J/ApJ/886/L14ivo://CDS.VizieR/J/ApJ/886/L14doi:10.26093/cds/vizier.18869014CDSGeballe T.R.Banerjee D.P.K.Evans A.Gehrz R.D.Woodward C.E.Mroz P.,Udalski A.Munari U.Starrfield S.Page K.L.Sokolovsky K.,Hambsch F.-J.Myers G.Aydi E.Buckley D.A.H.Walter F.Wagner R.M.2021-07-05T12:07:52Z2021-05-12T07:29:33ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frnovaeinfrared-astronomyspectroscopyFourteen years after its eruption as a classical nova (CN), V1047 Cen (Nova Cen 2005) began an unusual re-brightening in 2019 April. The amplitude of the brightening suggests that this is a dwarf nova (DN) eruption in a CN system. Very few CNe have had DN eruptions within decades of the main CN outburst. The 14yr separating the CN and DN eruptions of V1047 Cen is the shortest of all instances recorded thus far. Explaining this rapid succession of CN and DN outbursts in V1047 Cen may be challenging within the framework of standard theories for DN outbursts. Following a CN eruption, the mass accretion rate is believed to remain high (dM/dt~10^-8^M_{sun}_/yr) for a few centuries, due to the irradiation of the secondary star by the still-hot surface of the white dwarf. Thus a DN eruption is not expected to occur during this high mass accretion phase as DN outbursts, which result from thermal instabilities in the accretion disk, and arise during a regime of low mass accretion rate (dM/dt~10^-10^M_{sun}_/yr). Here we present near-infrared spectroscopy to show that the present outburst is most likely a DN eruption, and discuss the possible reasons for its early occurrence. Even if the present re-brightening is later shown to be due to a cause other than a DN outburst, the present study provides invaluable documentation of this unusual event.2019ApJ...886L..14Ghttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/886/L14CatalogResearchIsServedByTAP VizieR generic servicerelated-toB/vsx : AAVSO International Variable Star Index VSX (Watson+, 2006-2014)B/gemini : The Gemini Observation Log (CADC, 2001-)I/347 : Distances to 1.33 billion stars in Gaia DR2 (Bailer-Jones+, 2018)J/A+A/453/635 : Modelling Galactic Interstellar Extinction (Marshall+, 2006)J/AJ/141/121 : V446 Her V light curves (Honeycutt+, 2011)J/ApJS/197/31 : Swift X-ray obs. of classical novae. II. (Schwarz+, 2011)J/A+A/554/A123 : Near-IR catalog of novae in VVV survey area (Saito+, 2013)J/MNRAS/440/2036 : VPHAS+ survey synthetic colours (Drew+, 2014)J/ApJ/788/164 : Known Galactic classical novae (Pagnotta+, 2014)J/MNRAS/465/3011 : VVV high amplitude NIR var. stars (Contreras Pena+, 2017)J/A+A/647/A169 : VVV survey near-infrared colour catalog (Herpich+, 2021)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/886/L14https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/886/L14http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/886/L14https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/886/L14https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/886/L14http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/886/L14GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapInfrareddefaultJ/ApJ/886/L14/fig2The 0.9-2.5 micron spectra of V1047 Cen obtained on 2019 June 30/July 1 and 2019 August 1/2recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintDateDate code (1)meta.code;time.epochcharBand[JK] Band corresponding to spectral coverage (2)meta.code;instr.filtercharlambda[0.89/2.51] Wavelengthumem.wldoubleFlux[1.36e-14/6.76e-13] Observed fluxW.m**-2.um**-1phot.fluxdouble