J/A+A/541/A9ivo://CDS.VizieR/J/A+A/541/A9doi:10.26093/cds/vizier.35410009CDSGomes da SilvaJ.SantosN. C.BonfilsX.DelfosseX.ForveilleT.,UdryS.DumusqueX.LovisC.2017-12-06T07:37:58Z2012-04-19T08:24:18ZCDS support team

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

cds-question@unistra.frm-starsradial-velocityDue to their low mass and luminosity, M dwarfs are ideal targets if one hopes to find low-mass planets similar to Earth by using the radial velocity (RV) method. However, stellar magnetic cycles could add noise or even mimic the RV signal of a long-period companion. Following our previous work that studied the correlation between activity cycles and long-term RV variations for K dwarfs we now expand that research to the lower-end of the main sequence. Our objective is to detect any correlations between long-term activity variations and the observed RV of a sample of M dwarfs. We used a sample of 27 M-dwarfs with a median observational timespan of 5.9 years. The cross-correlation function (CCF) with its parameters RV, bisector inverse slope (BIS), full-width-at-half- maximum (FWHM) and contrast have been computed from the HARPS spectrum. The activity index have been derived using the Na I D doublet. These parameters were compared with the activity level of the stars to search for correlations. We detected RV variations up to ~5m/s that we can attribute to activity cycle effects. However, only 36% of the stars with long-term activity variability appear to have their RV affected by magnetic cycles, on the typical timescale of ~6 years. Therefore, we suggest a careful analysis of activity data when searching for extrasolar planets using long-timespan RV data.2012A&A...541A...9Ghttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/541/A9CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/541/A9https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/541/A9http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/541/A9https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/541/A9https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/541/A9http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/541/A9GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/541/A9/stars (List of studied stars)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/541/A9/stars?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/541/A9/stars?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/541/A9/stars?GETtext/xml+votable180.050000true1.351667-37.35750.0055555555555555566/16391 18496 18666 19466 22309 22807 24227 24713 26583 27201 27392 28548 31781 33966 36078 39807 41591 42101 42255 42290 42459 42652 43187 44921 45322 46566 46632https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/541/A9?format=asciiOpticaldefaultJ/A+A/541/A9/starsList of studied starsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameSimbad namemeta.id;meta.maincharprimaryRAJ2000Simbad Hour of Right Ascension (J2000.0)pos.eq.ra;meta.mainDEJ2000Simbad Degree of Declination (J2000.0)pos.eq.dec;meta.mainBmagSimbad B band magnitudemagphot.mag;em.opt.BfloatVmagSimbad V band magnitudemagphot.mag;em.opt.VfloatSpTypeSimbad MK spectral typesrc.spTypecharSimbadSimbad column added by the CDSmeta.refcharJ/A+A/541/A9/table1Averages of RV, FWHM, contrast, BIS and NaI activity indexrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameTarget identificationmeta.id;meta.mainchar<BJD>Average Barycentric Modified Julian Datedtime.epochdoubleNNumber of measurements in the binmeta.numberint<RV>Average radial velocitykm/sspect.dopplerVeloc;stat.meandoublee_<RV>rms uncertainty on <RV>km/sstat.errorfloat<FWHM>Average Full-Width-at-Half-Maximum (FWHM) (1)km/sspect.line.widthdoublee_<FWHM>rms uncertainty on <FWHM>km/sstat.error;phys.angSizefloat<cont>Average contrast (1)km/sstat.fit.paramdoublee_<cont>rms uncertainty on <cont>km/sstat.errorfloat<BIS>Average Bissector Inverse Slope (BIS) (1)km/sstat.fit.paramdoublee_<BIS>rms uncertainty on <BIS>km/sstat.errorfloat<NaI>Average NaI activity indexphot.flux;arith.ratiofloate_<NaI>rms uncertainty on <NaI>stat.errorfloat