J/A+A/632/A37ivo://CDS.VizieR/J/A+A/632/A37doi:10.26093/cds/vizier.36320037CDSBrems S.S.Kuerster M.Trifonov T.Reffert S.Quirrenbach A.2020-04-06T14:45:43Z2019-11-25T10:05:29ZCDS support team

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

cds-question@unistra.frradial-velocityStars show various amounts of Radial Velocity (RV) jitter due to varying stellar activity levels. The typical amount of RV jitter as a function of stellar age and observational timescale has not been systematically quantified so far, although it is often larger than the instrumental precision of modern high-resolution spectrographs used for Doppler planet detection and characterization. We aim to empirically determine the intrinsic stellar RV variation for mostly G and K dwarf stars on different timescales and for different stellar ages independently of stellar models. We also focus on young stars (~<30Myr), where the RV variation is known to be large. We use archival FEROS and HARPS RV data of stars which were observed at least 30 times spread over at least two years. We then apply the Pooled Variance (PV) technique to these data sets to identify the periods and amplitudes of underlying, quasiperiodic signals. We show that the PV is a powerful tool to identify quasiperiodic signals in highly irregularly sampled data sets. We derive activity-lag functions for 20 assumingly single stars stars, where lag is the timescale on which the stellar jitter is measured. Since the ages of all stars are known, we also use this to formulate an activity-age-lag relation which can be used to predict the expected RV jitter of a star given its age and the timescale to be probed. The maximum RV jitter on timescales of decades decreases from over 500m/s for 5Myr old stars to 2.3m/s for stars with ages around 5Gyr. The decrease in RV jitter when considering a time scale of only 1d instead of 1yr is smaller by roughly a factor of 4 for stars with an age of about 5Myr, and a factor of 1.5 for stars with an age of 5Gyr. How fast the RV jitter increases with lag strongly depends on stellar age and reaches 99% of the maximum RV jitter between a few days for a few Myr old stars up to presumably decades or longer for stars with an age of a few Gyr.2019A&A...632A..37Bhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/632/A37CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/632/A37https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/632/A37http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/632/A37https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/632/A37https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/632/A37http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/632/A37GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/632/A37/stars (List of studied stars)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/632/A37/stars?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/632/A37/stars?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/632/A37/stars?GETtext/xml+votable180.050000true246.917875-24.36780560.0055555555555555566/20593 21177 22541 23140 26924 32937 33209 34586 34817 35853 36899 37408 37652 38593 39489 39523 41380 42022 42713 42751 42981 43066 46239 46734 47414 47742 48334https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/632/A37?format=asciidefaultJ/A+A/632/A37/starsList of studied starsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintTargetStellar IDmeta.id;meta.maincharRAJ2000Simbad right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Simbad declination (J2000)pos.eq.dec;meta.mainNobsNumber of radial velocity measurements in table E1 (tablee1.dat)meta.numberintVCShow the Radial Velocity curvesmeta.ref.urlcharSimbadSimbad column added by the CDSmeta.ref.urlcharJ/A+A/632/A37/tablee1Radial velocity data for all 27 starsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintTargetStellar IDmeta.id;meta.maincharInst[HAPRS, FEROS] Instrumentmeta.id;instrcharBJDBarycentric Julian Datedtime.epochdoubleRVRadial Velocitym/sphys.veloc;pos.heliocentricdoublee_RVError (std) of the Radial Velocitym/sstat.errorfloat