J/A+A/584/A12ivo://CDS.VizieR/J/A+A/584/A12doi:10.26093/cds/vizier.35840012CDSMunari U.Jurdana-Sepic R.Ochner P.Cherini G.2017-06-22T14:28:27Z2015-11-13T08:17:41ZCDS support team

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

cds-question@unistra.frnovaecataclysmic-variable-starsspectroscopyWe have monitored the 2014 superoutburst of the WZ Sge-type transient PNV J03093063+2638031 for more than four months, from V=11.0 maximum brightness down to V=18.4mag, close to quiescence value, by obtaining BV Rc Ic photometry and low resolution fluxed spectroscopy. The evolution was normal and no late-time 'echo' outbursts were observed. The absolute integrated flux of emission lines kept declining along the superoutburst, and their increasing contrast with the underlying continuum was simply the result of the faster decline of the continuum compared to the emission lines. Inspection of historical Harvard plates covering the 1899-1981 period did not reveal previous outbursts, neither 'normal' nor 'super'. We discovered an extended emission nebula (radius ~1-arcmin) around PNV J03093063+2638031, that became visible for a few months as the result of photo-ionization from the superoutburst of the central star. The nebula is not present on Palomar I and II sky survey images and it quickly disappeared when the outburst was over. From the rate at which the ionization front swept through the nebula, we derive a distance of ~120pc to the system. The nebula is density bounded with an outer radius of 0.03pc, and the absolute magnitude of the central star in quiescence is M_V_~14.2mag. The electron density in the nebula is estimated to be 10^5^cm^-3^ from the observed recombination time scale. Given the considerable substructures seen across the nebula, a low filling factor is inferred. Similar nebulae have not been reported for other WZ Sge objects and the challenges posed to models are considered.2015A&A...584A..12Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/584/A12CatalogResearchIsServedByTAP VizieR generic servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/584/A12https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/584/A12http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/584/A12https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/584/A12https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/584/A12http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/584/A12GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/A+A/584/A12/20141223PNV J03093063+2638031 spectrum on 2014/12/23recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintlambdaWavelength0.1nmem.wldoublelogFluxFlux (in erg/cm^2^/s/{AA})log(10mW.m**-2.nm**-1)phot.fluxdoubleJ/A+A/584/A12/20141030PNV J03093063+2638031 spectrum on 2014/10/30recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintlambdaWavelength0.1nmem.wldoublelogFluxFlux (in erg/cm^2^/s/{AA})log(10mW.m**-2.nm**-1)phot.fluxdoubleJ/A+A/584/A12/table4Upper limits to the magnitude of PNV J03093063+2638031 on the 332 Harvard plates we inspected looking for previous unrecorded outburstsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintJDJulian datetime.epochcharObsObservation datetime.epoch;obsnullableSPlatePlate seriesobs.fieldcharNPlatePlate numberobs.fieldintmaglimLimiting magnitude of the platemagphot.magfloatJ/A+A/584/A12/20141102PNV J03093063+2638031 spectrum on 2014/11/02recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintlambdaWavelength0.1nmem.wldoublelogFluxFlux (in erg/cm^2^/s/{AA})log(10mW.m**-2.nm**-1)phot.fluxdoubleJ/A+A/584/A12/20141123PNV J03093063+2638031 spectrum on 2014/11/23recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintlambdaWavelength0.1nmem.wldoublelogFluxFlux (in erg/cm^2^/s/{AA})log(10mW.m**-2.nm**-1)phot.fluxdouble