J/ApJ/871/193ivo://CDS.VizieR/J/ApJ/871/193doi:10.26093/cds/vizier.18710193CDSHe L.Wang S.Liu J.Soria R.Bai Z.Yang H.Bai YuGuo J.2021-07-15T07:24:02Z2020-04-22T13:01:09ZCDS support team

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

cds-question@unistra.frx-ray-sourcesstellar-agesstellar-massesstellar-spectral-typesmetallicitystellar-distancevisible-astronomybroad-band-photometryline-intensitiesWe probed stellar X-ray activity over a wide range of stellar parameters, using Chandra and Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) data. We measured the X-ray-to-bolometric luminosity ratio (R_X_=L_X_/L_bol_) for 484 main-sequence stars and found a bimodal distribution for G and K types. We interpret this bimodality as evidence of two subpopulations with different coronal temperatures, which are caused by different coronal heating rates. Using the metallicity and velocity information, we find that both of the subpopulations are mostly located in the thin disk. We find no trend of R_X_ with stellar age for stars older than ~4Gyr; there is a trough in the R_X_ versus age distribution, with the lowest range of R_X_ appearing at ages around 2Gyr. We then examined the correlation between R_X_ and R_H{alpha}_ (proxy of chromospheric activity): we find that the two quantities are well correlated, as found in many earlier studies. Finally, we selected a sample of 12 stars with X-ray flares and studied the light-curve morphology of the flares. The variety of flare profiles and timescales observed in our sample suggests the contribution of different processes of energy release.2019ApJ...871..193Hhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/871/193CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toB/chandra : The Chandra Archive Log (CXC, 1999-2014)VIII/85 : SPECFIND V2.0 Catalog of radio continuum spectra (Vollmer+, 2009)I/322 : UCAC4 Catalogue (Zacharias+, 2012)II/349 : The Pan-STARRS release 1 (PS1) Survey - DR1 (Chambers+, 2016)V/153 : LAMOST DR4 catalogs (Luo+, 2018)IX/57 : The Chandra Source Catalog (CSC), Release 2.0 (Evans+, 2019)J/AJ/111/439 : Chromospheric emission in late-type stars. (Henry+ 1996)J/A+A/311/211 : X-ray flare of CF Tuc (=HD 5303) (Kuerster+ 1996)J/A+A/348/897 : Ages of main-sequence stars (Lachaume+, 1999)J/AJ/126/2048 : NStars project: the Northern Sample. I. (Gray+, 2003)J/A+A/397/147 : Activity-rotation relationship in stars (Pizzolato+ 2003)J/AJ/130/873 : Properties of BQS objects in SDSS DR3 area (Jester+, 2005)J/MNRAS/367/781 : XMM observations of NGC 2547 (Jeffries+, 2006)J/MNRAS/372/163 : Activity indices for southern stars (Jenkins+, 2006)J/A+A/469/309 : Chromospheric activity late-type stars (Cincunegui+, 2007)J/A+A/475/677 : X-ray emission from A-type stars (Schroeder+, 2007)J/A+A/485/571 : Metallicities & activities southern stars (Jenkins+, 2008)J/ApJ/687/1264 : Age estimation for solar-type dwarfs (Mamajek+, 2008)J/ApJS/181/444 : X-emitting stars identified from RASS/SDSS (Agueros+,2009)J/ApJ/725/480 : Stellar X-ray sources in the COSMOS survey (Wright+, 2010)J/A+A/531/A8 : Activity indices & velocities, 890 stars (Jenkins+, 2011)J/ApJ/743/48 : Stars with rotation periods & X-ray lum. (Wright+, 2011)J/other/RAA/11.924 : Atmospheric parameters for 771 stars (Wu+, 2011)J/A+A/551/L8 : Chromospheric activity of field stars (Pace, 2013)J/MNRAS/431/2063 : UV/X-ray activity of M dwarfs within 10pc (Stelzer+, 2013)J/A+A/581/A28 : Stellar X-ray flares from the 2XMM catalog (Pye+, 2015)J/A+A/596/A76 : H{alpha}-activity in the SARG binary survey (Sissa+, 2016)J/ApJS/224/40 : Catalog of Chandra ACIS point like sources (Wang+, 2016)J/ApJ/829/20 : Chandra ACIS survey in nearby galaxies. II (Wang+, 2016)J/ApJ/849/36 : Flaring activity of M dwarfs in Kepler field (Yang+, 2017)J/ApJ/835/61 : Chromospherically active stars in RAVE. II. (Zerjal+,2017)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/871/193https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/871/193http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/871/193https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/871/193https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/871/193http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/871/193GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/871/193/stars (LAMOST (Table 2) and key results (Table 3) for the stars in our sample)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/871/193/stars?