar
  93. 93.
    Dartois E (2005) The ice survey opportunity of ISO. Space Sci Rev 119:293–310Google Scholar
  94. 94.
    Lacy JH, Baas F, Allamandola LJ, van de Bult CEP, Persson SE, McGregor PJ, Lonsdale CJ, Geballe TR (1984) 4.6 Micron absorption features due to solid phase CO and cyano group molecules toward compact infrared sources. Astrophys J 276:533–543Google Scholar
  95. 95.
    Thi W-F, van Dishoeck EF, Dartois E, Pontoppidan KM, Schutte WA, Ehrenfreund P, d’Hendecourt L, Fraser HJ (2006) VLT–ISAAC 3-5 μm spectroscopy of embedded young low-mass stars. III. Intermediate-mass sources in Vela. Astron Astrophys 449:251–265Google Scholar
  96. 96.
    Schutte WA, Greenberg JM (1997) Further evidence for the OCN assignment to the XCN band in astrophysical ice analogs. Astron Astrophys 317:L43–L46Google Scholar
  97. 97.
    Demyk K, Dartois E, d’Hendecourt L, Jourdain de Muizon M, Heras AM, Breitfellner M (1998) Laboratory identification of the 4.62 μm solid state absorption band in the ISO-SWS spectrum of RAFGL 7009S. Astron Astrophys 339:553–560Google Scholar
  98. 98.
    van Broekhuizen FA, Keane JV, Schutte WA (2004) A quantitative analysis of OCN formation in interstellar ice analogs. Astron Astrophys 415:425–436Google Scholar
  99. 99.
    Bernstein MP, Dworkin JP, Sandford SA, Cooper GW, Allamandola LJ (2002a) Racemic amino acids from the ultraviolet photolysis of interstellar ice analogues. Nature 416:401–403Google Scholar
  100. 100.
    Muñoz Caro GM, Meierhenrich UJ, Schutte WA, Barbier B, Arcones Segovia A, Rosenbauer H, Thiemann WH-P, Brack A, Greenberg JM (2002) Amino acids from ultraviolet irradiation of interstellar ice analogues. Nature 416:403–406Google Scholar
  101. 101.
    Nuevo M, Chen Y-J, Yih T-S, Ip W-H, Fung H-S, Cheng C-Y, Tsai H-R, Wu C-YR (2007) Amino acids formed from the UV/EUV irradiation of inorganic ices of astrophysical interest. Adv Space Res 40:1628–1633Google Scholar
  102. 102.
    Nuevo M, Auger G, Blanot D, d’Hendecourt L (2008) A detailed study of the amino acids produced from the vacuum UV irradiation of interstellar ice analogs. Orig Life Evol Biosph 38:37–56Google Scholar
  103. 103.
    Nuevo M, Bredehöft JH, Meierhenrich UJ, d’Hendecourt L, Thiemann WH-P (2010) Urea, glycolic acid, and glycerol in an organic residue produced by ultraviolet irradiation of interstellar/pre-cometary ice analogs. Astrobiology 10:245–256Google Scholar
  104. 104.
    de Marcellus P, Bertrand M, Nuevo M, Westall F, Le Sergeant d’Hendecourt L (2011) Prebiotic significance of extraterrestrial ice photochemistry: detection of hydantoin in organic residues. Astrobiology 11:847–854Google Scholar
  105. 105.
    Bernstein MP, Sandford SA, Allamandola LJ, Gillette JS, Clemett SJ, Zare RN (1999) UV irradiation of polycyclic aromatic hydrocarbons in ices: production of alcohols, quinones, and ethers. Science 283:1135–1138Google Scholar
  106. 106.
    Bernstein MP, Dworkin JP, Sandford SA, Allamandola LJ (2001) Ultraviolet irradiation of naphthalene in H2O ice: implications for meteorites and biogenesis. Meteorit Planet Sci 36:351–358Google Scholar
  107. 107.
