J/A+A/704/A233ivo://CDS.VizieR/J/A+A/704/A233CDSLi L.-H.Benetti S.Cai Y.-Z.Wang B.Pastorello A.Elias-Rosa N.,Reguitti A.Borsato L.Cappellaro E.Fiore A.Fraser M.Gromadzki M.,Harmanen J.Isern J.Kangas T.Kankare E.Lundqvist P.Mattila S.,Ochner P.Peng Z.-H.Reynolds T.M.Salmaso I.Srivastav S.,Stritzinger M.D.Tomasella L.Valerin G.Wang Z.-Y.Zhang J.-J.,Wu C.-Y.2026-03-02T06:25:50Z2025-12-12T09:32:54ZCDS support team

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

cds-question@unistra.frsupernovaeinfrared-photometryvisible-astronomybroad-band-photometryspectroscopyWe present optical observations of the Type IIb supernova (SN) 2017ckj, covering approximately 180 days after the explosion. Its early-time multi-band light curves display no clear evidence of a shock-cooling tail, resembling the behavior of SN2008ax. The V-band light curve exhibits a short rise time of about 5 days and reaches an absolute peak magnitude of M_V_=-18.58+/-0.17mag. The late-time multi-band light curves reveal a linear decline. We modelled the bolometric light curve of SN2017ckj to constrain the progenitor and the explosion parameters. We estimated a total mass of ^56^Ni synthesized by SN2017ckj of M_Ni_=0.21^+0.05^_-0.03_M_{sun}_, with a massive H-rich envelope of M_env_=0.4^+0.1^_-0.1_M_{sun}_. Both the ^56^Ni mass and the envelope mass of SN2017ckj are higher than those of typical SNe IIb, in agreement with its peculiar light curve evolution. The early-time spectra of SN2017ckj are dominated by a blue continuum, accompanied by narrow H_alpha_ and HeII emission lines. The earliest spectrum exhibits flash ionization features, from which we estimated a progenitor mass-loss rate of ~3.4x10^-4^M_{sun}_/yr. At later epochs, the spectra develop broad P-Cygni profiles and become increasingly similar to those of SNe IIb, especially SN2018gk. The late-time spectrum at around 139 days does not show a distinct decline in the strength of H_alpha_ emission profile, also indicating a relatively massive envelope of its progenitor. Aside from the H_alpha_ feature, the nebular spectrum exhibits prominent emission lines of OI, CaII, [CaII], and MgI], which are consistent with the prototypical SN1993J.2025A&A...704A.233Lhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/704/A233CatalogResearchIsServedByTAP VizieR generic servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/704/A233https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/704/A233http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/704/A233https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/704/A233https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/704/A233http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/704/A233GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapAssociated datahttps://cdsarc.cds.unistra.fr/assocdata/?obs_collection=J/A+A/704/A2333.322582951404819e-19 4.920466254354166e-19OpticalInfrareddefaultJ/A+A/704/A233/ugrizugriz light curvesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintDateDate'Y:M:D'time.epochnullableMJDModified Julian datedtime.epochdoublel_umagLimit flag on umagmeta.code.errorcharumag? u magnitudemagphot.mag;em.opt.Ufloatnullablee_umag? u magnitude errormagstat.error;phot.magfloatnullablegmag? g magnitudemagphot.mag;em.opt.Bfloatnullablee_gmag? g magnitude errormagstat.error;phot.magfloatnullablermag? r magnitudemagphot.mag;em.opt.Rfloatnullablee_rmag? r magnitude errormagstat.error;phot.magfloatnullableimag? i magnitudemagphot.mag;em.opt.Ifloatnullablee_imag? i magnitude errormagstat.error;phot.magfloatnullablezmag? z magnitudemagphot.mag;em.opt.Ifloatnullablee_zmag? z magnitude errormagstat.error;phot.magfloatnullableSourceSourcemeta.id;instrcharJ/A+A/704/A233/bvBV light curvesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintDateDate'Y:M:D'time.epochnullableMJDModified Julian datedtime.epochdoublel_BmagLimit flag on Bmagmeta.code.errorcharBmagB magnitudemagphot.mag;em.opt.Bfloate_BmagB magnitude errormagstat.error;phot.magfloatl_VmagLimit flag on Vmagmeta.code.errorcharVmagV magnitudemagphot.mag;em.opt.Vfloate_VmagV magnitude errormagstat.error;phot.magfloatSourceSourcemeta.id;instrcharJ/A+A/704/A233/listList of spectrarecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNxNumber of pixels along X-axismeta.numberintNy? Number of pixels along Y-axismeta.numberintnullableObs.dateObservation datestime.epoch;obsnullableblambdaLower value of wavelength interval0.1nmem.wlfloatBlambdaUpper value of wavelength interval0.1nmem.wldoubledlambdaWavelength resolution0.1nmspect.resolutiondoublesizeSize of FITS fileKibytephys.size;meta.fitsintspShow the spectrummeta.ref.urlcharFileNameName of FITS file, in subdirectory fitsmeta.id;meta.fitscharTitleTitle of the FITS filemeta.title;meta.fitscharAssocDataAssociated Data web pagemeta.ref.urlchar