Abstract
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⊙ ≲ MWD ≲ 1.3 M⊙. If the accretion occurs at a constant rate, Macc ≃ 3.6+4.7 -2.5 ×10-7 M⊙ 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.
Original language | English |
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Article number | 145 |
Journal | Astrophysical Journal |
Volume | 818 |
Issue number | 2 |
DOIs | |
Publication status | Published - 20 Feb 2016 |
Keywords
- galaxies: individual (LMC)
- novae, cataclysmic variables
- stars: individual (Nova LMC 2009a, Nova LMC 1971b)
- white dwarfs