J/AJ/165/188ivo://CDS.VizieR/J/AJ/165/188doi:10.26093/cds/vizier.51650188CDSGuzik J.A.Baran A.S.Sanjayan S.Nemeth P.Hedlund A.M.,Jackiewicz J.Dauelsberg L.R.2025-05-06T20:09:04Z2023-09-29T07:23:12ZCDS support team

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

cds-question@unistra.fropen-star-clustersvariable-starsvisible-astronomyspectroscopyNGC6819 is an open cluster of age 2.4Gyr that was in the NASA Kepler spacecraft's field of view from 2009 to 2013. The central part of the cluster was observed in a 200x200pixel "superstamp" during these four years in 30minute cadence photometry, providing a unique, high-precision, long time-series data set. The cluster contains "blue straggler" stars, i.e., stars on the main sequence above the cluster turnoff that should have left the main sequence to become red giants. We present light curves and pulsation frequency analyses derived from custom photometric reductions for five confirmed cluster members-four blue stragglers and one star near the main-sequence turnoff. Two of these stars show a rich spectrum of {delta}Scuti pulsation modes, with 236 and 124 significant frequencies identified, respectively, while two stars show mainly low-frequency modes, characteristic of {gamma}Doradus variable stars. The fifth star, a known active X-ray binary, shows only several harmonics of two main frequencies. For the two {delta}Scuti stars, we use a frequency separation-mean density relation to estimate their mean densities, and then use these values along with their effective temperature to derive their stellar masses and radii. For the two stars showing low frequencies, we searched for period-spacing sequences that may be representative of gravity-mode or Rossby-mode sequences, but found no clear sequences. The common age for the cluster members, considered along with the frequencies, will provide valuable constraints for asteroseismic analyses, and may shed light on the origin of the blue stragglers.2023AJ....165..188Ghttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/165/188CatalogResearchIsServedByTAP 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/ApJ/729/L10 : KIC stars properties in NGC 6791 and NGC 6819 (Basu+, 2011)J/A+A/534/A125 : Variability of A- & F-stars from Kepler (Uytterhoeven+ 2011)J/MNRAS/427/2180 : GALEX survey subdwarf atmospheric parameters (Nemeth+, 2012)J/AJ/148/38 : WIYN open cluster LX. RV survey of NGC6819 (Milliman+, 2014)J/A+A/583/A65 : Active Kepler stars differential rotation (Reinhold+, 2015)J/A+A/574/A17 : Period spacings in gamma Dor stars (Van Reeth+, 2015)J/AJ/151/66 : Velocities WOCS24009 & WOCS40007 in NGC6819 (Brewer+, 2016)J/ApJS/224/41 : Frequency spacing of {delta}Scuti stars. II. (Paparo+, 2016)J/A+A/614/A46 : delta Scuti stars Teff-{nu}max (Barcelo Forteza+, 2018)J/MNRAS/490/4040 : {delta}Scuti & {gamma}Doradus stars in TESS (Antoci+, 2019)J/AJ/158/163 : Li abundance values for stars in NGC6819 (Deliyannis+, 2019)J/MNRAS/491/3586 : 611 {gamma} Doradus stars Kepler data (Li+, 2020)J/A+A/650/A67 : Blue & yellow straggler stars in open clusters (Rain+, 2021)J/ApJS/258/39 : Kepler IRIS cat LCs NGC6791 & NGC6819 fields (Colman+, 2022)J/AcA/72/77 : Variable star population in NGC 6791 (Sanjayan+, 2022)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/165/188https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/165/188http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/165/188https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/165/188https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/165/188http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/165/188GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/AJ/165/188/table2 (Summary of the properties of the five NGC6819 stars observed in the Kepler Superstamp field)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/165/188/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/165/188/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/165/188/table2?GETtext/xml+votable180.050000true295.322766840.184311170.0055555555555555566/14752-14753https://cdsarc.cds.unistra.fr/viz-bin/moc/J/AJ/165/188?format=asciiOpticaldefaultJ/AJ/165/188/table2Summary of the properties of the five NGC6819 stars observed in the Kepler Superstamp fieldSimbadSimbad column added by the CDSmeta.ref.urlcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintKICKIC identifiermeta.id;meta.maincharprimaryf_KICFlag on KIC (1)meta.codecharRefReference(s) used (2)meta.refcharRAJ2000[295/296] Degree of right ascension (J2000)degpos.eq.ra;meta.mainDEJ2000[40/41] Degree of declination (J2000)degpos.eq.dec;meta.mainTICTIC identifiermeta.idVmag[12.9/15.8] V-band magnitudemagphot.mag;em.opt.Vfloate_Vmag[0.04/0.2] Error on Vmagmagstat.error;phot.magfloatTeff[5493/7328] Effective temperatureKphys.temperature.effectiveinte_Teff[122/130] Error on TeffKstat.error;phys.temperature.effectiveintlogg[3.44/4.25] Surface gravitycm.s**-2phys.gravityfloate_logg[0.096]? Error on loggcm.s**-2stat.errorfloatnullableRad[1.49/3.93] Stellar radiussolRadphys.size.radiusfloate_Rad[0.26]? Error on RadsolRadstat.errorfloatnullableMass[0.96/1.66] Stellar masssolMassphys.massfloate_Mass[0.25]? Error on MasssolMassstat.error;phys.massfloatnullableLum[3.6/34.6] Stellar luminositysolLumphys.luminosityfloate_Lum[4.03]? Error on LumsolLumstat.errorfloatnullableSpTH-R diagram locationsrc.spTypecharNfreq[17/236] Number of frequencymeta.numberintClassClassificationsrc.classcharJ/AJ/165/188/tablea1Significant frequencies for KIC 5024468, 5024084, 5024455, 5113357, 5112843KICKepler Input Catalog number (1)meta.id;meta.mainintrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintFNFrequency Number (2)meta.idcharFreq1[0.07/36.5] Frequency, c/dem.freq;src.vardoublee_Freq1[1e-07/0.0004]? Uncertainty in Freq1, c/dstat.errordoublenullableFreq2[0.87/423] FrequencyuHzem.freq;src.vardoublee_Freq2[1.2e-06/0.005]? Uncertainty in Freq2uHzstat.errordoublenullablePer[0.02/13.2] Perioddtime.perioddoublee_Per[1e-09/0.002]? Uncertainty in Perdstat.errordoublenullableAmp[0.018/21.4] Amplitude, parts per thousandsrc.var.amplitudefloate_Amp[0.003/0.03] Uncertainty in Amp parts per thousandstat.errorfloatSNR[4.18/3881] Signal-to-Noise Ratiostat.snrfloat