    Bernstein MP, Elsila JE, Dworkin JP, Sandford SA, Allamandola LJ, Zare RN (2002) Side group addition to the PAH coronene by UV photolysis in cosmic ice analogs. Astrophys J 576:1115–1120Google Scholar
  108. 108.
    Bernstein MP, Moore MH, Elsila JE, Sandford SA, Allamandola LJ, Zare RN (2003) Side group addition to the PAH coronene by proton irradiation in cosmic ice analogs. Astrophys J 582:L25–L29Google Scholar
  109. 109.
    Ashbourn SFM, Elsila JE, Dworkin JP, Bernstein MP, Sandford SA, Allamandola LJ (2007) Ultraviolet photolysis of anthracene in H2O interstellar ice analogs: potential connection to meteoritic organics. Meteorit Planet Sci 42:2035–2041Google Scholar
  110. 110.
    Nuevo M, Milam SN, Sandford SA, Elsila JE, Dworkin JP (2009) Formation of uracil from the ultraviolet photo-irradiation of pyrimidine in pure H2O ices. Astrobiology 9:683–695Google Scholar
  111. 111.
    Nuevo M, Milam SN, Sandford SA (2012) Nucleobases and prebiotic molecules in organic residues produced from the ultraviolet photo-irradiation of pyrimidine in NH3 and H2O+NH3 ices. Astrobiology 12:295–314Google Scholar
  112. 112.
    Materese CK, Nuevo M, Bera PP, Lee TJ, Sandford SA (2013) Thymine and other prebiotic molecules produced from the ultraviolet photo-irradiation of pyrimidine in simple astrophysical ice analogs. Astrobiology 13:948–962Google Scholar
  113. 113.
    Gerakines PA, Moore MH, Hudson RL (2000) Carbonic acid production in H2O:CO2 ices. UV photolysis vs. proton bombardment. Astron Astrophys 357:793–800Google Scholar
  114. 114.
    Gerakines PA, Moore MH, Hudson RL (2001) Energetic processing of laboratory ice analogs: UV photolysis versus ion bombardment. J Geophys Res 106:33381–33386Google Scholar
  115. 115.
    Gerakines PA, Moore MH, Hudson RL (2004) Ultraviolet photolysis and proton irradiation of astrophysical ice analogs containing hydrogen cyanide. Icarus 170:202–213Google Scholar
  116. 116.
    Elsila JE, Dworkin JP, Bernstein MP, Martin MP, Sandford SA (2007) Mechanisms of amino acid formation in interstellar ice analogs. Astrophys J 660:911–918Google Scholar
  117. 117.
    Sandford SA, Bernstein MP, Materese CK (2013) The infrared spectra of polycyclic aromatic hydrocarbons with excess peripheral H atoms (Hn-PAHs) and their relation to the 3.4 and 6.9 μm PAH emission features. Astrophys J Suppl 205:30 id 8Google Scholar
  118. 118.
    Dodd RT (1981) Meteorites: a petrologic-chemical synthesis. Cambridge University Press, CambridgeGoogle Scholar
  119. 119.
    Lauretta DS, McSween HY Jr (eds) (2006) Meteorites and the early Solar System II. University Arizona Press, TucsonGoogle Scholar
  120. 120.
    Pizzarello S, Cooper GW, Flynn GJ (2006) The nature and distribution of the organic material in carbonaceous chondrites and interplanetary dust particles. In: Lauretta DS, McSween HY Jr (eds) Meteorites and the early Solar System II. University of Arizona Press, Tucson, pp 625–651Google Scholar
  121. 121.
    Cody GD, Alexander CMO’D, Tera F (2002) Solid-state (1H and 13C) nuclear magnetic resonance spectroscopy of insoluble organic residue in the Murchison meteorite: a self-consistent quantitative analysis. Geochim Cosmochim Acta 66:1851–1865Google Scholar
  122. 122.
