J/ApJ/906/40ivo://CDS.VizieR/J/ApJ/906/40doi:10.26093/cds/vizier.19060040CDSGoodarzi H.Mehrabi A.Khosroshahi H. GHe H.2022-11-13T17:05:21Z2022-05-31T07:05:12ZCDS support team

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

cds-question@unistra.frf-starsstellar-radiistellar-massesmetallicityeffective-temperaturevisible-astronomyWe present an investigation of the magnetic activity and flare characteristics of the subgiant stars mostly from F and G spectral types and compare the results with the main-sequence (MS) stars. The light curve of 352 stars on the subgiant branch (SGB) from the Kepler mission is analyzed in order to infer stability, relative coverage, and contrast of the magnetic structures and also flare properties using three flare indexes. The results show the following. (I) Relative coverage and contrast of the magnetic features along with rate, power, and magnitude of flares increase on the SGB due to the deepening of the convective zone and more vigorous magnetic field production. (II) Magnetic activity of the F- and G-type stars on the SGB does not show dependency on the rotation rate and does not obey the saturation regime. This is the opposite of what we saw for the MS, in which the G-, K-, and M-type stars show clear dependency on the Rossby number. (III) The positive relationship between the magnetic features' stability and their relative coverage and contrast remains true on the SGB; though, it has a lower dependency coefficient in comparison with the MS. (IV) Magnetic proxies and flare indexes of the SGB stars increase with increasing relative mass of the convective zone.2021ApJ...906...40Ghttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/906/40CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toV/133 : Kepler Input Catalog (Kepler Mission Team, 2009)J/A+A/531/A8 : Activity indices and velocities for 890 stars (Jenkins+, 2011)J/AJ/141/50 : White-light flares on cool stars from Kepler (Walkowicz+, 2011)J/ApJ/743/48 : Stars with rotation periods & X-ray luminosity (Wright+, 2011)J/ApJS/209/5 : Superflares of Kepler stars. I. (Shibayama+, 2013)J/ApJ/776/67 : Rotational tracks (van Saders+, 2013)J/ApJ/788/L9 : Stellar parameters of KIC planet-host stars (Bastien+, 2014)J/A+A/572/A34 : Pulsating solar-like stars in Kepler (Garcia+, 2014)J/ApJS/211/2 : Revised stellar properties Q1-16 Kepler targets (Huber+, 2014)J/ApJS/211/24 : Rotation periods of Kepler MS stars (McQuillan+, 2014)J/ApJ/829/23 : Stellar flares from Q0-Q17 Kepler LCs (Davenport, 2016)J/ApJ/834/207 : Periodicity & magnitude Kepler LCs variation (Mehrabi+, 2017)J/ApJS/232/26 : Catalog of Kepler flare stars (Van Doorsselaere+, 2017)J/ApJ/866/99 : Radii of KIC stars & planets using Gaia DR2 (Berger+, 2018)J/ApJS/244/37 : Kepler flare star parameters from DR25 (Goodarzi+, 2019)J/ApJS/241/2 : Ionization profiles of 8 Galactic H II regions (Luisi+, 2019)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/906/40https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/906/40http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/906/40https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/906/40https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/906/40http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/906/40GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/906/40/table1 (Parameters of Kepler subgiant flare stars)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/906/40/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/906/40/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/906/40/table1?GETtext/xml+votable180.050000true286.096936137.45501060.0055555555555555565/3646 3689 3691-3692 3694 3734-3735 3740-3741 3778 3780 3782 3784 3792 6/14575 14577 14579-14580 14582 14588 14590-14591 14731 14733-14735 14744 14746 14750-14751 14761-14763 14772-14774 14794 14816 14827 14914-14916 14918-14919 14921-14925 14927-14929 14931-14934 14949 14955 14957-14959 14968-14969 14971-14973 15041 15044 15057 15059-15060 15104 15107 15109-15111 15116 15118-15119 15126 15132-15133 15141 15144 15146 15153 15155-15156 15158 15172-15174 15176 15200 15232https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/906/40?format=asciiOpticaldefaultJ/ApJ/906/40/table1Parameters of Kepler subgiant flare starsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintKICKepler catalog identifiermeta.id;meta.mainintPer[0.21/36.4] Stellar rotation perioddtime.periodfloatIAC[0.11/0.43] Auto-correlation indexstat.correlationdoubleReff[0.0001/0.1] Effective range light curve variationem.wl.effectivedoubleRf[0.0007/0.03] Time occupation ratio of flarestime;arith.ratiodoublePf[2.58e+20/2.04e+23] Total power of flaresphys.energydoubleMf[1.09e+23/2.7e+25] Average flux magnitude flaresphot.flux;stat.meandoubleThr[0.0001/0.009] Threshold value of flare detectionstat.fit.paramdoubleNf[38/672] Number of flaresmeta.numberintMass[0.8/1.27] Stellar masssolMassphys.massfloatRad[0.6/3.77] Stellar radiussolRadphys.size.radiusfloatSimbadSimbad column added by the CDSmeta.ref.urlcharTeff[5004/6709] Stellar effective temperatureKphys.temperature.effectivefloatlogg[3.58/4.68] log stellar surface gravitylog(cm.s**-2)phys.gravityfloatFe/H[-1.54/0.56] Metallicityphys.abund.ZfloatRo[0.02/2.01] Rossby numberstat.paramdoubleBerger+Display data from Berger+, 2018, J/ApJ/866/99meta.ref.urlchar_RAPosition from SIMBAD (right ascension part)degpos.eq.ra;meta.main_DEPosition from SIMBAD (declination part)degpos.eq.dec;meta.main