Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Kelvin–Helmholtz instabilities as the source of inhomogeneous mixing in nova explosions

Abstract

Classical novae1,2 are thermonuclear explosions in binary stellar systems containing a white dwarf accreting material from a close companion star. They repeatedly eject 10−4–10−5 solar masses of nucleosynthetically enriched gas into the interstellar medium, recurring on intervals of decades to tens of millennia. They are probably the main sources3,4 of Galactic 15N, 17O and 13C. The origin of the large enhancements and inhomogeneous distribution of these species observed in high-resolution spectra5 of ejected nova shells has, however, remained unexplained for almost half a century6. Several mechanisms7, including mixing by diffusion8, shear9 or resonant gravity waves10, have been proposed in the framework of one-dimensional or two-dimensional simulations, but none has hitherto proven successful because convective mixing can only be modelled accurately in three dimensions. Here we report the results of a three-dimensional nuclear-hydrodynamic simulation of mixing at the core–envelope interface during nova outbursts. We show that buoyant fingering drives vortices from the Kelvin–Helmholtz instability, which inevitably enriches the accreted envelope with material from the outer white-dwarf core. Such mixing also naturally produces large-scale chemical inhomogeneities. Both the metallicity enhancement and the intrinsic dispersions in the abundances are consistent with the observed values.

This is a preview of subscription content, access via your institution

Access options

Buy article

Get time limited or full article access on ReadCube.

$32.00

All prices are NET prices.

Figure 1: Mixing driven by Kelvin–Helmholtz instabilities.
Figure 2: Cumulant distributions.

References

  1. Bode, M. F. & Evans, A. eds. Classical Novae 2nd edn (Cambridge Univ. Press, 2008)

    Book  Google Scholar 

  2. Hernanz, M. & José, J. eds. Classical Nova Explosions (AIP, 2002)

    Google Scholar 

  3. José, J., Hernanz, M. & Iliadis, C. Nucleosynthesis in classical novae. Nucl. Phys. A 777, 550–578 (2006)

    Article  ADS  Google Scholar 

  4. Starrfield, S., Iliadis, C. & Hix, W. R. in Classical Novae 2nd edn (eds Bode, M. F. & Evans, A. ) 77–101 (Cambridge Univ. Press, 2008)

    Book  Google Scholar 

  5. Gehrz, R. D., Truran, J. W., Williams, R. E. & Starrfield, S. Nucleosynthesis in classical novae and its contribution to the interstellar medium. Publ. Astron. Soc. Pacif. 110, 3–26 (1998)

    Article  ADS  Google Scholar 

  6. José, J. & Shore, S. N. in Classical Novae 2nd edn (eds Bode, M. F. & Evans, A. ) 121–140 (Cambridge Univ. Press, 2008)

    Book  Google Scholar 

  7. Shore, S. N., Livio, M. & van den Heuvel, E. P. J. Interacting Binaries (Springer, 1994)

    Book  Google Scholar 

  8. Prialnik, D. & Kovetz, A. The effect of diffusion on prenova evolution—CNO-enriched envelopes. Astrophys. J. 281, 367–374 (1984)

    Article  ADS  CAS  Google Scholar 

  9. Kutter, G. S. & Sparks, W. M. Stellar accretion of matter possessing angular momentum. Astrophys. J. 321, 386–393 (1987)

    Article  ADS  CAS  Google Scholar 

  10. Rosner, R., Alexakis, A., Young, Y.-N., Truran, J. W. & Hillebrandt, W. On the C/O enrichment of nova ejecta. Astrophys. J. 562, L177–L179 (2001)

    Article  ADS  CAS  Google Scholar 

  11. Porter, J. M., O’Brien, T. J. & Bode, M. F. On the asphericity of nova remnants caused by rotating white dwarf envelopes. Mon. Not. R. Astron. Soc. 296, 943–948 (1998)

    Article  ADS  Google Scholar 

  12. Vaytet, N. M. H., O’Brien, T. J. & Rushton, A. P. Evidence for ablated flows in the shell of the nova DQ Herculis. Mon. Not. R. Astron. Soc. 380, 175–180 (2007)

    Article  ADS  CAS  Google Scholar 

  13. Shore, S. N., Starrfield, S., Ake, T. B., III & Hauschildt, P. H. Spatially resolved spectra of V1974 Cygni (Nova Cygni 1992) with the Goddard High Resolution Spectrograph. Astrophys. J. 490, 393–400 (1997)

    Article  ADS  CAS  Google Scholar 

  14. Gehrz, R. D. in Classical Novae 2nd edn (eds Bode, M. F. & Evans, A. ) 167–193 (Cambridge Univ. Press, 2008)

    Book  Google Scholar 

  15. McLaughlin, D. B. The behaviour of absorption systems in spectra of novae. Annls Astrophys. 27, 450–461 (1964)

    ADS  Google Scholar 

  16. Starrfield, S., Truran, J. W., Sparks, W. M. & Kutter, G. S. CNO abundances and hydrodynamic models of the nova outburst. Astrophys. J. 176, 169–176 (1972)

