Abstract
Classical novae are the most common astrophysical thermonuclear explosions, occurring on the surfaces of white dwarf stars accreting gas from companions in binary star systems1. Novae typically expel about 10−4 solar masses of material at velocities exceeding 1,000 kilometres per second. However, the mechanism of mass ejection in novae is poorly understood, and could be dominated by the impulsive flash of thermonuclear energy2, prolonged optically thick winds3 or binary interaction with the nova envelope4. Classical novae are now routinely detected at gigaelectronvolt γ-ray wavelengths5, suggesting that relativistic particles are accelerated by strong shocks in the ejecta. Here we report high-resolution radio imaging of the γ-ray-emitting nova V959 Mon. We find that its ejecta were shaped by the motion of the binary system: some gas was expelled rapidly along the poles as a wind from the white dwarf, while denser material drifted out along the equatorial plane, propelled by orbital motion6,7. At the interface between the equatorial and polar regions, we observe synchrotron emission indicative of shocks and relativistic particle acceleration, thereby pinpointing the location of γ-ray production. Binary shaping of the nova ejecta and associated internal shocks are expected to be widespread among novae8, explaining why many novae are γ-ray emitters5.
This is a preview of subscription content, access via your institution
Access options
Subscribe to this journal
Receive 51 print issues and online access
$199.00 per year
only $3.90 per issue
Rent or buy this article
Prices vary by article type
from$1.95
to$39.95
Prices may be subject to local taxes which are calculated during checkout



References
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)
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)
Kato, M. & Hachisu, I. Optically thick winds in nova outbursts. Astrophys. J. 437, 802–826 (1994)
MacDonald, J. The effect of a binary companion on a nova outburst. Mon. Not. R. Astron. Soc. 191, 933–949 (1980)
The Fermi-LAT collaboration. Fermi establishes classical novae as a distinct class of γ-ray sources. Science 345, 554–558 (2014)
Soker, N. & Livio, M. Interacting Winds and the shaping of planetary nebulae. Astrophys. J. 339, 268–278 (1989)
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)
Shankar, A., Livio, M. & Truran, J. W. The common envelope phase in classical novae: one-dimensional models. Astrophys. J. 374, 623–630 (1991)
Dubus, G. Gamma-ray binaries and related systems. Astron. Astrophys. Rev. 21, 64 (2013)
Abdo, A. A. et al. Gamma-ray emission concurrent with the nova in the symbiotic binary V407 Cygni. Science 329, 817–821 (2010)
Munari, U. et al. Photometric evolution, orbital modulation and progenitor of Nova Mon 2012. Mon. Not. R. Astron. Soc. 435, 771–781 (2013)
Hoard, D. W. et al. Nova-like cataclysmic variables in the infrared. Astrophys. J. 786, 68 (2014)
Seaquist, E. R. & Bode, M. F. in Classical Novae (eds Bode, M. F. & Evans, A. ) 141–166 (Cambridge Univ. Press, 2008)
Roy, N. et al. Radio studies of novae: a current status report and highlights of new results. Bull. Astron. Soc. India 40, 293–310 (2012)
Nelson, T. et al. X-ray and UV observations of Nova Mon 2012. Astron. Telegram 4321, (2012)
Seaquist, E. R. et al. A detailed study of the remnant of nova GK Persei and its environs. Astrophys. J. 344, 805–825 (1989)
O'Brien, T. J. et al. An asymmetric shock wave in the 2006 outburst of the recurrent nova RS Ophiuchi. Nature 442, 279–281 (2006)
Kantharia, N. G. et al. Rapid rise in the radio synchrotron emission from the recurrent nova system V745 Sco. Astron. Telegram 5962, (2014)
