Pan-chromatic observations of the recurrent Nova LMC 2009a (LMC 1971b)

• Verfasst von: Bode, Michael F. [VerfasserIn]
• Verfasst von: Krautter, Joachim [VerfasserIn]
• Titel: Pan-chromatic observations of the recurrent Nova LMC 2009a (LMC 1971b)
• Verf.angabe: M.F. Bode, M.J. Darnley, A.P. Beardmore, J.P. Osborne, K.L. Page, F.M. Walter, J. Krautter, A. Melandri, J.-U. Ness, T.J. O'Brien, M. Orio, G.J. Schwarz, M.M. Shara, and S. Starrfield
• Fussnoten: Gesehen am 13.10.2017
• Titel Quelle: Enthalten in: De.arxiv.org
• Jahr Quelle: 2016
• Band/Heft Quelle: (2016) Artikel-Nummer 1601.00474, 20 Seiten
• Datenträger: Online-Ressource
• Sprache: eng
• K10plus-PPN: 1564382346

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 and X-ray observations from 9 days to almost 1 year post-outburst. We find $M_V = -8.4\pm0.8_{\mathrm{r}}\pm0.7_{\mathrm{s}}$ and expansion velocities between 1000 and 4000 km s$^{-1}$. Coronal line emission before day 9 indicates shocks in the ejecta. Strengthening of He II $\lambda$4686 preceded the emergence of the Super-Soft Source (SSS) in X-rays at $\sim63-70$ 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 $1.1 \mathrm{M}_\odot \lesssim M_{\rm WD} \lesssim 1.3 \mathrm{M}_\odot$. If the accretion occurs at constant rate, $\dot{\it{M}}_{\rm acc} \simeq 3.6^{+4.7}_{-2.5} \times 10^{-7} \mathrm{M}_\odot$ 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.