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X-ray photodesorption from water ice in protoplanetary disks and X-ray-dominated regions

Abstract

Water is the main constituent of interstellar ices, and it plays a key role in the evolution of many regions of the interstellar medium, from molecular clouds to planet-forming disks1. In cold regions of the interstellar medium, water is expected to be completely frozen out onto the dust grains. Nonetheless, observations indicate the presence of cold water vapour, implying that non-thermal desorption mechanisms are at play. Photodesorption by ultraviolet photons has been proposed to explain these observations2,3, with the support of extensive experimental and theoretical work on ice analogues4,5,6. In contrast, photodesorption by X-rays, another viable mechanism, has been little studied. The potential of this process to desorb key molecules such as water, intact rather than fragmented or ionized, remains unexplored. We experimentally investigated X-ray photodesorption from water ice, monitoring all desorbing species. We found that desorption of neutral water is efficient, while ion desorption is minor. We derived yields that can be implemented in astrochemical models. These results open up the possibility of taking into account the X-ray photodesorption process in the modelling of protoplanetary disks or X-ray-dominated regions.

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Fig. 1: Schematic representation of a vertical slice of a protoplanetary disk.
Fig. 2: Photodesorption yields of the neutral species observed, as a function of photon energy.

References

  1. 1.

    van Dishoeck, E. F., Bergin, E. A., Lis, D. C. & Lunine, J. I. in Protostars and Planets VI (eds Beuther, H. et al.) 835–858 (Univ. Arizona Press, Tucson, 2014).

  2. 2.

    Hogerheijde, M. R. et al. Detection of the water reservoir in a forming planetary system. Science 334, 338–340 (2011).

    ADS  Article  Google Scholar 

  3. 3.

    Caselli, P. et al. First detection of water vapor in a pre-stellar core. Astrophys. J. Lett. 759, L37 (2012).

    ADS  Article  Google Scholar 

  4. 4.

    Arasa, C., Koning, J., Kroes, G.-J., Walsh, C. & van Dishoeck, E. F. Photodesorption of H2O, HDO, and D2O ice and its impact on fractionation. Astron. Astrophys. 575, A121 (2015).

    Article  Google Scholar 

  5. 5.

    Muñoz Caro, G. M. et al. Photodesorption and physical properties of CO ice as a function of temperature. Astron. Astrophys. 589, A19 (2016).

    Article  Google Scholar 

  6. 6.

    Bertin, M. et al. UV photodesorption of methanol in pure and CO-rich ices: desorption rates of the intact molecules and the photofragments. Astrophys. J. Lett. 817, L12 (2016).

    ADS  Article  Google Scholar 

  7. 7.

    Aikawa, Y. & Herbst, E. Molecular evolution in protoplanetary disks. Two-dimensional distributions and column densities of gaseous molecules. Astron. Astrophys. 351, 233–246 (1999).

    ADS  Google Scholar 

  8. 8.

    Walsh, C., Nomura, H., Millar, T. J. & Aikawa, Y. Chemical processes in protoplanetary disks. II. On the importance of photochemistry and X-ray ionization. Astrophys. J. 747, 114 (2012).

    ADS  Article  Google Scholar 

  9. 9.

    Maloney, P. R., Hollenbach, D. J. & Tielens, A. G. G. M. X-ray-irradiated molecular gas. I. Physical processes and general results. Astrophys. J. 466, 561–584 (1996).

    ADS  Article  Google Scholar 

  10. 10.

    Meijerink, R., Spaans, M. & Israel, F. P. Diagnostics of irradiated dense gas in galaxy nuclei. II. A grid of XDR and PDR models. Astron. Astrophys. 461, 793–811 (2007).

    ADS  Article  Google Scholar 

  11. 11.

    Walsh, C., Millar, T. J. & Nomura, H. Chemical processes in protoplanetary disks. Astrophys. J. 722, 1607–1623 (2010).

    ADS  Article  Google Scholar 

  12. 12.

    Stäuber, P., Jørgensen, J. K., van Dishoeck, E. F., Doty, S. D. & Benz, A. O. Water destruction by X-rays in young stellar objects. Astron. Astrophys. 453, 555–565 (2006).

    ADS  Article  Google Scholar 

  13. 13.

    Cleeves, L. I., Bergin, E. A., Qi, C., Adams, F. C. & Öberg, K. I. Constraining the X-ray and cosmic-ray ionization chemistry of the TW Hya protoplanetary disk: evidence for a sub-interstellar cosmic-ray rate. Astrophys. J. 799, 204 (2015).

    ADS  Article  Google Scholar 

  14. 14.

    Rosenberg, R. A.et al. K-shell excitation of D2O and H2O ice: photoion and photoelectron yields. Phys. Rev. B 28, 3026–3030 1983).

    ADS  Article  Google Scholar 

  15. 15.

    Coulman, D. et al. Excitation, deexcitation, and fragmentation in the core region of condensed and adsorbed water. J. Chem. Phys. 93, 58–75 (1990).

    ADS  Article  Google Scholar 

  16. 16.

