J/ApJ/881/9ivo://CDS.VizieR/J/ApJ/881/9doi:10.26093/cds/vizier.18810009CDSHoward+Howard W.S.Corbett H.Law N.M.Ratzloff J.K.Glazier A.,Fors O.del Ser D.Haislip J.2022-09-06T13:56:58Z2021-01-06T12:48:52ZCDS support team

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

cds-question@unistra.frstellar-flaressurveysstellar-spectral-typesvisible-astronomyWe search for superflares from 4068 cool stars in 2+yr of Evryscope photometry, focusing on those with high-cadence data from both Evryscope and the Transiting Exoplanet Survey Satellite (TESS). The Evryscope array of small telescopes observed 575 flares from 284 stars, with a median energy of 1034.0erg. Since 2016, Evryscope has enabled the detection of rare events from all stars observed by TESS through multi-year, high-cadence continuous observing. We report around twice the previous largest number of 1034erg high-cadence flares from nearby cool stars. We find eight flares with amplitudes of 3+g' magnitudes, with the largest reaching 5.6mag and releasing 1036.2erg. We observe a 1034erg superflare from TOI-455 (LTT1445), a mid-M with a rocky planet candidate. We measure the superflare rate per flare-star and quantify the average flaring of active stars as a function of spectral type, including superflare rates, flare frequency distributions, and typical flare amplitudes in g'. We confirm superflare morphology is broadly consistent with magnetic reconnection. We estimate starspot coverage necessary to produce superflares, and hypothesize maximum allowed superflare energies and waiting times between flares corresponding to 100% coverage of the stellar hemisphere. We observe decreased flaring at high Galactic latitudes. We explore the effects of superflares on ozone loss to planetary atmospheres: we observe one superflare with sufficient energy to photodissociate all ozone in an Earth-like atmosphere in one event. We find 17 stars that may deplete an Earth-like atmosphere via repeated flaring. Of the 1822 stars around which TESS may discover temperate rocky planets, we observe 14.6%{+/-}2% emit large flares.2019ApJ...881....9Hhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/881/9CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toI/337 : Gaia DR1 (Gaia Collaboration, 2016)I/345 : Gaia DR2 (Gaia Collaboration, 2018)IV/38 : TESS Input Catalog - v8.0 (TIC-8) (Stassun+, 2019)J/AJ/132/866 : New M dwarfs in solar neighborhood (Riaz+, 2006)J/AJ/134/2340 : Member. of Praesepe & Coma Berenices clusters (Kraus+,2007)J/AJ/136/1242 : LMC long-period variables from MACHO (Fraser+, 2008)J/AJ/135/785 : SDSS-DR5 low-mass star spectroscopic sample (West+, 2008)J/ApJ/767/95 : Stellar parameters of smallest KIC stars (Dressing+, 2013)J/ApJS/207/15 : M dwarf flare spectra (Kowalski+, 2013)J/MNRAS/443/2561 : CONCH-SHELL catalog of nearby M dwarfs (Gaidos+, 2014)J/AJ/147/146 : Spectroscopy of Tuc-Hor candidate members (Kraus+, 2014)J/ApJ/788/48 : X-ray through NIR photometry of NGC 2617 (Shappee+, 2014)J/ApJ/807/45 : Habitable planets orbiting M dwarfs (Dressing+, 2015)J/ApJ/804/64 : Empirical and model parameters of 183 M dwarfs (Mann+, 2015)J/ApJ/812/3 : MEarth mid-to-late M dwarfs rot. & kinematics (West+, 2015)J/ApJ/829/23 : Stellar flares from Q0-Q17 Kepler LCs (Davenport, 2016)J/MNRAS/463/1844 : M dwarfs rotation-activity relation (Stelzer+, 2016)J/A+A/600/A13 : HARPS M dwarf magnetic activity (Astudillo-Defru+, 2017)J/AJ/154/67 : HAZMAT II Low-mass stars GALEX UV obs. (Miles+, 2017)J/ApJ/851/91 : Statistical studies solar whitelight flares (Namekata+,2017)J/ApJ/834/85 : H{alpha} emission in nearby M dwarfs (Newton+, 2017)J/ApJS/232/26 : Catalog of Kepler flare stars (Van Doorsselaere+, 2017)J/ApJ/849/36 : Flaring activity of M dwarfs in Kepler field (Yang+, 2017)J/A+A/613/A25 : Radial velocity for Ross 128 (Bonfils+, 2018)J/AJ/155/180 : Catalog of cool dwarf targets for the TESS (Muirhead+, 2018)J/AJ/156/259 : Robo-AO detected close binaries in Gaia DR2 (Ziegler+, 2018)J/AJ/157/113 : TESS M-dwarf exoplanetary systems (Ballard, 2019)J/A+A/622/A133 : M45, M44 and M67 flare stars (Ilin+, 2019)J/ApJ/874/L8 : The TESS Habitable Zone Star Catalog (Kaltenegger+, 2019)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/881/9https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/881/9http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/881/9https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/881/9https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/881/9http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/881/9GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/881/9/table2 (Cool flare stars observed by evryscope in TESS sectors 1-6)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/881/9/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/881/9/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/881/9/table2?GETtext/xml+votable180.050000true71.6649264-27.87284420.005555555555555556Cone search capability for table J/ApJ/881/9/table1 (Individual flares observed by evryscope from cool stars in TESS sectors 1-6)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/881/9/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/881/9/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/881/9/table1?GETtext/xml+votable180.050000true98.8427786-57.62643750.0055555555555555566/16435 16438 16454-16455 16525 16561 16563 16622 16765 16987 16990 16993 17014 17055 17058 17066 17083 17121 17124 17131 17139 17202 17219 17288 17425 17511 17531 17597 17605-17606 17617 17640 17813 17816 17818 17822 20505 20507 20529 20540 20595 20618 20650 20661 21177 21180 21254 21260 21422 22202 22535 22603 22645 22760 22856-22857 22904 23047 23094 23100 23111 23442-23443 32789 32805 32822 32827 32868 32925 32930 32940 32953 32978 33029 33055 33064-33065 33075 33115 33118 33129-33130 33141 33144 33175 33193 33198 33226 33228 33235 33243 33255 33265-33266 33320 33365 33375 33377 33403 33449 33464-33465 33475 33482 33490 33493 33501 33522-33523 33531 33538 33548 33550 33552 33583 33588-33589 33594-33595 33613 33664 33666 33716 33792 33818 33829-33830 33834 33838-33839 33848-33849 33879 33882 33894 33904 33906 33912 33937 33996 34026 34062 34127 34140 34145 34159 34196 34198 34266 34292-34293 34305 34312 34377 34380 34439 34450 34483 34486 34592 34638 34680 34734 34742 34748 34776 34819 34830 34833 34851 34857 34900 34921 34942 34963 34976 34979 34984 34998 35053 35100 35131 35143 35147 35150 35154 35283 35287 35391-35392 35497 35517-35518 35531 35558-35559 35629 35640 35832 35860 35886-35887 35970 36003 36057 36146 36148 36152 36319 36401 36466 36492 36593 36614 36620 36660 37038 37041 37055 37102 37379 37389 37406 37416 37418 37442-37443 37449 37452 37481 37485 37508 37547 37552 37554 37613 38941 38948 38952 38970 38973 39046 39065 39107 39113 39439 39627 39630 45120 45126 45269 45323 45326 45336 45345 45355 45371 45374 45377 45389 45391 45428 45430 45433 45470-45471 45492 45503 45544 45852-45853 46020 46082 46087 46098 46148 46247 46344 46351 46406 46456 46544 46598 46620 46630-46631 46634 46675 46685 46698 46717-46718 46720 46723 46733 46784-46785 46803 46851 46856 47047 47050 48246 48261-48263 48286-48287 48404 48418-48419 48453 48455https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/881/9?format=asciiOpticaldefaultJ/ApJ/881/9/table2Cool