J/ApJS/200/15ivo://CDS.VizieR/J/ApJS/200/15doi:10.26093/cds/vizier.22000015CDSAnglada-Escude G.Butler R.P.2017-06-01T08:51:59Z2012-08-07T08:24:39ZCDS support team

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

cds-question@unistra.frradial-velocitym-starssolar-system-planetsspectroscopymultiple-starsDoppler spectroscopy has uncovered or confirmed all the known planets orbiting nearby stars. Two main techniques are used to obtain precision Doppler measurements at optical wavelengths. The first approach is the gas cell method, which consists of least-squares matching of the spectrum of iodine imprinted on the spectrum of the star. The second method relies on the construction of a stabilized spectrograph externally calibrated in wavelength. The most precise stabilized spectrometer in operation is the High Accuracy Radial velocity Planet Searcher (HARPS), operated by the European Southern Observatory in La Silla Observatory, Chile. The Doppler measurements obtained with HARPS are typically obtained using the cross-correlation function (CCF) technique. This technique consists of multiplying the stellar spectrum by a weighted binary mask and finding the minimum of the product as a function of the Doppler shift. It is known that CCF is suboptimal in exploiting the Doppler information in the stellar spectrum. Here we describe an algorithm to obtain precision radial velocity measurements using least-squares matching of each observed spectrum to a high signal-to-noise ratio template derived from the same observations. This algorithm is implemented in our software HARPS-TERRA (Template-Enhanced Radial velocity Re-analysis Application). New radial velocity measurements on a representative sample of stars observed by HARPS are used to illustrate the benefits of the proposed method. We show that, compared with CCF, template matching provides a significant improvement in accuracy, especially when applied to M dwarfs.2012ApJS..200...15Ahttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJS/200/15CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toI/311 : Hipparcos, the New Reduction (van Leeuwen, 2007)III/185 : Search for Jupiter-Mass Companions (Walker+, 1995)J/A+A/541/A9 : M dwarfs activity and radial velocity (Gomes da Silva+, 2012)J/A+A/534/A58 : HD20794, HD85512, HD192310 HARPS RVs (Pepe+, 2011)J/A+A/527/A140 : Mass limits on substellar companions (Reffert+, 2011)J/A+A/526/A141 : Velocity of Gl 676A and HIP 12961 (Forveille+, 2011)J/A+A/534/A133 : Proxima Cen chromospheric emission lines (Fuhrmeister+, 2011)J/other/Sci/330.653 : Detected planets in the Eta-Earth Survey (Howard+, 2010)J/A+A/505/859 : M dwarfs radial velocities (Zechmeister+, 2009)J/A+A/487/373 : Spectroscopic parameters of 451 HARPS-GTO stars (Sousa+, 2008)J/ApJ/646/505 : Catalog of nearby exoplanets (Butler+, 2006)J/ApJS/141/503 : Radial Velocities for 889 late-type stars (Nidever+, 2002)J/A+A/325/159 : Companions to M dwarfs within 5pc (Leinert+ 1997)http://archive.eso.org/wdb/wdb/eso/repro/form : FEROS/HARPS data query formhttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJS/200/15https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJS/200/15http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJS/200/15https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJS/200/15https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJS/200/15http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJS/200/15GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJS/200/15/stars (List of the stars studied (from table2 of paper))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJS/200/15/stars?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJS/200/15/stars?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJS/200/15/stars?GETtext/xml+votable180.050000true262.5466667-51.63697220.0055555555555555566/17425 31781 34181 36697 38461 40692 41591 42101 424597.952274030004205e-20 3.852589004194616e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJS/200/15?format=asciiOpticaldefaultJ/ApJS/200/15/starsList of the stars studied (from table2 of paper)KmagSimbad K band magnitudemagphot.mag;em.IR.KfloatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameSimbad namemeta.id;meta.maincharVCPlot of the velocity curvemeta.ref.urlcharRAJ2000Simbad Hour of Right Ascension (J2000.0)pos.eq.ra;meta.mainDEJ2000Simbad Degree of Declination (J2000.0)pos.eq.dec;meta.mainVmagSimbad V band magnitudemagphot.mag;em.opt.VfloatSpTypeSimbad MK spectral typesrc.spTypecharTab[5/10] Number of table with RV datameta.numberintPer? Orbital perioddtime.periodfloatnullableSimbadSimbad column added by the CDSmeta.refcharJ/ApJS/200/15/table5Differential RV and S-index measurements for {tau} Cet, HD 85512, GJ 676A, and {epsilon} ErirecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameStar identifier (1)meta.id;meta.maincharJDJulian Date of the observationdtime.epochdoubleRVDifferential TERRA radial velocitym/sphys.veloc;arith.diffdoublee_RVError in RVm/sstat.errordoubleRVCCFDifferential CCF radial velocitym/sphys.veloc;arith.diffdoublee_RVCCFError in RVCCFm/sstat.errordoubleSMWMt. Wilson S-index activity measurementspect.indexdoublee_SMWError in SMWstat.errordoubleJ/ApJS/200/15/table6RV measurements for Barnard's Star, Kapteyn's Star, and Proxima CenrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameStar identifier (1)meta.id;meta.maincharJDJulian Date of the observationdtime.epochdoubleRVDifferential TERRA radial velocitym/sphys.veloc;arith.diffdoublee_RVError in RVm/sstat.errordoubleRVCCFDifferential CCF radial velocitym/sphys.veloc;arith.diffdoublee_RVCCFError in RVCCFm/sstat.errordoubleRVRedDifferential TERRA red radial velocity (2)m/sphys.veloc;arith.diffdoublee_RVRedError in RVRedm/sstat.errordoubleJ/ApJS/200/15/table7Measurements on HD 69830recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintJDJulian Date of the observationdtime.epochdoubleRVDifferential TERRA radial velocitym/sphys.veloc;arith.diffdoublee_RVError in RVm/sstat.errordoubleRVRedDifferential TERRA red radial velocity (1)m/sphys.veloc;arith.diffdoublee_RVRedError in RVRedm/sstat.errordoubleSMWMt Wilson S-index activity measurementspect.indexdoublee_SMWError in SMWstat.errordoubleJ/ApJS/200/15/table10Differential RV measurements on GJ 667C used in Anglada-Escude et al. (2012ApJ...751L..16A)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintInstInstrument: HARPS, PFS or HIRESinstrcharJDJulian Date of the observationdtime.epochdoubleRVDifferential radial velocitym/sphys.veloc;arith.diffdoublee_RV? Error in RVm/sstat.errorfloatnullable