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An experimental study of the surface formation of methane in interstellar molecular clouds

Abstract

Methane is one of the simplest stable molecules that is both abundant and widely distributed across space. Observational surveys of CH4 ice towards low- and high-mass young stellar objects showed that much of the CH4 is expected to be formed by the hydrogenation of C on dust grains, and that CH4 ice is strongly correlated with solid H2O. However, this has not been investigated under controlled laboratory conditions. Here, we successfully demonstrate with a C-atom beam implemented in an ultrahigh vacuum apparatus the formation of CH4 ice in two separate co-deposition experiments: C + H on a 10 K surface to mimic CH4 formation directly before H2O ice is formed on the dust grain, and C + H + H2O on a 10 K surface to mimic CH4 formed simultaneously with H2O ice. We confirm that CH4 can be formed by the reaction of atomic C and H, and that the CH4 formation rate is twice as high when CH4 is formed within a H2O-rich ice. This is in agreement with the observational finding that interstellar CH4 and H2O form together in the polar ice phase. The conditions that lead to interstellar CH4 (and CD4) ice formation are reported, and can be incorporated into astrochemical models to further constrain CH4 chemistry in the interstellar medium and in other regions where CH4 is inherited.

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Fig. 1: Visualization of the two experiments highlighted in this study.
Fig. 2: RAIRS spectra of CH4 formation acquired after co-deposition in two different experiments, in which only the selected feature of interest is shown (that is, CH4 ν4 mode).

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Data availability

The data that support the figures and table within this paper and other findings of this study are available from the corresponding author upon reasonable request.

References

  1. Boogert, A., Gerakines, P. A. & Whittet, D. C. Observations of the icy universe. Annu. Rev. Astron. Astrophys. 53, 541–581 (2015).

    Article  ADS  Google Scholar 

  2. Öberg, K. I. et al. The c2d Spitzer spectroscopic survey of ices around low-mass young stellar objects. III. CH4. Astrophys. J. 678, 1032–1041 (2008).

    Article  ADS  Google Scholar 

  3. Aikawa, Y., Wakelam, V., Garrod, R. T. & Herbst, E. Molecular evolution and star formation: from prestellar cores to protostellar cores. Astrophys. J. 674, 993–1005 (2008).

    Article  ADS  Google Scholar 

  4. Cuppen, H. et al. Grain surface models and data for astrochemistry. Space Sci. Rev. 212, 1–58 (2017).

    Article  ADS  Google Scholar 

  5. Nuth III, J. A., Charnley, S. B. & Johnson, N. M. in Meteorites and the Early Solar System II (eds Lauretta, D. & McSween, H.) 147–167 (Univ. of Arizona, 2006).

  6. Smith, I. W. Effects of quantum mechanical tunneling on rates of radiative association. Astrophys. J. 347, 282–288 (1989).

    Article  ADS  Google Scholar 

  7. Mumma, M. J. et al. Detection of abundant ethane and methane, along with carbon monoxide and water, in comet C/1996 B2 Hyakutake: evidence for interstellar origin. Science 272, 1310–1314 (1996).

    Article  ADS  Google Scholar 

  8. Gibb, E., Mumma, M., Russo, N. D., DiSanti, M. & Magee-Sauer, K. Methane in Oort cloud comets. Icarus 165, 391–406 (2003).

    Article  ADS  Google Scholar 

  9. Formisano, V., Atreya, S., Encrenaz, T., Ignatiev, N. & Giuranna, M. Detection of methane in the atmosphere of Mars. Science 306, 1758–1761 (2004).

    Article  ADS  Google Scholar 

  10. Swain, M. R., Vasisht, G. & Tinetti, G. The presence of methane in the atmosphere of an extrasolar planet. Nature 452, 329–331 (2008).

    Article  ADS  Google Scholar 

  11. Stern, S. et al. The Pluto system: initial results from its exploration by New Horizons. Science 350, aad1815 (2015).

    Article  ADS  Google Scholar 

  12. Mousis, O., Gautier, D. & Coustenis, A. The D/H ratio in methane in Titan: origin and history. Icarus 159, 156–165 (2002).

    Article  ADS  Google Scholar 

  13. Mousis, O. et al. A primordial origin for the atmospheric methane of Saturn’s moon Titan. Icarus 204, 749–751 (2009).

    Article  ADS  Google Scholar 

  14. Bar-Nun, A., Litman, M. & Rappaport, M. Interstellar molecules: hydrocarbon formation on graphite grains at T ≥ 7 K. Astron. Astrophys. 85, 197–200 (1980).

