J/A+A/511/A54ivo://CDS.VizieR/J/A+A/511/A54doi:10.26093/cds/vizier.35110054CDSSantos N.C.Gomes da Silva J.Lovis C.Melo C.2017-07-10T06:21:44Z2010-04-19T14:20:19ZCDS support team

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

cds-question@unistra.frg-starsradial-velocityThe ever increasing level of precision achieved by present and future radial velocity instruments is opening the way to the discovery of very low mass, long period planets (e.g. solar-system analogs). These systems will be detectable as low amplitude signals in radial-velocity (RV). However, an important obstacle to their detection may be the existence of stellar magnetic cycles with similar timescales. Here we present the results of a long term program to measure simultaneously radial-velocities and stellar activity indicators (CaII, H{alpha}, HeI) for a sample of stars with known activity cycles. Our results suggest that all these stellar activity indexes can be used to trace the stellar magnetic cycle in solar-type stars. Further to this, we find clear indications that different parameters of the HARPS cross-correlation function (BIS, FWHM, and Contrast) are also sensitive to activity level variations. Finally, we show that though in a few cases slight correlations or anti-correlations between radial-velocity and the activity level of the star exist, their origin is still not clear. We can however conclude that for our targets (early-K dwarfs) we do not find evidence for radial-velocity variations induced by variations of the stellar magnetic cycle with amplitudes significantly above 1m/s.2010A&A...511A..54Shttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/511/A54CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/511/A54https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/511/A54http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/511/A54https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/511/A54https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/511/A54http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/511/A54GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/511/A54/table1 (List of target stars)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/511/A54/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/511/A54/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/511/A54/table1?GETtext/xml+votable180.050000true12.09573835.2806150.0055555555555555566/137 17137 18139 19312 22708 22818 31101 31130https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/511/A54?format=asciiOpticaldefaultJ/A+A/511/A54/table1List of target starsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHDStar HD numbermeta.id;meta.mainintprimarym_HDMultiplicity index on HDmeta.code.multipcharVmagV magnitudemagphot.mag;em.opt.VfloatB-VB-V colour indexmagphot.color;em.opt.B;em.opt.VfloatSpTypeMK spectral typesrc.spTypecharProtRotational period (1)dtime.periodintObsFFirst observation datetime.epoch;obsnullableObsLLast observation datetime.epochnullableNNumber of nights each star was observedmeta.numberint<S/N>Average signal-to-noise ratio of individual spectra in HARPS order 6 (near {lambda}=4000{AA})stat.snrintActPlot of the CaII, Halpha and HeI activity levelsmeta.ref.urlcharSimbadSimbad column added by the CDSchar_RARight Ascension (J2000) from SIMBAD (not part of the original data)degpos.eq.ra;meta.main_DEDeclination (J2000) from SIMBAD (not part of the original data)degpos.eq.dec;meta.mainJ/A+A/511/A54/table5CaII S activity level as a function of timerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHDStar HD numbermeta.id;meta.mainintBJDBarycentric Julian datedtime.epochdoubleSMWCaII activity level in MW scale (S_MW_ scale, see Baliunas et al. 1995ApJ...438..269B)phot.flux;arith.ratiofloate_SMWStatistical error in SMWstat.errorfloatJ/A+A/511/A54/HaHeH{alpha} and HeI activity levels as a function of timerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHDStar HD numbermeta.id;meta.mainintBJDBarycentric Julian datedtime.epochdoubleHalphaH{alpha} activity levelmeta.notedoublee_HalphaStatistical error in H{alpha}stat.errordoubleHeIHeI activity levelphot.flux;arith.ratiodoublee_HeIStatistical error in HeIstat.errordoubleJ/A+A/511/A54/table8Yearly averages of CaII-S, RV, BIS, FWHM, and ContrastrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHDStar HD numbermeta.id;meta.mainintYearYear of the measurementsyrtime.epochint<SMW>? Average activity level in MW scalephot.flux;arith.ratiodoublenullablee_<SMW>? rms uncertainty on <SMW>stat.errordoublenullable<RV>Average radial velocitykm/sspect.dopplerVeloc;stat.meandoublee_<RV>rms uncertainty on <RV>km/sstat.errorfloat<BIS>Average Bisector Inverse Slope (BIS) value (1)km/sstat.fit.paramdoublee_<BIS>rms uncertainty on <BIS>km/sstat.errordouble<Cont>Average Cross-Correlation Function's Contrast value (1)%stat.fit.paramdoublee_<Cont>rms uncertainty on <Contrast>%stat.errordouble<FWHM>Average FWHM value (1)km/sstat.fit.paramdoublee_<FWHM>rms uncertainty on <FWHM>km/sstat.error;phys.angSizedoubleBJD1? Average Barycentric Julian Date for SMW valuesdtime.epochdoublenullableBJD2Average Barycentric Julian Date for RV, FWHM, BIS, and Contrast valuesdtime.epochdouble