    Alexander CMO’D, Fogel M, Yabuta H, Cody GD (2007) The origin and evolution of chondrites recorded in the elemental and isotopic compositions of their macromolecular organic matter. Geochim Cosmochim Acta 71:4380–4403Google Scholar
  123. 123.
    Kerridge JF, Chang S, Shipp R (1987) Isotopic characterization of kerogen-like material in the Murchison carbonaceous chondrite. Geochim Cosmochim Acta 51:2527–2540Google Scholar
  124. 124.
    Cronin JR, Pizzarello S (1997) Enantiomeric excesses in meteoritic amino acids. Science 275:951–955Google Scholar
  125. 125.
    Sephton MA, Wright IP, Gilmour I, de Leeuw JW, Grady MM, Pillinger CT (2002) High molecular weight organic matter in Martian meteorites. Planet Space Sci 50:711–716Google Scholar
  126. 126.
    Glavin DP, Dworkin JP, Aubrey A, Botta O, Doty JH, Martins Z, Bada JL (2006) Amino acid analyses of Antarctic CM2 meteorites using liquid chromatography-time of flight-mass spectrometry. Meteorit Planet Sci 41:889–902Google Scholar
  127. 127.
    Burton AS, Elsila JE, Hein JE, Glavin DP, Dworkin JP (2013) Extraterrestrial amino acids identified in metal-rich CH and CB carbonaceous chondrites from Antarctica. Meteorit Planet Sci 48:390–402Google Scholar
  128. 128.
    Hayatsu R (1964) Orgueil meteorite: organic nitrogen contents. Science 146:1291–1293Google Scholar
  129. 129.
    Folsome CE, Lawless J, Romiez M, Ponnamperuma C (1971) Heterocyclic compounds indigenous to the Murchison meteorite. Nature 232:108–109Google Scholar
  130. 130.
    Hayatsu R, Anders E, Studier MH, Moore LP (1975) Purines and triazines in the Murchison meteorite. Geochim Cosmochim Acta 39:471–488Google Scholar
  131. 131.
    van der Velden W, Schwartz AW (1977) Search for purines and pyrimidines in the Murchison meteorite. Geochim Cosmochim Acta 41:961–968Google Scholar
  132. 132.
    Stoks PG, Schwartz AW (1979) Uracil in carbonaceous meteorites. Nature 282:709–710Google Scholar
  133. 133.
    Stoks PG, Schwartz AW (1981) Nitrogen-heterocyclic compounds in meteorites – significance and mechanisms of formation. Geochim Cosmochim Acta 45:563–569Google Scholar
  134. 134.
    Callahan MP, Smith KE, Cleaves HJ II, Ruzicka J, Stern JC, Glavin DP, House CH, Dworkin JP (2011) Carbonaceous meteorites contain a wide range of extraterrestrial nucleobases. Proc Natl Acad Sci 108:13995–13998Google Scholar
  135. 135.
    Folsome CE, Lawless J, Romiez M, Ponnamperuma C (1973) Heterocyclic compounds recovered from carbonaceous chondrites. Geochim Cosmochim Acta 37:455–465Google Scholar
  136. 136.
    Engel MH, Macko SA (1997) Isotopic evidence for extraterrestrial non-racemic amino acids in the Murchison meteorite. Nature 389:265–268Google Scholar
  137. 137.
    Cronin JR, Pizzarello S (1999) Amino acid enantiomer excesses in meteorites: origin and significance. Adv Space Res 23:293–299Google Scholar
  138. 138.
    Pizzarello S, Zolensky M, Turk KA (2003) Nonracemic isovaline in the Murchison meteorite: chiral distribution and mineral association. Geochim Cosmochim Acta 67:1589–1595Google Scholar
  139. 139.
    Glavin DP, Elsila JE, Burton AS, Callahan MP, Dworkin JP, Hilts RW, Herd CDK (2012) Unusual nonterrestrial L-proteinogenic amino acid excesses in the Tagish Lake meteorite. Meteorit Planet Sci 47:1347–1364Google Scholar
  140. 140.
    Callahan MP, Burton AS, Elsila JE, Baker EM, Smith KE, Glavin DP, Dworkin JP (2013) A search for amino acids and nucleobases in the Martian meteorite Roberts Massif 04262 using liquid chromatography-mass spectrometry. Meteorit Planet Sci 48:786–795Google Scholar
  141. 141.
    Shapiro R (1999) Prebiotic cytosine synthesis: a critical analysis and implications for the origin of life. Proc Natl Acad Sci 96:4396–4401Google Scholar
  142. 142.
    Nelson KE, Robertson MP, Levy M, Miller SL (2001) Concentration by evaporation and prebiotic synthesis of cytosine. Orig Life Evol Biosph 31:221–229Google Scholar
  143. 143.
    Callahan MP, Stern JC, Glavin DP, Whelley KE, Martin MG, Dworkin JP (2010) Distribution of nucleobases in CM and CR carbonaceous chondrites. Astrobiology science conference 2010: evolution and life: surviving catastrophes and extremes on Earth and beyond, April 26–30, 2010 in League City, LPI Contribution No. 1538, p 5160Google Scholar
  144. 144.
    Boulanger E, Anoop A, Nachtigallova D, Thiel W, Barbatti M (2013) Photochemical steps in the prebiotic synthesis of purine precursors from HCN. Angew Chem Int Ed 52:8000–8003Google Scholar
  145. 145.
    Bera PP, Lee TJ, Schaefer HF III (2009) Are isomers of vinyl cyanide missing links of interstellar pyrimidine formation? J Chem Phys 131:7, id. 074303Google Scholar
  146. 146.
    Raulin F (1991) Bioastronomy: the search for extraterrestial life—the exploration broadens, vol 390, Lecture Notes in Physics. Springer, Berlin, Heidelberg, pp 141–148Google Scholar
  147. 147.
    Lis DC, Mehringer DM, Benford D, Gardner M, Phillips TG, Bockelée-Morvan D, Biver N, Colom P, Crovisier J, Despois D, Rauer H (1997) New molecular species in Comet C/1995 O1 (Hale-Bopp) observed with the Caltech Submillimeter Observatory. Earth Moon Planets 78:13–20Google Scholar
  148. 148.
    Biver N, Bockelée-Morvan D, Colom P, Crovisier J, Paubert G, Weiss A, Wiesemeyer H (2011) Molecular investigations of comets C/2002 X5 (Kudo-Fujikawa), C/2002 V1 (NEAT), and C/2006 P1 (McNaught) at small heliocentric distances. Astron Astrophys 528(A142):19Google Scholar
  149. 149.
    Dello Russo N, Vervack RJ Jr, Lisse CM, Weaver HA, Kawakita H, Kobayashi H, Cochran AL, Harris WM, McKay AJ, Biver N, Bockelée-Morvan D, Crovisier J (2011) The volatile composition and activity of Comet 103P/Hartley 2 during the EPOXI closest approach. Astrophys J Lett 734:6, pp. id. L8Google Scholar
  150. 150.
    Jewell PR, Snyder LE (1982) New circumstellar cyanoacetylene sources. Astrophys J 255:L69–L73Google Scholar
  151. 151.
    Jewell PR, Snyder LE (1984) Observations and analysis of circumstellar cyanoacetylene. Astrophys J 278:176–185Google Scholar
  152. 152.
    Huang H-C, Kuan Y-J, Charnley SB, Hirano N, Takakuwa S, Bourke TL (2005) Organic molecules in the hot corinos and circumstellar disks of IRAS 16293-2422. Adv Space Res 36:146–155Google Scholar
  153. 153.
    Pardo JR, Cernicharo J, Goicoechea JR (2005) Observational evidence of the formation of cyanopolyynes in CRL 618 through the polymerization of HCN. Astrophys J 628:275–282Google Scholar
  154. 154.
    Kunde VG, Aikin AC, Hanel RA, Jennings DE, Maguire WC, Samuelson RE (1981) C4H2, HC3N and C2N2 in Titan’s atmosphere. Nature 292:686–688Google Scholar
  155. 155.
    Coustenis A, Bézard B, Gautier D, Marten A, Samuelson R (1991) Titan’s atmosphere from Voyager infrared observations. III – Vertical contributions of hydrocarbons and nitriles near Titan’s north pole. Icarus 89:152–167Google Scholar
  156. 156.
    Bénilan Y, Andrieux D, Khlifi M, Bruston P, Raulin F, Guillemin J-C, Cossart-Magos C (1996) Temperature dependence of HC3N, C6H2, and C4N2 mid-UV absorption coefficients. Application to the interpretation of Titan's atmospheric spectra. Astrophys Space Sci 236:85–95Google Scholar
  157. 157.
    Khanna RK (2005) Condensed species in Titan’s stratosphere: confirmation of crystalline cyanoacetylene (HC3N) and evidence for crystalline acetylene (C2H2) on Titan. Icarus 178:165–170Google Scholar
  158. 158.
    Chang S, Scattergood T, Aronowitz S, Flores J (1979) Organic chemistry on Titan. Rev Geophys Space Phys 17:1923–1933Google Scholar
  159. 159.
    Capone LA, Prasad SS, Huntress WT, Whitten RC, Dubach J, Santhanam K (1981) Formation of organic molecules on Titan. Nature 293:45–46Google Scholar
  160. 160.
    Gupta SK, Ochiai E, Ponnamperuma C (1981) Organic synthesis in the atmosphere of Titan. Nature 293:725–727Google Scholar
  161. 161.
    Raulin F, Coll P, Coscia D, Gazeau M-C, Sternberg R, Bruston P, Israël G, Gautier D (1998) An exobiological view of Titan and the Cassini–Huygens mission. Adv Space Res 22:353–362Google Scholar
  162. 162.
    Vuitton V, Yelle RV, Lavvas P, Klippenstein SJ (2012) Rapid association reactions at low pressure: impact on the formation of hydrocarbons on Titan. Astrophys J 744(11):7Google Scholar
  163. 163.
    Horn A, Møllendal H, Guillemin J-C (2008) A quantum chemical study of the generation of a potential prebiotic compound, cyanoacetaldehyde, and related sulfur containing species. J Phys Chem A 112:11009–11016Google Scholar
  164. 164.
    Frenklach M, Feigelson ED (1989) Formation of polycyclic aromatic hydrocarbons in circumstellar envelopes. Astrophys J 341:372–384Google Scholar
  165. 165.
    Ricca A, Bauschlicher CW, Bakes ELO (2001) A computational study of the mechanisms for the incorporation of a nitrogen atom into polycyclic aromatic hydrocarbons in the Titan haze. Icarus 154:516–521Google Scholar
  166. 166.
    Bera PP, Head-Gordon M, Lee TJ (2011) Initiating molecular growth in the interstellar medium via complexes of observed ions and molecules. Astron Astrophys 535:12Google Scholar
  167. 167.
    McElroy D, Walsh C, Markwick AJ, Cordiner MA, Smith K, Millar TJ (2013) The UMIST database for astrochemistry 2012. Astron Astrophys 550(A36):13Google Scholar
  168. 168.
    Peeters Z, Botta O, Charnley SB, Kisiel Z, Kuan Y-J, Ehrenfreund P (2005) Formation and photostability of N-heterocycles in space. I. The effect of nitrogen on the photostability of small aromatic molecules. Astron Astrophys 433:583–590Google Scholar
  169. 169.
    Hudgins DM, Sandford SA (1998) Infrared spectroscopy of matrix-isolated polycyclic aromatic hydrocarbons 1. PAHs containing 2 to 4 rings. J Phys Chem A 102:329–343Google Scholar
  170. 170.