Ribeiro, V. A. R. M., Munari, U. & Valisa, P. Optical morphology, inclination, and expansion velocity of the ejected shell of Nova Monocerotis 2012. Astrophys. J. 768, 49 (2013)
Shore, S. N. et al. The spectroscopic evolution of the γ-ray emitting classical nova Nova Mon 2012. I. Implications for the ONe subclass of classical novae. Astron. Astrophys. 553, A123 (2013)
Page, K. L. et al. The 7.1 hr X-ray-ultraviolet-near-infrared period of the γ-ray classical Nova Monocerotis 2012. Astrophys. J. 768, L26 (2013)
Livio, M., Shankar, A., Burkert, A. & Truran, J. W. The common envelope phase in the outbursts of classical novae. Astrophys. J. 356, 250–254 (1990)
Lloyd, H. M., O’Brien, T. J. & Bode, M. F. Shaping of nova remnants by binary motion. Mon. Not. R. Astron. Soc. 284, 137–147 (1997)
Taylor, A. R., Hjellming, R. M., Seaquist, E. R. & Gehrz, R. D. Radio images of the expanding ejecta of nova QU Vulpeculae 1984. Nature 335, 235–238 (1988)
Eyres, S. P. S., Davis, R. J. & Bode, M. F. Nova Cygni 1992 (V1974 Cygni): MERLIN observations from 1992 to 1994. Mon. Not. R. Astron. Soc. 279, 249–256 (1996)
Heywood, I., O'Brien, T. J., Eyres, S. P. S., Bode, M. F. & Davis, R. J. V723 Cas (Nova Cassiopeiae 1995): MERLIN observations from 1996 to 2001. Mon. Not. R. Astron. Soc. 362, 469–474 (2005)
Passy, J. et al. Simulating the common envelope phase of a red giant using smoothed-particle hydrodynamics and uniform-grid codes. Astrophys. J. 744, 52 (2012)
Ivanova, N. et al. Common envelope evolution: where we stand and how we can move forward. Astron. Astrophys. Rev. 21, 59 (2013)
Cheung, C. C., Jean, P. & Shore, S. N. Fermi-LAT γ-ray observations of Nova Centauri 2013. Astron. Telegram 5649, (2013)
Chomiuk, L. et al. Dramatic brightening of Nova Mon 2012 at high radio frequencies. Astron. Telegram 4352, (2012)
Napier, P. J., Thompson, R. & Ekers, R. D. The Very Large Array—design and performance of a modern synthesis radio telescope. Proc. IEEE 71, 1295–1320 (1983)
McMullin, J. P., Waters, B., Schiebel, D., Young, W. & Golap, K. in Astronomical Data Analysis Software and Systems XVI (eds Shaw, R. A., Hill, F. & Bell, D. J. ) 127–130 (ASP Conf. Ser. 376, Astronomical Society of the Pacific, 2007)
Greisen, E. W. in Information Handling in Astronomy—Historical Vistas (ed. Heck, A. ) 109–125 (Astrophys. Space Sci. Library 285, Springer, 2003)
Shepherd, M. C., Pearson, T. J. & Taylor, G. B. DIFMAP: an interactive program for synthesis imaging. Bull. Am. Astron. Soc. 26, 987–989 (1994)
Briggs, D. S. High fidelity interferometric imaging: robust weighting and NNLS deconvolution. Bull. Am. Astron. Soc. 27, 1444 (1995)
Sault, R. J., Teuben, P. J. & Wright, M. C. H. in Astronomical Data Analysis Software and Systems IV (eds Shaw, R. A., Payne, H. E. & Hayes, J. J. E. ) 433–436 (ASP Conf. Ser. 77, Astronomical Society of the Pacific, 1995)
Fuhrmann, L. et al. Follow-up radio observations of Nova Mon 2012 at 10–142 GHz. Astron. Telegram 4376, (2012)
O’Brien, T. J. et al. Nova Mon 2012 resolved as a double radio source. Astron. Telegram 4408, (2012)
Acknowledgements
The National Radio Astronomy Observatory (NRAO) is a facility of the US National Science Foundation (NSF) operated under cooperative agreement by Associated Universities, Inc. The EVN is a joint facility of European, Chinese, South African and other radio astronomy institutes funded by their respective national research councils. The EVN and e-VLBI research infrastructures were supported by the European Commission Seventh Framework Programme (FP/2007-2013) under grant agreements nos 283393 (RadioNet3) and RI-261525 (NEXPReS). e-MERLIN is operated