J/A+A/616/A155ivo://CDS.VizieR/J/A+A/616/A155doi:10.26093/cds/vizier.36160155CDSLanza A.F.Malavolta L.Benatti S.Desidera S.Bignamini A.,Bonomo A.S.Esposito M.Figueira P.Gratton R.Scandariato G.,Damasso M.Sozzetti A.Biazzo K.Claudi R.U.Cosentino R.Covino E.,Maggio A.Masiero S.Micela G.Pagano I.Piotto G.Poretti E.,Smareglia R.Affer L.Boccato C.Borsa F.Boschin W.Giacobbe P.,Knapic C.Leto G.Maldonado J.Mancini L.Martinez Fiorenzano A.,Messina S.Nascimbeni V.Pedani M.Rainer M.2018-09-28T08:33:13Z2018-09-07T07:53:03ZCDS support team

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

cds-question@unistra.frastronomical-modelsspectroscopyStellar activity is the ultimate source of radial-velocity (hereinafter RV) noise in the search for Earth-mass planets orbiting late-type main-sequence stars. We analyse the performance of four different indicators and the chromospheric index logR'_HK_ in detecting RV variations induced by stellar activity in 15 slowly rotating vsini<=5km/s), weakly active (logR'_HK_<=-4.95) solar-like stars observed with the high-resolution spectrograph High Accuracy Radial velocity Planet Searcher for the Northern hemisphere (HARPS-N). We consider indicators of the asymmetry of the cross-correlation function (CCF) between the stellar spectrum and the binary weighted line mask used to compute the RV, that is the bisector inverse span (BIS), {Delta}V, and a new indicator V_asy(mod)_ together with the full width at half maximum (FWHM) of the CCF. We present methods to evaluate the uncertainties of the CCF indicators and apply a kernel regression (KR) between the RV, the time, and each of the indicators to study their capability of reproducing the RV variations induced by stellar activity. The considered indicators together with the KR prove to be useful to detect activity-induced RV variations in ~47+/-18 percent of the stars over a two-year time span when a significance (two-sided p-value) threshold of one percent is adopted. In those cases, KR reduces the standard deviation of the RV time series by a factor of approximately two. The BIS, the FWHM, and the newly introduced V_asy(mod)_ are the best indicators, being useful in 27+/-13, 13+/-9, and 13+/-9 percent of the cases, respectively. The relatively limited performances of the activity indicators are related to the very low activity level and vsini of the considered stars. For the application of our approach to sun-like stars, a spectral resolution allowing {lambda}/{Delta}{lambda}>=10^5^ and highly stabilized spectrographs are recommended.2018A&A...616A.155Lhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/616/A155CatalogResearchIsServedByTAP VizieR generic servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/616/A155https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/616/A155http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/616/A155https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/616/A155https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/616/A155http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/616/A155GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapdefaultJ/A+A/616/A155/outputExample output filee_contsError on conts (e_cont_s)stat.errordoublee_FWHMsError of fwhms (e_fwhm_s)km/sstat.errordoublerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintTimeSolar system barycentric JD (time) (1)dtime.epochdoubleRVRadial velocity (rv)km/sphys.veloc;pos.heliocentricdoublee_RVError on radial velocity (e_rv)km/sstat.errordoublemaxcppMaximum number of counts per pixel (maxcpp)phot.count;stat.maxlongBISLine bisector slope (bis)km/sarith.grad;spect.linedoublee_BISError on line bisector slope (e_bis)km/sstat.errordoubledeltavdeltav indicator (delta_v)km/sphys.veloc;arith.diffdoublee_deltavError on deltav indicator (e_delta_v)km/sstat.errordoublevasyVasy indicator of Figuera et al. (2013A&A...557A..93F) (vasy)stat.fit.paramdoublee_vasyError on the vasy of Figueira et al. (2013A&A...557A..93F) (e_vasy)stat.errordoublevasymodModified vasy indicator (present work) (vasymod)stat.fit.paramdoublee_vasymodError of vasymod (e_vasymod)stat.errordoubleFWHMdrsFWHM as given by the DRS (fwhmdrs)km/sspect.line.widthdoubleFWHMfitFWHM as given by a Gaussian fit to CCF (fwhmfit)km/sspect.line.widthdoublee_FWHMError on FWHM computed by mpfit.pro (e_fwhm)km/sstat.error;phys.angSizedoublecont-drsCCF contrast given by the DRS (cont_drs)stat.fit.paramdoublecontrastCCF contrast computed by mpfit.pro (contrast)stat.fit.paramdoublee_contrError on the CCF contrast by mpfit.pro (e_contr)stat.errordoubleFWHMsMedian FWHM of 200 CCF realizations (fwhm_s)km/sspect.line.widthdoubledeltavsMedian delta_v of 200 CCF realizations (delta_vs)km/sphys.veloc;arith.diffdoublee_deltavsError on deltavs (e_delta_vs)km/sstat.errordoublecontsMedian contrast of 200 CCF realizations (cont_s)stat.fit.paramdouble