    Hudgins DM, Sandford SA (1998) Infrared spectroscopy of matrix-isolated polycyclic aromatic hydrocarbons 2. PAHs containing 5 or more rings. J Phys Chem A 102:344–352Google Scholar
  171. 171.
    Ruiterkamp R, Peeters Z, Moore MH, Hudson RL, Ehrenfreund P (2005) A quantitative study of proton irradiation and UV photolysis of benzene in interstellar environments. Astron Astrophy 440:391–402Google Scholar
  172. 172.
    Satzger H, Townsend D, Zgierski MZ, Patchkovskii S, Ullrich S, Stolow A (2006) Primary processes underlying the photostability of isolated DNA bases: adenine. Proc Natl Acad Sci 103:10196–10201Google Scholar
  173. 173.
    Fondren LD, McLain J, Jackson DM, Adams NG, Babcock LM (2007) Studies of reactions of a series of ions with nitrogen containing heterocyclic molecules molecules using a selected ion flow tube. Int J Mass Spectrom 265:60–67Google Scholar
  174. 174.
    Bera PP, Schaefer HF III (2006) Lesions in DNA subunits: the nucleic acid bases. In trends and perspectives in modern computational science, vol 6. Brill Academic Publishers, Boston, pp 254–264Google Scholar
  175. 175.
    Gilbert W (1986) Origin of life: the RNA world. Nature 319:618Google Scholar
  176. 176.
    Joyce GF (1989) RNA evolution and the origin of life. Nature 338:217–224Google Scholar
  177. 177.
    Joyce GF (2002) The antiquity of RNA-based evolution. Nature 418:214–221Google Scholar
  178. 178.
    Warnek P (1962) A microwave-powered hydrogen lamp for vacuum ultraviolet photochemical research. Appl Optics 1:721–726Google Scholar
  179. 179.
    Mathis JS, Mezger PG, Panagia N (1983) Interstellar radiation field and dust temperatures in the diffuse interstellar matter and in giant molecular clouds. Astron Astrophys 128:212–229Google Scholar
  180. 180.
    Prasad SS, Tarafdar SP (1983) UV radiation field inside dense clouds—its possible existence and chemical implications. Astrophys J 267:603–609Google Scholar
  181. 181.
    Bera PP, Nuevo M, Milam SN, Sandford SA, Lee TJ (2010) Mechanism for the abiotic synthesis of uracil via UV-induced oxidation of pyrimidine in pure H2O ices under astrophysical conditions. J Chem Phys 133(10):104303Google Scholar
  182. 182.
    Becke AD (1993) Density functional thermochemistry. III. The role of exact exchange. J Chem Phys 98(7):5648–5652Google Scholar
  183. 183.
    Lee CT, Yang WT, Parr RG (1988) Development of the Colle-Salvetti correlation-energy formula into a functional of the electron density. Phys Rev B 37:785–789Google Scholar
  184. 184.
    Hehre WJ, Ditchfield R, Pople JA (1972) Self-consistent molecular orbital methods. XII. Further extensions of Gaussian-type basis sets for use in molecular orbital studies of organic molecules. J Chem Phys 56:2257–2261Google Scholar
  185. 185.
    Lee TJ, Jayatilaka D (1993) An open-shell restricted Hartree–Fock perturbation theory based on symmetric spin orbitals. Chem Phys Lett 201:1–10Google Scholar
  186. 186.
    Lee TJ, Rendell AP, Dyall KG, Jayatilaka D (1994) Open-shell restricted Hartree–Fock perturbation theory: some considerations and comparisons. J Chem Phys 100:10 id. 7400Google Scholar
  187. 187.
    Dunning TH (1989) Gaussian-basis sets for use in correlated molecular calculations. 1. The atoms boron through neon and hydrogen. J Chem Phys 90:1007–1024Google Scholar
  188. 188.