by The University of Manchester at Jodrell Bank Observatory on behalf of the Science and Technology Facilities Council. The SMA is a joint project between the Smithsonian Astrophysical Observatory and the Academia Sinica Institute of Astronomy and Astrophysics. Support for CARMA construction came from the Moore Foundation, the Norris Foundation, the McDonnell Foundation, the Associates of the California Institute of Technology, the University of Chicago, the states of California, Illinois and Maryland, and the NSF. Ongoing CARMA development and operations are supported by the NSF and by the CARMA partner universities. L.C. is a Jansky Fellow of the NRAO. This research received funding from NASA programmes DPR S-15633-Y and 10-FERMI10-C4-0060 (C.C.C.), NASA award NNX13AO91G (T.N.), NSF award AST-1211778 (J.L.S. and J.W.), the South African SKA Project (V.A.R.M.R.) and the Alexander von Humboldt Foundation (N.R.).
Author information
Authors and Affiliations
Contributions
L.C. wrote the text. L.C., J.D.L., J.Y., T.J.O., Z.P., A.J.M., C.C.C., R.J.B., T.N., Y.Z., J.W. and G.B.T. obtained and reduced the data. All authors contributed to the interpretation of the data and commented on the final manuscript.
Corresponding author
Ethics declarations
Competing interests
The authors declare no competing financial interests.
Extended data figures and tables
Extended Data Figure 1 Radio/millimetre spectral evolution of V959 Mon.
Measurements and 1σ uncertainties from select epochs are shown as black points. Power-law or broken power-law fits are overplotted as red lines (the function is chosen to minimize the reduced χ2 value). The best-fit spectral indices are listed in each panel, along with the break frequency (νb) in the case of broken power-law fits.
Extended Data Figure 2 Spectral index map from 2012 October 3 VLBA observations.
The spectral index is measured by comparing images at 1.6 and 5 GHz. Overlaid contours are from the 1.6 GHz Stokes I map. Contour levels are −0.08, 0.08, 0.13, 0.16, 0.23, 0.32 and 0.45 mJy per beam.
Extended Data Figure 3 The expansion of V959 Mon as a function of time.
Semi-major axis (a) and semi-minor axis (b), both in units of milliarcseconds. Measurements at four distinct frequencies are plotted in different colours (see key). Error bars from JMFIT (1σ) are so small that they are not visible. Linear fits are made to each frequency separately, and are plotted as coloured lines.
Extended Data Figure 4 Model fit to the radio/millimetre light curve of V959 Mon.
A simple model of thermal expanding ejecta roughly describes the light curve evolution at day ∼200 and later, and implies an ejected mass of few 10−5 solar masses. Error bars denote 1σ uncertainty.
Supplementary information
Supplementary Information
This file contains Supplementary Text and References. (PDF 118 kb)
Rights and permissions
About this article
Cite this article
Chomiuk, L., Linford, J., Yang, J. et al. Binary orbits as the driver of γ-ray emission and mass ejection in classical novae. Nature 514, 339–342 (2014). https://doi.org/10.1038/nature13773
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1038/nature13773
This article is cited by
-
Observations of galactic and extragalactic novae
The Astronomy and Astrophysics Review (2020)
-
Direct evidence for shock-powered optical emission in a nova
Nature Astronomy (2020)
-
Phenomenology of gamma-ray emitting binaries
Rendiconti Lincei. Scienze Fisiche e Naturali (2019)
-
Two-stage acceleration of interstellar ions driven by high-energy lepton plasma flows
Science China Physics, Mechanics & Astronomy (2015)
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.