J/ApJ/964/181ivo://CDS.VizieR/J/ApJ/964/181CDSHiramatsu D.Matsumoto T.Berger E.Ransome C.Villar V.A.Gomez S.,Cendes Y.De K.Bostroem K.A.Farah J.Howell D.A.McCully C.,Newsome M.Padilla Gonzalez E.Pellegrino C.Suzuki A.Terreran G.2026-08-20T12:09:50Z2026-08-20T12:41:09ZCDS support team

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

cds-question@unistra.frsupernovaephotometryvisible-astronomyspectroscopyWe present optical photometry and spectroscopy of the Type IIn supernova (SN) 2021qqp. Its unusual light curve is marked by a long precursor for ~300d, a rapid increase in brightness for ~60d, and then a sharp increase of ~1.6mag in only a few days to a first peak of Mr~-19.5mag. The light curve then declines rapidly until it rebrightens to a second distinct peak of Mr~-17.3mag centered at ~335d after the first peak. The spectra are dominated by Balmer lines with a complex morphology, including a narrow component with a width of ~1300km/s (first peak) and ~2500km/s (second peak) that we associate with the circumstellar medium (CSM) and a P Cygni component with an absorption velocity of ~8500km/s (first peak) and ~5600km/s (second peak) that we associate with the SN-CSM interaction shell. Using the luminosity and velocity evolution, we construct a flexible analytical model, finding two significant mass-loss episodes with peak mass loss rates of ~10 and ~5M_{sun}_/yr about 0.8 and 2yr before explosion, respectively, with a total CSM mass of ~2-4M_{sun}_. We show that the most recent mass-loss episode could explain the precursor for the year preceding the explosion. The SN ejecta mass is constrained to be ~5-30M_{sun}_ for an explosion energy of ~(3-10)x10^51^erg. We discuss eruptive massive stars (luminous blue variable, pulsational pair instability) and an extreme stellar merger with a compact object as possible progenitor channels.2024ApJ...964..181Hhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/964/181CatalogResearchIsServedByTAP VizieR generic servicerelated-toII/264 : ASAS Variable Stars in Southern hemisphere (Pojmanski+, 2002-2005)J/MNRAS/397/1177 : Swift-XRT observations of GRBs (Evans+, 2009)J/ApJS/183/214 : Arecibo Legacy Fast Alfa Survey VIII. (Martin+, 2009)J/AJ/142/170 : ALFALFA survey: {alpha}.40 HI source cat. (Haynes+, 2011)J/MNRAS/433/1312 : SN2009ip UBVRI, UVOT and JHK light curves (Fraser+, 2013)J/other/Nat/494.65 : SN 2010mc outburst before explosion (Ofek+, 2013)J/ApJ/763/L27 : RI light curves of the type IIn SN 2009ip (Prieto+, 2013)J/A+A/555/A10 : Light curves of 5 type IIn supernovae (Taddia+, 2013)J/ApJ/794/23 : Pan-STARRS1 transients optical photometry (Drout+, 2014)J/ApJ/787/163 : Photometric data for SN 2009ip (Graham+, 2014)J/ApJ/792/30 : NEOWISE magnitudes for near-Earth objects (Mainzer+, 2014)J/ApJ/789/104 : SNe IIn observations and properties (Ofek+, 2014)J/A+A/579/A40 : PESSTO catalog (Smartt+, 2015)J/A+A/594/A116 : HI4PI spectra and column density maps (HI4PI team+, 2016)J/MNRAS/459/3939 : Type II supernova light curves (Valenti+, 2016)J/A+A/605/A6 : Photometry of supernova iPTF13z (Nyholm+, 2017)J/ApJ/855/107 : PMAS Integral-field SN hosts COmpilation (Galbany+, 2018)J/ApJ/861/49 : ALFALFA extragalactic HI source catalog (Haynes+, 2018)J/ApJ/887/169 : UV-Opt light curves of the type Ic SN 2018gep (Ho+, 2019)J/A+A/637/A73 : Type IIn supernova photometry (Nyholm+, 2020)J/ApJ/913/143 : Optical LCs of the type Ic SN 2019stc (Gomez+, 2021)J/ApJS/255/29 : PTF core-collapse SN host-galaxies. I. (Schulze+, 2021)J/ApJ/907/99 : Pre-explosion light curve of 227 SNe (Strotjohann+, 2021)J/A+A/666/A79 : SN 2019zrk photometry and spectroscopy (Fransson+, 2022)J/ApJ/933/14 : LCs of type I superluminous SNe (Hosseinzadeh+, 2022)J/ApJ/938/73 : Follow-up phot. and sp. of 4 SNe Icn (Pellegrino+, 2022)J/ApJ/927/180 : Type Icn SN2021csp photometry & spectra (Perley+, 2022)J/ApJ/949/120 : Extragalactic fast blue transients from ZTF (Ho+, 2023)J/A+A/675/A195 : ZTF DR11 classif. in ZTF/4MOST sky (Sanchez-Saez+, 2023)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/964/181https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/964/181http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/964/181https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/964/181https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/964/181http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/964/181GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/ApJ/964/181/fig1aPhotometry 3{sigma} upper limits (binned every 30days)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintMJDModified Julian Date (JD-2400000.5)dtime.epochfloatBandBandmeta.code;instr.filtercharmagLim[18.6/23.7] Apparent upperlimit AB magnitudemagphot.mag;stat.maxfloatmagLim0[18.46/23.5] Dereddened upperlimit AB magnitude for the Milky Way extinctionmagphot.mag;stat.maxfloatJ/ApJ/964/181/fig1bPhotometry detectionsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintMJDModified Julian Date (JD-2400000.5)dtime.epochdoubleBandBandmeta.code;instr.filtercharSysMagnitude system ("AB"; or "Vega" for LCO B and V filters)meta.notecharmag[16.87/23.43] Apparent magnitude in Bandmagphot.magfloate_mag[0.01/0.4] The 1{sigma} uncertainty in magmagstat.error;phot.magfloatmag0[16.72/23.21] Dereddened magnitude in Band for the Milky Way extinctionmagphot.magfloatJ/ApJ/964/181/fig2Spectral time series of SN 2021qqprecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintMJDModified Julian Date (JD-2400000.5) (1)dtime.epochdoubleindexedTelTelescope ("MMT" or "Magellan")meta.id;instr.telcharInstInstrument ("Binospec" or "LDSS-3")meta.id;instrcharlambda[3702.38/10658.5] Observed wavelength in Angstroms0.1nmem.wldoubleFlux[-1.3e-16/3.3e-16] FluxcW.m**-2.nm**-1phot.fluxdoublee_Flux[2e-19/9.3e-17] Uncertainty in FluxcW.m**-2.nm**-1stat.error;phot.fluxdoubleFlux0Dereddened flux for the Milky Way extinctioncW.m**-2.nm**-1phot.fluxdouble