    Shao Y, Molnar LF, Jung Y, Kussmann J, Ochsenfeld C, Brown ST, Gilbert ATB, Slipchenko LV, Levchenko SV, O’Neill DP, DiStasio RA, Lochan RC, Wang T, Beran GJO, Besley NA, Herbert JM, Lin CY, Van Voorhis T, Chien SH, Sodt A, Steele RP, Rassolov VA, Maslen PE, Korambath PP, Adamson RD, Austin B, Baker J, Byrd EFC, Dachsel H, Doerksen RJ, Dreuw A, Dunietz BD, Dutoi AD, Furlani TR, Gwaltney SR, Heyden A, Hirata S, Hsu CP, Kedziora G, Khalliulin RZ, Klunzinger P, Lee AM, Lee MS, Liang W, Lotan I, Nair N, Peters B, Proynov EI, Pieniazek PA, Rhee YM, Ritchie J, Rosta E, Sherrill CD, Simmonett AC, Subotnik JE, Woodcock HL, Zhang W, Bell AT, Chakraborty AK, Chipman DM, Keil FJ, Warshel A, Hehre WJ, Schaefer HF, Kong J, Krylov AI, Gill PMW, Head-Gordon M (2006) Advances in methods and algorithms in a modern quantum chemistry program package. Phys Chem Chem Phys 8:3172–3191Google Scholar
  189. 189.
    Engel V, Staemmler V, van der Wal RL, Crim FF, Sension RJ, Hudson B, Anderson P, Hennig S, Weide K, Shinke R (1992) Photodissociation of water in the first absorption band: a protoype for dissociation in a repulsive potential energy surface. J Phys Chem 96:3201–3213Google Scholar
  190. 190.
    Mordaunt DH, Dixon RN, Ashfold MNR (1996) Photodissociation dynamics of à state ammonia molecules. II. The isotopic dependence for partially and fully deuterated isotopomers. J Chem Phys 104:6472–6481Google Scholar
  191. 191.
    Woon DE (2002) Pathways to glycine and other amino acids in ultraviolet irradiated astrophysical ices determined via quantum chemical modeling. Astrophys J 571:177–180Google Scholar
  192. 192.
    Rice J, Bera PP, Lee TJ (2013) Ab initio quantum chemical study of formation of cytosine under astrophysical conditions. J Chem Phys, in preparationGoogle Scholar
  193. 193.
    Öberg KI, Garrod RT, van Dishoeck EF, Linnartz H (2009) Formation rates of complex organics in UV irradiated CH3OH-rich ices. I. Experiments. Astron Astrophys 504:891–913Google Scholar
  194. 194.
    Elsila JE, Hammond MR, Bernstein MP, Sandford SA, Zare RN (2006) UV photolysis of quinoline in interstellar ice analogs. Meteorit Planet Sci 41:785–796Google Scholar
  195. 195.
    Bera PP, Nuevo M, Mataerese CK, Sandford SA, Lee TJ (2013) The formation of thymine under astrophysical conditions constrains its role in the origin of life: theoretical study. Astrobiology, in preparationGoogle Scholar
  196. 196.
    Shapiro R (2006) Small molecule interactions were central to the origin of life. Q Rev Biol 81:105–126Google Scholar
  197. 197.
    Bernstein MP, Sandford SA, Allamandola LJ (1999) Life’s far-flung raw materials [interstellar organic molecules]. Sci Am 281:26–33Google Scholar
  198. 198.
    Sandford SA, Allamandola LJ (1993) H2 in interstellar and extragalactic ices: infrared characteristics, UV production, and implications. Astrophys J Lett 409:L65–L68Google Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2014

Authors and Affiliations

  • Scott A. Sandford
    • 1
    Email author
  • Partha P. Bera
    • 1
    • 2
  • Timothy J. Lee
    • 1
  • Christopher K. Materese
    • 1
  • Michel Nuevo
    • 1
    • 3
  1. 1.Space Science and Astrobiology DivisionNASA Ames Research CenterMoffett FieldUSA
  2. 2.Bay Area Environmental Research InstituteSonomaUSA
  3. 3.SETI InstituteMountain ViewUSA

Personalised recommendations