Binary orbits as the driver of gamma-ray emission and mass ejection in classical novae
Artikel i vetenskaplig tidskrift, 2014
Classical novae are the most common astrophysical thermonuclear explosions, occurring on the surfaces of white dwarf stars accreting gas from companions in binary star systems(1). 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 energy(2), prolonged optically thick winds(3) or binary interaction with the nova envelope(4). Classical novae are now routinely detected at gigaelectronvolt gamma-ray wavelengths(5), suggesting that relativistic particles are accelerated by strong shocks in the ejecta. Here we report high-resolution radio imaging of the gamma-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 motion(6,7). 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 gamma-ray production. Binary shaping of the nova ejecta and associated internal shocks are expected to be widespread among novae(8), explaining why many novae are gamma-ray emitters(5).
Författare
L. Chomiuk
Michigan State University
Justin D. Linford
Michigan State University
Jun Yang
Chalmers, Rymd- och geovetenskap, Onsala rymdobservatorium
T. J. O'Brien
University of Manchester
Z. Paragi
Joint Institute for VLBI in Europe (JIVE)
A. J. Mioduszewski
National Radio Astronomy Observatory
R. J. Beswick
University of Manchester
C. C. Cheung
Naval Research Laboratory
K. Mukai
NASA Goddard Space Flight Center
University of Maryland
T. Nelson
University of Minnesota
Varm Ribeiro
University of Cape Town
M. P. Rupen
National Research Council Canada
National Radio Astronomy Observatory
J. L. Sokoloski
Columbia University
J. Weston
Columbia University
Y. Zheng
Columbia University
M. F. Bode
Liverpool John Moores University
S. Eyres
University of Central Lancashire
N. Roy
Max-Planck-Gesellschaft
G. Taylor
University of New Mexico
Nature
0028-0836 (ISSN) 1476-4687 (eISSN)
Vol. 514 7522 339-+Novel EXplorations Pushing Robust e-VLBI Services (NEXPReS)
Europeiska kommissionen (EU) (EC/FP7/261525), 2010-07-01 -- 2013-06-30.
Advanced Radio Astronomy in Europe (RADIONET3)
Europeiska kommissionen (EU) (EC/FP7/283393), 2012-01-01 -- 2015-12-31.
Ämneskategorier
Astronomi, astrofysik och kosmologi
DOI
10.1038/nature13773