    Article  ADS  CAS  Google Scholar 

  17. Glasner, S. A. & Livne, E. Convective hydrogen burning down a nova outburst. Astrophys. J. 445, L149–L151 (1995)

    Article  ADS  CAS  Google Scholar 

  18. Glasner, S. A., Livne, E. & Truran, J. W. Reactive flow in nova outbursts. Astrophys. J. 475, 754–762 (1997)

    Article  ADS  CAS  Google Scholar 

  19. Kercek, A., Hillebrandt, W. & Truran, J. W. Two-dimensional simulations of the thermonuclear runaway in an accreted atmosphere of a C+O white dwarf. Astron. Astrophys. 337, 379–392 (1998)

    ADS  CAS  Google Scholar 

  20. Glasner, S. A., Livne, E. & Truran, J. W. The sensitivity of multidimensional nova calculations to the outer boundary condition. Astrophys. J. 625, 347–350 (2005)

    Article  ADS  Google Scholar 

  21. Glasner, S. A., Livne, E. & Truran, J. W. Novae: the evolution from onset of convection to the runaway. Astrophys. J. 665, 1321–1333 (2007)

    Article  ADS  CAS  Google Scholar 

  22. Casanova, J., José, J., García-Berro, E., Calder, A. & Shore, S. N. On mixing at the core–envelope interface during classical nova outbursts. Astron. Astrophys. 513, L5 (2010)

    Article  ADS  Google Scholar 

  23. Casanova, J., José, J., García-Berro, E., Calder, A. & Shore, S. N. Mixing in classical novae: a 2-D sensitivity study. Astron. Astrophys. 527, A5 (2011)

    Article  ADS  Google Scholar 

  24. Kercek, A., Hillebrandt, W. & Truran, J. W. Three-dimensional simulations of classical novae. Astron. Astrophys. 345, 831–840 (1999)

    ADS  CAS  Google Scholar 

  25. Arnett, D., Meakin, C. & Young, P. A. Turbulent convection in stellar interiors. II. The velocity field. Astrophys. J. 690, 1715–1729 (2009)

    Article  ADS  Google Scholar 

  26. Pope, S. B. Turbulent Flows (Cambridge Univ. Press, 2000)

    Book  Google Scholar 

  27. Shore, S. N. Astrophysical Hydrodynamics: An Introduction (Wiley, 2007)

    Book  Google Scholar 

  28. Fryxell, B. A. & Woosley, S. E. Finite propagation time in multidimensional thermonuclear runaways. Astrophys. J. 261, 332–336 (1982)

    Article  ADS  CAS  Google Scholar 

  29. Fryxell, B. et al. FLASH: an adaptive mesh hydrodynamics code for modeling astrophysical thermonuclear flashes. Astrophys. J. 131 (Suppl.). 273–334 (2000)

    Article  CAS  Google Scholar 

  30. Zingale, M. et al. Mapping initial hydrostatic models in Godunov codes. Astrophys. J. 143 (Suppl.). 539–565 (2002)

    Article  Google Scholar 

Download references

Acknowledgements

The software used in this work was developed in part by the Department of Energy-supported Alliances Center for Astrophysical Thermonuclear Flashes at the University of Chicago. This work was partly supported by Spanish Ministerio de Educación y Ciencia grants, by the Agència de Gestió d'Ajuts Universitaris i de Recerca of the Generalitat de Catalunya, by the E.U. European Fund for Regional Development, and by the European Science Foundation EUROCORES Program EuroGENESIS. We also acknowledge the Barcelona Supercomputing Center for allocation of time at the MareNostrum supercomputer.

Author information

Authors and Affiliations

Authors

Contributions

All authors contributed equally to the results presented here.

Corresponding author

Correspondence to Jordi José.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Supplementary information

Supplementary Information

This file contains Supplementary Text, which describes Supplementary Movies 1 and 2. This file was replaced on 14 November 2011. (PDF 40 kb)

Supplementary Movie 1

This movie shows a two-dimensional slice of the time evolution of the 12C abundance, in logarithmic scale, at the core-envelope interface during a nova outburst on a 1 solar mass CO white dwarf that accretes solar composition matter. (MOV 25326 kb)

Supplementary Movie 2

This movie shows a two-dimensional slice of the time evolution of the 15O abundance, in linear scale, at the core-envelope interface during a nova outburst on a 1 solar mass CO white dwarf that accretes solar composition matter. (MOV 25362 kb)

PowerPoint slides

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Casanova, J., José, J., García-Berro, E. et al. Kelvin–Helmholtz instabilities as the source of inhomogeneous mixing in nova explosions. Nature 478, 490–492 (2011). https://doi.org/10.1038/nature10520

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nature10520

This article is cited by

Comments

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.

Search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing