J/ApJ/954/35ivo://CDS.VizieR/J/ApJ/954/35doi:10.26093/cds/vizier/ba-xt-13CDSPellegrino C.Hiramatsu D.Arcavi I.Howell D.A.Bostroem K.A.,Brown P.J.Burke J.Elias-Rosa N.Itagaki K.Kaneda H.McCully C.,Modjaz M.Gonzalez E.P.Pritchard T.A.Yesmin N.2026-07-02T12:00:35Z2025-12-05T09:35:40ZCDS support team

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

cds-question@unistra.frsupernovaeultraviolet-photometryinfrared-photometryvisible-astronomybroad-band-photometryspectroscopyWe present photometric and spectroscopic observations of SN 2020bio, a double-peaked Type IIb supernova (SN) discovered within a day of explosion, primarily obtained by Las Cumbres Observatory and Swift. SN2020bio displays a rapid and long-lasting initial decline throughout the first week of its light curve, similarly to other well-studied Type IIb SNe. This early-time emission is thought to originate from the cooling of the extended outer hydrogen-rich (H-rich) envelope of the progenitor star that is shock heated by the SN explosion. We compare SN 2020bio to a sample of other double-peaked Type IIb SNe in order to investigate its progenitor properties. Analytical model fits to the early-time emission give progenitor radius (~100-1500R_{sun}_) and H-rich envelope mass (~0.01-0.5M_{sun}_) estimates that are consistent with other Type IIb SNe. However, SN 2020bio displays several peculiarities, including (1) weak H spectral features indicating a greater amount of mass loss than other Type IIb progenitors; (2) an underluminous secondary light-curve peak that implies a small amount of synthesized ^56^Ni (M_Ni_~0.02M_{sun}_); and (3) low-luminosity nebular [OI] and interaction-powered nebular features. These observations are more consistent with a lower-mass progenitor (M_ZAMS_~12M_{sun}_) that was stripped of most of its H-rich envelope before exploding. This study adds to the growing diversity in the observed properties of Type IIb SNe and their progenitors.2023ApJ...954...35Phttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/954/35CatalogResearchIsServedByTAP VizieR generic servicerelated-toII/183 : UBVRI Photometric Standards (Landolt 1992)I/322 : UCAC4 Catalogue (Zacharias+, 2012)VIII/77 : HI spectral properties of galaxies (Springob+, 2005)J/ApJ/702/226 : Swift/UVOT panchromatic obs. of SN 2008D (Modjaz+, 2009)J/ApJ/742/L18 : Follow-up photometry of the SN IIb PTF 11eon (Arcavi+, 2011)J/A+A/562/A17 : SN 2011dh - The first 100 days (Ergon+, 2014)J/ApJ/789/104 : SNe IIn observations and properties (Ofek+, 2014)J/A+A/573/A12 : SN1993J sp. 100-500 days post-explosion (Jerkstrand+, 2015)J/ApJ/827/90 : Spectroscopy of SNe Ib, IIb and Ic (Liu+, 2016)J/MNRAS/459/3939 : Type II supernova light curves (Valenti+, 2016)J/ApJ/883/147 : UV-NIR LCs of the H-stripped SN2016coi (Terreran+, 2019)J/ApJ/898/166 : UV to NIR obs. of SN 2019ehk (Jacobson-Galan+, 2020)J/ApJ/900/46 : UV, opt. & IR light curve of SN2019dge (Yao+, 2020)J/ApJ/912/46 : ZTF Type II supernovae with follow-up obs. (Bruch+, 2021)J/ApJ/907/99 : Pre-explosion LC of 227 Supernovae (Strotjohann+, 2021)J/ApJ/932/58 : LCs & sp. of SNe 2021gno & 2021inl (Jacobson-Galan+, 2022)http://www.wiserep.org/ : WISeREP homepagehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/954/35https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/954/35http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/954/35https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/954/35https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/954/35http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/954/35GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapUVOpticalInfrareddefaultJ/ApJ/954/35/table1UV and optical photometryrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintJDJulian Date of Observationdtime.epochdoubleFiltFiltermeta.id;instr.filtercharmag[13.46/20.92] Magnitude in Filt; either AB or Vega (1)magphot.magfloate_mag[0.01/0.3] Uncertainty in magmagstat.error;phot.magfloatTelSource/Telescope (2)meta.notecharJ/ApJ/954/35/table2Log of spectroscopic observationsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintDateDate of observation (UT)stime.epochnullableDays[1/201] Days since discoverytime.intervalintInstFacility/Instrumentmeta.id;instrcharExp[300/3600] Exposure timestime.duration;obs.exposureintlam1[3500/5700] Lower range of wavelength0.1nmem.wl;stat.minintlam2[7000/10000] Upper range of Wavelength0.1nmem.wl;stat.maxintFileFile name of the spectra in subdirectory "sp"; column added by CDSmeta.id;meta.filecharspInteractive spectrum plotmeta.ref.urlchar