    Mase, K., Nagasono, M., Tanaka, S.-i, Sekitani, T. & Nagaoka, S.-i Ion desorption from molecules condensed at low temperature: a study with electron-ion coincidence spectroscopy combined with synchrotron radiation (review). Low Temp. Phys. 29, 243–258 (2003).

    ADS  Article  Google Scholar 

  17. 17.

    Pilling, S. & Andrade, D. P. P. in X-Ray Spectroscopy (ed. Sharma, S. K.) Ch. 10 (InTech, London, 2012); https://doi.org/10.5772/29591

    Google Scholar 

  18. 18.

    Nilsson, A. et al. X-ray absorption spectroscopy and X-ray Raman scattering of water and ice; an experimental view. J. Electron Spectrosc. 177, 99–129 (2010).

    Article  Google Scholar 

  19. 19.

    Parent, P., Laffon, C., Mangeney, C., Bournel, F. & Tronc, M. Structure of the water ice surface studied by X-ray absorption spectroscopy at the O K-edge. J. Chem. Phys. 117, 10842–10851 (2002).

    ADS  Article  Google Scholar 

  20. 20.

    Laffon, C., Lacombe, S., Bournel, F. & Parent, P. Radiation effects in water ice: a near-edge X-ray absorption fine structure study. J. Chem. Phys. 125, 204714 (2006).

    ADS  Article  Google Scholar 

  21. 21.

    Petrik, N. G. & Kimmel, G. A. Electron-stimulated sputtering of thin amorphous solid water films on Pt(111). J. Chem. Phys. 123, 054702 (2005).

    ADS  Article  Google Scholar 

  22. 22.

    Yabushita, A., Hama, T. & Kawasaki, M. Photochemical reaction processes during vacuum-ultraviolet irradiation of water ice. J. Photoch. Photobio. C 16, 46–61 (2013).

    Article  Google Scholar 

  23. 23.

    Cruz-Diaz, G. A., Martn-Doménech, R., Moreno, E., Muñoz Caro, G. M. & Chen, Y.-J. New measurements on water ice photodesorption and product formation under ultraviolet irradiation. Mon. Not. R. Astron. Soc. 474, 3080–3089 (2018).

    ADS  Article  Google Scholar 

  24. 24.

    Arasa, C., Andersson, S., Cuppen, H. M., van Dishoeck, E. F. & Kroes, G.-J. Molecular dynamics simulations of the ice temperature dependence of water ice photodesorption. J. Chem. Phys. 132, 184510 (2010).

    ADS  Article  Google Scholar 

  25. 25.

    Nomura, H., Aikawa, Y., Tsujimoto, M., Nakagawa, Y. & Millar, T. J. Molecular hydrogen emission from protoplanetary disks. II. Effects of X-ray irradiation and dust evolution. Astrophys. J. 661, 334–353 (2007).

    ADS  Article  Google Scholar 

  26. 26.

    Braito, V. et al. The XMM-Newton and BeppoSAX view of the ultra luminous infrared galaxy MKN 231. Astron. Astrophys. 420, 79–88 (2004).

    ADS  Article  Google Scholar 

  27. 27.

    Cecchi-Pestellini, C. & Aiello, S. Cosmic ray induced photons in dense interstellar clouds. Mon. Not. R. Astron. Soc. 258, 125–133 (1992).

    ADS  Article  Google Scholar 

  28. 28.

    Dartois, E. et al. Heavy ion irradiation of crystalline water ice: cosmic ray amorphisation cross-section and sputtering yield. Astron. Astrophys. 576, A125 (2015).

    Article  Google Scholar 

  29. 29.

    Walsh, C., Nomura, H. & van Dishoeck, E. The molecular composition of the planet-forming regions of protoplanetary disks across the luminosity regime. Astron. Astrophys. 582, A88 (2015).

    Article  Google Scholar 

  30. 30.

    Sacchi, M. et al. The SEXTANTS beamline at SOLEIL: a new facility for elastic, inelastic and coherent scattering of soft X-rays. J. Phys. Conf. Ser. 425, 072018 (2013).

    Article  Google Scholar 

  31. 31.

    Doronin, M., Bertin, M., Michaut, X., Philippe, L. & Fillion, J.-H. Adsorption energies and prefactor determination for CH3OH adsorption on graphite. J. Chem. Phys. 143, 084703 (2015).

    ADS  Article  Google Scholar 

  32. 32.

    Naumkin, A. V., Kraut-Vass, A., Gaarenstroom, S. W. & Powell, C. J. NIST X-ray Photoelectron Spectroscopy Database (National Institute of Standards and Technology, 2012); https://srdata.nist.gov/xps/

  33. 33.

    Dupuy, R. et al. Spectrally-resolved UV photodesorption of CH4 in pure and layered ices. Astron. Astrophys. 603, A61 (2017).

    Article  Google Scholar 

  34. 34.

    Orient, O. J. & Strivastava, S. K. Electron impact ionisation of H2O, CO, CO2 and CH4. J. Phys. B 20, 3923–3936 (1987).

  35. 35.

