J/ApJ/851/91ivo://CDS.VizieR/J/ApJ/851/91doi:10.26093/cds/vizier.18510091CDSNamekata K.Sakaue T.Watanabe K.Asai A.Maehara H.Notsu Y.,Notsu S.Honda S.Ishii T.T.Ikuta K.Nogami D.Shibata K.2018-10-22T13:14:18Z2018-09-10T12:58:00ZCDS support team

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

cds-question@unistra.frstellar-flaresmagnetic-fieldsthe-sunRecently, many superflares on solar-type stars have been discovered as white- light flares (WLFs). The statistical study found a correlation between their energies (E) and durations ({tau}): {tau}{propto}E^0.39^, similar to those of solar hard/soft X-ray flares, {tau}{propto}E^0.2-0.33^. This indicates a universal mechanism of energy release on solar and stellar flares, i.e., magnetic reconnection. We here carried out statistical research on 50 solar WLFs observed with Solar Dynamics Observatory/HMI and examined the correlation between the energies and durations. As a result, the E-{tau} relation on solar WLFs ({tau}{propto}E^0.38^) is quite similar to that on stellar superflares ({tau}{propto}E^0.39^). However, the durations of stellar superflares are one order of magnitude shorter than those expected from solar WLFs. We present the following two interpretations for the discrepancy: (1) in solar flares, the cooling timescale of WLFs may be longer than the reconnection one, and the decay time of solar WLFs can be elongated by the cooling effect; (2) the distribution can be understood by applying a scaling law ({tau}{propto}E^1/3^B^-5/3^) derived from the magnetic reconnection theory. In the latter case, the observed superflares are expected to have 2-4 times stronger magnetic field strength than solar flares.2017ApJ...851...91Nhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/851/91CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/A+A/327/1114 : Optical flares on EV Lac in 1967-1977 (Leto+ 1997)J/AJ/141/50 : White-light flares on cool stars (Walkowicz+, 2011)J/ApJ/743/48 : Stellar rotation periods & X-ray luminosities (Wright+, 2011)J/ApJ/757/94 : Solar flares observed with GOES and AIA (Aschwanden, 2012)J/other/Nat/485.478 : Superflares on solar-type stars (Maehara+, 2012)J/ApJS/209/5 : Superflares of Kepler stars. I. (Shibayama+, 2013)J/ApJ/814/35 : Flare events in M dwarf of M37 (Chang+, 2015)J/ApJ/818/43 : Stellar surface gravity measures of KIC stars (Bastien+, 2016)J/ApJ/832/27 : Global energetics of solar flares. III. (Aschwanden+, 2016)J/ApJ/833/284 : Quasi-periodic pulsations in solar flares (Inglis+, 2016)J/ApJS/224/37 : White-light flares on close binaries from Kepler (Gao+, 2016)J/ApJS/229/30 : Revised properties of Q1-17 Kepler targets (Mathur+, 2017)J/ApJS/232/26 : Catalog of Kepler flare stars (Van Doorsselaere+, 2017)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/851/91https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/851/91http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/851/91https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/851/91https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/851/91http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/851/91GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapdefaultJ/ApJ/851/91/table3Physical parameters of flares with the Hinode/ Solar Optical Telescope (SOT)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSeq[2/41] Flare sequential running numbermeta.recordintobsHinode/SOT Flare peak timestime.epoch;stat.maxnullableEc[5/31.6] Flare energy corrected values for limb darkening1e+29ergphys.energyfloatt-HMI[2/2.8] Decay time of the HMI flaremintime;arith.difffloatt-red[1.9/3.2] Observed e-folding decay time w/ SOT/Red continuummintime;arith.difffloatt-green[2/3.2] Observed e-folding decay time w/ SOT/Green continuummintime;arith.difffloatt-blue[0.9/3.3] Observed e-folding decay time w/ SOT/Blue continuummintime;arith.difffloatJ/ApJ/851/91/flaresPhysical parameters and detailed observations of flares (tables 1 and 2)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHDisplay data from the Hinode/Solar Optical Telescope (table 3)meta.ref.urlcharSeqFlare sequential running numbermeta.record;meta.mainintprimaryObsFlare peak date of the GOES soft X-ray fluxsphot.flux;em.X-ray;stat.maxnullableClassGOES class (M1.0 to X2.8)src.classcharLoc-EW[-940/950] Event location, EWarcsecmeta.noteintLoc-NS[-410/560] Event location, NSarcsecmeta.noteintE[0.6/66.1] Flare energy radiated in the white light, in 10+29erg units1e+22Jphys.energyfloatEc[1.7/73] Flare energy corrected values for limb darkening, in 10+29erg units1e+22Jphys.energyfloate_E[0.4/13] Uncertainty on E or Ec1e+22Jstat.errorfloatF[1.1/40] Total counts of the white-light flares, data numbers100000countphot.countfloatFc[2.7/71.1] Total counts corrected values for limb darkening100000countphot.countfloate_F[0.1/3.5] Uncertainty in F or Fc100000countstat.errorfloatt-decay[0.9/14.1] E-folding decay timemintime;arith.difffloate_t-decay[0/1.5] Uncertainty in t-decayminstat.errorfloatt-HXR[0.03/8.5] Decay time of the HXR flare, 30-80keVmintime;arith.difffloatFc/Fsun[0.6/18.4] flare count to solar ratio, ppmphot.count;arith.ratiofloatB-est[42.4/126] Estimated magnetic field strength, gauss (1)0.0001Tphys.magField;phys.atmol.collStrengthfloatB-obs[3.2/137] Observed magnetic field strength, gauss (2)0.0001Tphys.magField;phys.atmol.collStrengthfloatL-est[1.3/6] Estimated loop length (1)1e+09cmsrc.morph.scLengthfloatL-obs[1/6] Observed loop length (2)1e+09cmsrc.morph.scLengthfloatstStart date of white-light flare (3)stime.startnullableendEnd date of white-light flare (3)stime.endnullableArea[10/70] HXR Area (4)%phys.areaintDetectorsRHESSI detector number(s) used.meta.id;instrchar