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/871/193/stars?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/871/193/stars?GETtext/xml+votable180.050000true3.0337550.5041670.0055555555555555565/2538 6814 6/24 301 463 528 609 757 932 1128 1154 1198 1199 1287 1390 1466 1467 1468 1539 1650 1694 1784 1791 1848 1852 2051 2117 2227 2232 2245 2374 2397 2409 2432 2436 2564 2572 2623 2704 2705 2708 2709 2808 2866 2921 3093 4108 4121 4124 4150 4181 4206 4215 4341 4342 4344 4350 4406 4511 4609 4649 4672 4689 4690 4698 4719 4758 4759 4765 4775 4804 4850 4952 4966 4976 5018 5046 5048 5049 5051 5067 5142 5241 5264 5585 5625 5660 5664 5701 5743 5881 5890 5894 5930 5931 5975 6001 6011 6045 6069 6071 6073 6075 6077 6083 6084 6086 6181 6382 6383 6448 6609 6618 6639 6645 6760 6826 6926 7178 7227 7242 7273 7316 7320 7424 8220 8264 8288 8338 8339 8555 8659 8914 8969 9072 9145 9146 9147 9148 9150 9151 9175 9375 9446 9466 9496 9640 9747 9831 9997 10037 10051 10364 10371 10388 10471 10484 10512 10513 10516 10517 10518 10775 11001 11027 11149 11180 11194 11206 11347 11364 11424 11425 11427 11428 11433 11434 12553 12577 13401 13574 13632 13707 13760 14227 14272 14621 14645 14670 14671 14691 14692 14693 14696 14704 14754 14777 14779 14858 14925 14933 15133 15154 17745 17755 17767 17772 17822 18011 18086 18184 18398 18795 18894 18935 19061 19130 19157 19204 19451 19935 20021 20083 20292 21439 21447 21456 21458 21766 21872 21916 21946 21982 22159 22208 22241 22243 22249 22252 22254 22255 22316 22318 22364 22505 22507 22805 22830 22855 22895 22972 23167 23185 23223 23306 23474 23551 23637 23674 23766 23830 23952 23969 23995 24003 24032 24185 24188 24227 24325 24339 24345 24449 24460 24522 25439 25934 25990 26055 26180 26189 26209 26212 26213 26292 26313 26995 27009 27075 27096 27126 27156 27174 27224 27245 27314 27318 27342 27652 27661 27687 27734 27735 27739 27756 27765 27771 27773 27848 27937 27944 28032 28045 28149 28172 28471 28486 28574 28632 31453 31461 31509 31537 31552 31621 31625 31725 31730https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/871/193?format=asciiX-rayOpticaldefaultJ/ApJ/871/193/starsLAMOST (Table 2) and key results (Table 3) for the stars in our samplerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNxNumber of X-ray measurements for this star (link to Table 1)meta.numberintnullableCXOGSGObject identifier from Wang+ 2016, J/ApJS/224/40meta.id;meta.maincharprimaryHaDisplay the H{alpha} data for this star (link to Table 4)meta.ref.urlcharXfl1: this star has X-ray flare data (link to Table 5)meta.ref.urlintnullableSpTSpectral type subclass (1)src.spTypecharTeff[3586/8925] Stellar effective temperature (2)Kphys.temperature.effectiveinte_Teff[58/493] Uncertainty in TeffKstat.error;phys.temperature.effectiveintlogg[1.8/5.6] log of surface gravity (2)log(cm.s**-2)phys.gravityfloate_logg[0.06/0.33] Uncertainty in logglog(cm.s**-2)stat.errorfloatE(B-V)[0/1] Extinction (2)magphot.color.excessfloat[Fe/H][-1.8/0.71]? Metallicity (2)phys.abund.Zfloatnullablee_[Fe/H][0.06/0.41]? Uncertainty in [Fe/H]stat.error;phys.abund.Fefloatnullable[alpha/Fe][-0.39/0.5]? alpha element abundance relative to Fe (2)phys.abundfloatnullablee_[alpha/Fe][0.03/0.15]? Uncertainty in [alpha/Fe]stat.error;phys.abundfloatnullableDist[21/5604] Distance (2)pcpos.distanceinte_Dist[2/1399] Uncertainty in Distpcstat.errorintAge[0.36/16]? Stellar Age (3)Gyrtime.agefloatnullablee_Age[0.12/4.3]? Uncertainty in AgeGyrstat.error;time.agefloatnullableMass[0.85/2.71]? Stellar Mass (3)solMassphys.massfloatnullablee_Mass[0.04/0.41]? Uncertainty in MasssolMassstat.error;phys.massfloatnullableVmag[8.6/17.3] Extinction-corrected V-band magnitudemagphot.mag;em.opt.Vfloate_Vmag[0.09/1] Uncertainity on Vmagmagstat.error;phot.magfloatr_VmagSource of V-band magnitude (5)meta.ref;pos.framecharMbol[-3.1/11] Bolometric magnitudemagphot.mag.bolfloatuFlux[0.02/10072] Unabsorbed 0.3-8keV X-ray flux in 10^-15^erg/cm2/s units1e-15mW.m**-2phot.flux;em.X-raydoublee_uFlux[0.02/1964] Uncertainty in uFlux1e-15mW.m**-2stat.errorfloatLumX[4.5e+25/7.5e+32] 0.3-8keV X-ray luminosity in erg/s units1e-07Wphys.luminosity;em.X-rayfloate_LumX[4.9e+25/4.7e+32] Uncertainty in LumX1e-07Wstat.errorfloatlogRx[-6.6/-1.9] log, X-ray-to-bolometric luminosity ratiophys.luminosity;arith.ratiofloate_logRx[0.09/1.2] Uncertainty in logRxstat.errorfloatHR[-1.2/1.4] Hardness ratio (4)phot.flux;arith.ratiofloate_HR[0.01/2.3] Uncertainty in HRstat.errorfloatLCInteractive Plot (if more than 4 X-ray measurements)meta.ref.urlcharLAMOSTDisplay the LAMOST -DR1 (V/146) and -DR4 data (V/153) within 3"meta.ref.urlcharUCAC4Display the UCAC4 data (Zacharias+ 2012, I/153) within 3"meta.ref.urlcharPS1Display the PS1 data (Chambers+ 2016, II/349) within 1.5"meta.ref.urlcharSimbadSimbad column added by the CDSmeta.ref.urlchar_RAPositions from CXOGSG names (right ascension part)degpos.eq.ra;meta.main_DEPositions from CXOGSG names (declination part)degpos.eq.dec;meta.mainJ/ApJ/871/193/table1X-ray information for the 484 stars in our sampleDetChandra ACIS detectormeta.notecharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintCXOGSGObject identifier from Wang+ 2016, J/ApJS/224/40meta.id;meta.maincharObsID[13/16543] Chandra observation identifiermeta.id;obs.param;obsintExp[128/189850] Chandra exposure time after deadtime correctionstime.duration;obs.exposuredoubleMJD[51439/56755] Modified Julian Date at the beginning of observation (JD-2400000.5)dtime.epochintVigF[0.008/1.1] Vignetting factorinstr.paramfloatl_CRLimit flag on CR (1)meta.code.errorcharCR[0.02/177]? Net count rate, 0.5-7keV1000count.s**-1phot.count;em.X-rayfloatnullablee_CR[0.02/9.7]? Lower uncertainty in CR1000count.s**-1stat.errorfloatnullableu_e_CRUncertainty flag on e_CR (2)meta.code.errorcharE_CR[0.04/9.7]? Upper uncertainty in CR1000count.s**-1stat.error;stat.maxfloatnullablel_FluxLimit flag on Flux (1)meta.code.error;phot.fluxcharFlux[0.01/848]? Absorbed X-ray flux, 0.5-7keV in 10^-15^erg/cm^2^/s units1e-15mW.m**-2phot.flux;em.X-rayfloatnullablee_Flux[0.01/47]? Lower uncertainty in Flux1e-15mW.m**-2stat.error;phot.fluxfloatnullableu_e_FluxUncertainty flag on e_Flux (2)meta.code.errorcharE_Flux[0.02/47]? Upper uncertainty in Flux1e-15mW.m**-2stat.error;stat.maxfloatnullableJ/ApJ/871/193/table4Stars with H{alpha} emission lines in our samplerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintCXOGSGObject identifiermeta.id;meta.maincharEW[0.35/9] Equivalent Width, H{alpha}0.1nmspect.line.eqWidthfloate_EW[0.02/0.33] Uncertainty in EW0.1nmstat.error;spect.line.eqWidthfloatEWp[1.9/9.7] Excess H{alpha} equivalent width over chromospheric emission0.1nmspect.line.eqWidthfloatlogRHa[-4/-3.2] log, H{alpha} emission index, LH{alpha}/Lbolspect.indexfloate_logRHa[0.03/0.11] Uncertainty in logRHastat.errorfloatJ/ApJ/871/193/table5Stars with X-ray flares in our samplerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintCXOGSGObject identifier from Wang+ 2016, J/ApJS/224/40meta.id;meta.maincharSpTSpectral type subclasssrc.spTypecharObsID[1663/13656] Chandra Observation identifiermeta.id;obs.param;obsintl_dT[>]? Limit flag on dTmeta.code.errorchardT[4000/43000] Flare durationstime.durationint