    Straub, H. C., Renault, P., Lindsay, B. G., Smith, K. A. & Stebbings, R. F. Absolute partial cross sections for electron-impact ionization of H2, N2, and O2 from threshold to 1000 eV. Phys. Rev. A 54, 2146–2153 (1996).

  36. 36.

    Vegard, I. Struktur und Leuchtfähigkeit von festem Kohlenoxyd. Z. Phys. A Hadron Nucl. 61, 185–190 (1930).

    Google Scholar 

  37. 37.

    Fayolle, E. C. et al. CO ice photodesorption: a wavelength-dependent study. Astrophys. J. Lett. 739, L36 (2011).

    ADS  Article  Google Scholar 

  38. 38.

    Cruz-Diaz, G. A., Muñoz Caro, G. M., Chen, Y.-J. & Yih, T.-S. Vacuum-UV spectroscopy of interstellar ice analogs. I. Absorption cross-sections of polar-ice molecules. Astron. Astrophys. 562, A119 (2014).

    ADS  Article  Google Scholar 

  39. 39.

    Berkowitz, J. Atomic and Molecular Photoabsorption: Absolute Total Cross Sections (Academic, London, 2002).

  40. 40.

    Bertin, M. et al. UV photodesorption of interstellar CO ice analogues: from subsurface excitation to surface desorption. Phys. Chem. Chem. Phys. 14, 9929–9935 (2012).

    Article  Google Scholar 

  41. 41.

    Tîmneanu, N., Caleman, C., Hajdu, J. & van der Spoel, D. Auger electron cascades in water and ice. Chem. Phys. 299, 277–283 (2004).

    Article  Google Scholar 

  42. 42.

    Andersson, S. & van Dishoeck, E. F. Photodesorption of water ice. Astron. Astrophys. 491, 907–916 (2008).

    ADS  Article  Google Scholar 

  43. 43.

    DeSimone, A. J., Crowell, V. D., Sherrill, C. D. & Orlando, T. M. Mechanisms of H2O desorption from amorphous solid water by 157-nm irradiation: an experimental and theoretical study. J. Chem. Phys. 139, 164702 (2013).

    ADS  Article  Google Scholar 

  44. 44.

    Kimmel, G. A., Orlando, T. M., Vézina, C. & Sanche, L. Low-energy electron-stimulated production of molecular hydrogen from amorphous water ice. J. Chem. Phys. 101, 3282–3286 (1994).

    ADS  Article  Google Scholar 

  45. 45.

    Redlich, B., Zacharias, H., Meijer, G. & von Helden, G. Resonant infrared laser-induced desorption of methane condensed on NaCl(100): isotope mixture experiments. J. Chem. Phys. 124, 044704 (2006).

    ADS  Article  Google Scholar 

  46. 46.

    Hovington, P., Drouin, D. & Gauvin, R. CASINO: a new Monte Carlo code in C language for electron beam interaction—part I: description of the program. Scanning 19, 1–14 (2006).

    Article  Google Scholar 

  47. 47.

    Bethell, T. J. & Bergin, E. A. Photoelectric cross-sections of gas and dust in protoplanetary disks. Astrophys. J. 740, 7 (2011).

    ADS  Article  Google Scholar 

  48. 48.

    Dupuy, R. et al. The efficient photodesorption of nitric oxide (NO) ices: a laboratory astrophysics study. Astron. Astrophys. 606, L9 (2017).

    ADS  Article  Google Scholar 

  49. 49.

    Rab, C. et al. X-ray radiative transfer in protoplanetary disks: the role of dust and X-ray background fields. Astron. Astrophys. 609, A91 (2018).

    Article  Google Scholar 

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Acknowledgements

We thank C. Walsh for insights on X-rays in protoplanetary disks, D. Lis for comments on the paper and P. Marie-Jeanne for technical support. We acknowledge SOLEIL for the provision of synchrotron radiation facilities under project 20161406, and we thank N. Jaouen and the SEXTANTS team for their help on the beamline. This work was supported by the Programme National ‘Physique et Chimie du Milieu Interstellaire’ (PCMI) of CNRS/INSU with INC/INP co-funded by CEA and CNES. Financial support from LabEx MiChem, part of the French state funds managed by the ANR within the investissements d’avenir programme under reference ANR-11-10EX-0004-02, and by the Ile-de-France region DIM ACAV programme, is gratefully acknowledged. This work was done in collaboration with and through financial support from the European Organization for Nuclear Research (CERN) under collaboration agreement KE3324/TE.

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R.D. treated and analysed the data and wrote the manuscript. M.B., G.F., M.H. and J.-H.F. provided extensive input on the data analysis and the manuscript. J.-H.F., M.B., G.F. and R.D. initiated and supervised the project. J.-H.F., M.B. and P.J. designed the experimental set-up. G.F. contributed to the bibliographic work. All authors participated in the experimental runs at the SOLEIL synchrotron where the data were acquired.

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Correspondence to R. Dupuy.

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Dupuy, R., Bertin, M., Féraud, G. et al. X-ray photodesorption from water ice in protoplanetary disks and X-ray-dominated regions. Nat Astron 2, 796–801 (2018). https://doi.org/10.1038/s41550-018-0532-y

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