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The expanding fireball of Nova Delphini 2013

Schaefer, G. H. and Becker, J. (2014) The expanding fireball of Nova Delphini 2013. Nature, 515 (7526). pp. 234-236. ISSN 0028-0836.

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A classical nova occurs when material accreting onto the surface of a white dwarf in a close binary system ignites in a thermonuclear runaway. Complex structures observed in the ejecta at late stages could result from interactions with the companion during the common-envelope phase. Alternatively, the explosion could be intrinsically bipolar, resulting from a localized ignition on the surface of the white dwarf or as a consequence of rotational distortion. Studying the structure of novae during the earliest phases is challenging because of the high spatial resolution needed to measure their small sizes. Here we report near-infrared interferometric measurements of the angular size of Nova Delphini 2013, starting one day after the explosion and continuing with extensive time coverage during the first 43 days. Changes in the apparent expansion rate can be explained by an explosion model consisting of an optically thick core surrounded by a diffuse envelope. The optical depth of the ejected material changes as it expands. We detect an ellipticity in the light distribution, suggesting a prolate or bipolar structure that develops as early as the second day. Combining the angular expansion rate with radial velocity measurements, we derive a geometric distance to the nova of 4.54 ± 0.59 kiloparsecs from the Sun.

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Becker, J.0000-0002-7733-4522
Additional Information:© 2014 Macmillan Publishers Limited. Received 13 May 2014; Accepted 03 September 2014; Published online 26 October 2014. We acknowledge the variable star observations from the AAVSO International Database contributed by observers worldwide and used in this research. We thank O. Garde and other members of the Astronomical Ring for Access to Spectroscopy for use of their archive of Nova Del 2013 spectra. We thank G. J. Schwarz, S. N. Shore, and F. M. Walter for discussions that helped us to interpret the nova observations. This material is based upon work supported by the National Science Foundation under grant number AST-1009080. The CHARA Array is funded by the National Science Foundation through NSF grants AST 0908253 and AST 1211129, and by Georgia State University through the College of Arts and Sciences. This publication made use of data products from the Two Micron All Sky Survey, which is a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center/California Institute of Technology, funded by the National Aeronautics and Space Administration and the National Science Foundation. Author Contributions: Observations with the CHARA Array were originally proposed by B.K. and D.R.G. Modelling and interpreting the angular expansion curve and asymmetries were done by G.H.S., D.R.G., B.K., T.t.B., O.C., I.T.-B. and S.T.R. The CHARA data were reduced by T.t.B., J.D.M., O.C., I.T.-B., D.M., V.M., C.D.F., N.S. and G.H.S. The observations were planned and conducted by C.D.F., N.S., N.V., B.K., D.R.G., T.B., G.H.S., D.M., A.M., N.N., P.S., M.I., V.M., P.T., J.J., N.D.R., R.M.R., G.v.B., K.v.B. and R.T.Z. Observational setup and technical support were provided by J.S., L.S., N.H.T. and X.C. Administrative oversight and access to CHARA were provided by H.A.M. and T.t.B. Reconstructing and interpreting the nova images were done by G.H.S., F.B., J.D.M. and B.K. Infrared magnitudes derived from CHARA data were computed by N.S. and G.H.S. Infrared spectra were taken and reduced by D.P.K.B., N.M.A., V.J., P.S.M., J.B. and analysed by D.R.G. All authors discussed the results and commented on the manuscript.
Funding AgencyGrant Number
NSFAST 0908253
NSFAST 1211129
Georgia State University College of Arts and SciencesUNSPECIFIED
Issue or Number:7526
Record Number:CaltechAUTHORS:20141110-091157796
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:51483
Deposited By: Tony Diaz
Deposited On:10 Nov 2014 17:44
Last Modified:03 Oct 2019 07:33

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