    ADS  Google Scholar 

  15. Hiraoka, K., Miyagoshi, T., Takayama, T., Yamamoto, K. & Kihara, Y. Gas-grain processes for the formation of CH4 and H2O: reactions of H atoms with C, O, and CO in the solid phase at 12 K. Astrophys. J. 498, 710–715 (1998).

    Article  ADS  Google Scholar 

  16. Chapados, C. & Cabana, A. Infrared spectra and structures of solid CH4 and CD4 in phases I and II. Can. J. Chem. 50, 3521–3533 (1972).

    Article  ADS  Google Scholar 

  17. Baulch, D. et al. Evaluated kinetic data for combustion modelling. J. Phys. Chem. Ref. Data 21, 411–734 (1992).

    Article  ADS  Google Scholar 

  18. Harding, L. B., Guadagnini, R. & Schatz, G. C. Theoretical studies of the reactions H + CH → C + H2 and C + H2 → CH2 using an ab initio global ground-state potential surface for CH2. J. Phys. Chem. 97, 5472–5481 (1993).

    Article  Google Scholar 

  19. Corchado, J. C., Bravo, J. L. & Espinosa-Garcia, J. The hydrogen abstraction reaction H + CH4. I. New analytical potential energy surface based on fitting to ab initio calculations. J. Chem. Phys. 130, 184314 (2009).

    Article  ADS  Google Scholar 

  20. Öberg, K. I., van Dishoeck, E. F., Linnartz, H. & Andersson, S. The effect of H2O on ice photochemistry. Astrophys. J. 718, 832–840 (2010).

    Article  ADS  Google Scholar 

  21. Veeraghattam, V. K., Manrodt, K., Lewis, S. P. & Stancil, P. The sticking of atomic hydrogen on amorphous water ice. Astrophys. J. 790, 4 (2014).

    Article  ADS  Google Scholar 

  22. Mayer, E. & Pletzer, R. Astrophysical implications of amorphous ice—a microporous solid. Nature 319, 298–301 (1986).

    Article  ADS  Google Scholar 

  23. Lepetit, B., Lemoine, D., Medina, Z. & Jackson, B. Sticking and desorption of hydrogen on graphite: a comparative study of different models. J. Chem. Phys. 134, 114705 (2011).

    Article  ADS  Google Scholar 

  24. Albar, J. et al. An atomic carbon source for high temperature molecular beam epitaxy of graphene. Sci. Rep. 7, 6598 (2017).

    Article  ADS  Google Scholar 

  25. Fuchs, G. et al. Hydrogenation reactions in interstellar CO ice analogues—a combined experimental/theoretical approach. Astron. Astrophys. 505, 629–639 (2009).

    Article  ADS  Google Scholar 

  26. Ioppolo, S., Cuppen, H., Romanzin, C., van Dishoeck, E. F. & Linnartz, H. Water formation at low temperatures by surface O2 hydrogenation I: characterization of ice penetration. Phys. Chem. Chem. Phys. 12, 12065–12076 (2010).

    Article  Google Scholar 

  27. Chuang, K.-J., Fedoseev, G., Ioppolo, S., van Dishoeck, E. F. & Linnartz, H. H-atom addition and abstraction reactions in mixed CO, H2CO and CH3OH ices—an extended view on complex organic molecule formation. Mon. Not. R. Astron. Soc. 455, 1702–1712 (2016).

    Article  ADS  Google Scholar 

  28. Bosman, A. D., Walsh, C. & van Dishoeck, E. F. CO destruction in protoplanetary disk midplanes: inside versus outside the CO snow surface. Astron. Astrophys. 618, A182 (2018).

    Article  Google Scholar 

  29. Fedoseev, G., Ioppolo, S., Zhao, D., Lamberts, T. & Linnartz, H. Low-temperature surface formation of NH3 and HNCO: hydrogenation of nitrogen atoms in CO-rich interstellar ice analogues. Mon. Not. R. Astron. Soc. 446, 439–448 (2014).

    Article  ADS  Google Scholar 

  30. Ioppolo, S., Cuppen, H., Romanzin, C., van Dishoeck, E. F. & Linnartz, H. Laboratory evidence for efficient water formation in interstellar ices. Astrophys. J. 686, 1474–1479 (2008).

    Article  ADS  Google Scholar 

  31. Charnley, S. On the nature of interstellar organic chemistry. In IAUC 161: Astronomical and Biochemical Origins and the Search for Life in the Universe (eds Cosmovici, C., Bowyer, S. & Werthimer, D.) 89–96 (Warsaw Technical Univ., 1997).

  32. Charnley, S. Interstellar organic chemistry. In The Bridge between the Big Bang and Biology: Stars, Planetary Systems, Atmospheres, Volcanoes: their Link to Life (ed. Giovannelli, F.) 139–149 (Consiglio Nazionale delle Ricerche, 2001).

  33. Charnley, S. & Rodgers, S. Pathways to molecular complexity. In IAUC 231: Astrochemistry: Recent Successes and Current Challenges (eds Lis, D., Blake, G. & Herbst, E.) Vol. 1, 237–246 (Cambridge Univ. Press, 2005).

  34. Charnley, S. & Rodgers, S. Theoretical models of complex molecule formation on dust. In Bioastronomy 2007: Molecules, Microbes and Extraterrestrial Life (eds. Meech, K., Keane, J., Mumma, M., Siefert, J. & Werthimer, D.) Vol. 420, 29–34 (Astronomical Society of the Pacific, 2009).

  35. Ioppolo, S., Fedoseev, G., Lamberts, T., Romanzin, C. & Linnartz, H. SURFRESIDE2 : an ultrahigh vacuum system for the investigation of surface reaction routes of interstellar interest. Rev. Sci. Instrum. 84, 1–13 (2013).

    Article  Google Scholar 

  36. Qasim, D. et al. Alcohols on the rocks: solid-state formation in a H3CC≡CH + OH cocktail under dark cloud conditions. ACS Earth Space Chem. 3, 986–999 (2019).

    Article  Google Scholar 

  37. Guadagnini, R. & Schatz, G. C. Unusual insertion mechanism in the reaction C(3P) + H2 → CH + H. J. Phys. Chem. 100, 18944–18949 (1996).

    Article  Google Scholar 

  38. Tschersich, K. & Von Bonin, V. Formation of an atomic hydrogen beam by a hot capillary. J. Appl. Phys. 84, 4065–4070 (1998).

    Article  ADS  Google Scholar 

  39. Tschersich, K. Intensity of a source of atomic hydrogen based on a hot capillary. J. Appl. Phys. 87, 2565–2573 (2000).

    Article  ADS  Google Scholar 

  40. Tschersich, K., Fleischhauer, J. & Schuler, H. Design and characterization of a thermal hydrogen atom source. J. Appl. Phys. 104, 1–7 (2008).

    Article  Google Scholar 

  41. Bouilloud, M. et al. Bibliographic review and new measurements of the infrared band strengths of pure molecules at 25 K: H2O, CO2, CO, CH4, NH3, CH3 OH, HCOOH and H2CO. Mon. Not. R. Astron. Soc. 451, 2145–2160 (2015).

    Article  ADS  Google Scholar 

  42. Addepalli, V. & Rao, N. R. Infrared intensity analysis of molecules. 1. CH2D2, CH2T2 and CD2T2 and CH4, CD4 and CT4. Indian J. Pure Appl. Phys. 14, 117–121 (1976).

    Google Scholar 

  43. Chuang, K.-J. et al. Reactive desorption of CO hydrogenation products under cold pre-stellar core conditions. Astrophys. J. 853, 1–9 (2018).

    Article  Google Scholar 

Download references

Acknowledgements

This research benefited from financial support by the Dutch Astrochemistry Network II (DANII). Further support includes a VICI grant from NWO (the Netherlands Organization for Scientific Research) and A-ERC grant 291141 CHEMPLAN. Funding by NOVA (the Netherlands Research School for Astronomy) is acknowledged. D.Q. acknowledges J. Bouwman and E. Fayolle for stimulating discussions. S.I. recognizes the Royal Society for financial support and the Holland Research School for Molecular Chemistry (HRSMC) for a travel grant.

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Authors and Affiliations

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Contributions

D.Q. performed the experiments and wrote the manuscript. D.Q. and G.F. designed the experiments and analysed the data. K.-J.C. helped with column density measurements and error calculations. J.H. and S.I. provided insights on the surface formation mechanism. E.F.v.D. and H.L. generously assisted with the astrochemical implications. H.L. initiated the project. All authors participated in discussion of the experiments, analysis and interpretation of the results and shaping of the manuscript.

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Correspondence to D. Qasim.

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Peer review information Nature Astronomy thanks Martin McCoustra and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

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Supplementary Figs. 1–4 and text.

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Qasim, D., Fedoseev, G., Chuang, KJ. et al. An experimental study of the surface formation of methane in interstellar molecular clouds. Nat Astron 4, 781–785 (2020). https://doi.org/10.1038/s41550-020-1054-y

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