J/ApJ/900/11ivo://CDS.VizieR/J/ApJ/900/11doi:10.26093/cds/vizier.19000011CDSWeil K.E.Fesen R.A.Patnaude D.J.Milisavljevic D.2022-03-14T07:13:15Z2021-11-12T06:42:17ZCDS support team

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

cds-question@unistra.frsupernovaevisible-astronomyspectroscopySN 2017eaw, the tenth supernova observed in NGC6946, was a normal Type II-P supernova with an estimated 11-13M{sun} red supergiant progenitor. Here we present nebular-phase spectra of SN 2017eaw at +545 and +900days post-max, extending approximately 50-400days past the epochs of previously published spectra. While the +545day spectrum is similar to spectra taken between days +400 and +493, the +900day spectrum shows dramatic changes both in spectral features and emission-line profiles. The H{alpha} emission is flat-topped and boxlike with sharp blue and red profile velocities of ~-8000 and +7500km/s. These late-time spectral changes indicate strong circumstellar interaction with a mass-loss shell, expelled ~1700yr before explosion. SN 2017eaw's +900day spectrum is similar to those seen for SN2004et and SN2013ej observed 2-3yr after explosion. We discuss the importance of late-time monitoring of bright SNeII-P and the nature of presupernova mass-loss events for SNII-P evolution.2020ApJ...900...11Whttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/900/11CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/MNRAS/372/1315 : UBVRI photometry of SN 2004et (Sahu+, 2006)J/MNRAS/395/1409 : Type II-P SN progenitor constraints (Smartt+, 2009)J/A+A/553/A104 : LHA 120-N49 supernova remnant maps (Melnik+, 2013)J/MNRAS/438/L101 : First month on SN 2013ej (Valenti+, 2014)J/MNRAS/449/1876 : Photometric observations of SN PTF11iqb (Smith+, 2015)J/MNRAS/459/3939 : Type II supernova light curves (Valenti+, 2016)J/AJ/156/18 : APOGEE DR14 Binary comp. evolved stars (Price-Whelan+, 2018)J/ApJ/885/43 : UBVRI & ugriz photo. of supernova SN 2017gmr (Andrews+,2019)J/MNRAS/487/832 : BVRI photometry of the Type II-P SN 2017eaw (Buta+, 2019)J/ApJ/875/85 : Optical search SNRs in NGC6946 with WIYN & GMOS (Long+,2019)J/ApJ/875/136 : BVRI, spectra & IR obs. type II-P SN2017eaw (Van Dyk+, 2019)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/900/11https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/900/11http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/900/11https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/900/11https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/900/11http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/900/11GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/ApJ/900/11/figure1Combined table from original tablesFluxFlux in erg/cm2/s/Angstrom (1)phot.flux.density;em.optdoublerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintTimeTime after explosiondtime.epochcharWaveRest Wavelength in Angstroms (1)0.1nmem.wldouble