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PAN-CHROMATIC OBSERVATIONS OF THE RECURRENT NOVA LMC 2009a (LMC 1971b)

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journal contribution
posted on 19.04.2016, 11:41 by M. F. Bode, M. J. Darnley, Andrew Paul Beardmore, Julian Paul Osborne, Kim L. Page, F. M. Walter, J. Krautter, A. Melandri, J.-U. Ness, T. J. O'Brien, M. Orio, G. J. Schwarz, M. M. Shara, S. Starrfield
Nova LMC 2009a is confirmed as a recurrent nova (RN) from positional coincidence with nova LMC 1971b. The observational data set is one of the most comprehensive for any Galactic or extragalactic RN: optical and near-IR photometry from outburst until over 6 years later; optical spectra for the first 6 months, and Swift satellite ultraviolet (UV) and X-ray observations from 9 days to almost 1 year post-outburst. We find MV = −8.4 ± 0.8r ± 0.7s and expansion velocities between 1000 and 4000 km s−1. Coronal line emission before day 9 indicates shocks in the ejecta. Strengthening of He iiλ4686 preceded the emergence of the super-soft source (SSS) in X-rays at ~63–70 days, which was initially very variable. Periodic modulations, P = 1.2 days, most probably orbital in nature, were evident in the UV and optical from day 43. Subsequently, the SSS shows an oscillation with the same period but with a delay of 0.28P. The progenitor system has been identified; the secondary is most likely a sub-giant feeding a luminous accretion disk. Properties of the SSS infer a white dwarf (WD) mass 1.1 M⊙ lesssim MWD lesssim 1.3 M⊙. If the accretion occurs at a constant rate, ${\dot{M}}_{{\rm{acc}}}\simeq {3.6}_{-2.5}^{+4.7}\times {10}^{-7}\;{M}_{\odot }$ yr−1 is needed, consistent with nova models for an inter-eruption interval of 38 years, low outburst amplitude, progenitor position in the color–magnitude diagram, and spectral energy distribution at quiescence. We note striking similarities between LMC 2009a and the Galactic nova KT Eri, suggesting that KT Eri is a candidate RN.

History

Citation

The Astrophysical Journal, 2016, 818, 145

Author affiliation

/Organisation/COLLEGE OF SCIENCE AND ENGINEERING/Department of Physics and Astronomy

Version

VoR (Version of Record)

Published in

The Astrophysical Journal

Publisher

IOP Publishing, American Astronomical Society

issn

0004-637X

eissn

1538-4357

Acceptance date

28/12/2015

Copyright date

2016

Available date

19/04/2016

Publisher version

http://iopscience.iop.org/article/10.3847/0004-637X/818/2/145/

Language

en