flare stars observed by evryscope in TESS sectors 1-6recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintTICTESS Input Catalog identifiermeta.id;meta.mainlongprimaryRAJ2018[0.35/360] Right Ascension in decimal degrees (J2018)degpos.eq.ra;meta.mainDEJ2018[-85/8.9] Declination in decimal degrees (J2018)degpos.eq.dec;meta.mainSectorTESS sectorobs.fieldcharSimbadSimbad column added by the CDSmeta.ref.urlchar_RA.icrsRight ascension (ICRS) (computed by VizieR, not part of the original data. The format may include more digits than the original data because of internal accuracy requirements in VizieR and across other CDS services)degpos.eq.ranullableindexed_DE.icrsDeclination (ICRS) (computed by VizieR, not part of the original data. The format may include more digits than the original data because of internal accuracy requirements in VizieR and across other CDS services)degpos.eq.decnullableindexedFlares[1/24] Number of flares observed by Evryscopemeta.numberintNObs[5.2/100] Total continuous Evryscope observation time over 2 yearsdtime.epochfloatSFlares[0/288] Annual superflare rateyr**-1meta.numberfloate_SFlares[0/99] Lower uncertainty in SFlareyr**-1stat.errorfloatE_SFlares[3.5/91] Upper uncertainty in SFlareyr**-1stat.error;stat.maxfloatalpha[-0.86/-0.24]? The FFD parameter {alpha}stat.fit.paramfloatnullablebeta[6.6/27.8]? The FFD parameter {beta}stat.fit.paramfloatnullablelogE[31.6/35.7] mean bolometric flare energy; erglog(1e-07J)phys.energyfloatlogEmax[31.6/36.1] maximum bolometric flare energy; erglog(1e-07J)phys.energyfloatCon[0.1/3.6] Mean flare amplitude (contrast) (1)magsrc.var.amplitudefloatConmax[0.1/5.6] Maximum flare amplitude (contrast) (1)magsrc.var.amplitudefloatGLAT[-82.55/-7.03] Galactic latitudedegpos.galactic.latfloatTmag[7/18.4] TESS apparent magnitudemagphot.magfloatgmag[9.4/15] The g' band apparent magnitudemagphot.mag;em.opt.RfloatlogL[29.4/31.8] stellar quiescent luminosity in g'; erg/slog(1e-07W)phys.luminosityfloatgMAG[8.1/14] Absolute stellar g' band magnitudemagphys.magAbsfloatSpTEstimated photometric spectral typesrc.spTypecharJ/ApJ/881/9/table1Individual flares observed by evryscope from cool stars in TESS sectors 1-6SectorTESS sectorobs.fieldcharTICTESS Input Catalog identifiermeta.id;meta.mainlongFWHM[2/143] Flare Full Width at Half Maximumminspect.line.widthfloate_FWHM[2] Uncertainty in FWHMminstat.error;phys.angSizeintImp[0/8.26] Flare impulse; Amp/FWHMmin**-1meta.codefloate_Imp[0/6.18] Uncertainty in Impmin**-1stat.errorfloatgMAG[8/14.3] Absolute stellar g' band magnitudemagphys.magAbsfloatSpTEstimated photometric spectral typesrc.spTypecharSimbadSimbad column added by the CDSmeta.ref.urlchar_RAPosition from SIMBAD (right ascension part)degpos.eq.ra;meta.main_DEPosition from SIMBAD (declination part)degpos.eq.dec;meta.mainrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintMJDs[57399/58293] MJD of flare startdtime.epochdoubleMJDp[57399/58293] MDJ of flare peakdtime.epochdoubleMJDe[57399/58293] MDJ of flare enddtime.epochdoublelogE[31/36.1] log bolometric flare energy; erglog(1e-07J)phys.energyfloate_logE[29.4/35.4] Uncertainty in logElog(1e-07J)stat.errorfloatCon[0.1/5.6] Flare amplitude (contrast) in g' magnitudesmagsrc.var.amplitudefloate_Con[0/0.19] Uncertainty in Conmagstat.errorfloatAmp[0/84.3] Flare amplitude in fractional flux unitsmeta.unit;src.var.amplitude;arith.ratiofloate_Amp[0/0.16] Uncertainty in Ampstat.errorfloatlogL[29.3/31.8] log stellar quiescent luminosity in g'; erg/slog(1e-07W)phys.luminosityfloatED[0/100000] Equivalent duration in g'stime.durationinte_ED[0/18240] Uncertainty in EDsstat.errorint