J/AJ/162/14ivo://CDS.VizieR/J/AJ/162/14doi:10.26093/cds/vizier.51620014CDSAkeson R.Beichman C.Kervella P.Fomalont E.Benedict G.F.2022-03-14T06:46:54Z2021-11-22T06:39:31ZCDS support team

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

cds-question@unistra.frmultiple-starsg-starsastrometrymillimeter-astronomyphotometrysubmillimeter-astronomyvisible-astronomyradial-velocityAlpha Centauri A is the closest solar-type star to the Sun and offers the best opportunity to find and ultimately to characterize an Earth-sized planet located in its habitable zone. Here, we describe initial results from an Atacama Large Millimeter/submillimeter Array (ALMA) program to search for planets in the {alpha} Cen AB system using differential astrometry at millimeter wavelengths. Our initial results include new absolute astrometric measurements of the proper motion, orbital motion and parallax of the {alpha} Cen system. These lead to an improved knowledge of the physical properties of both {alpha} Cen A and B. Our estimates of ALMA's relative astrometric precision suggest that we will ultimately be sensitive to planets of a few tens of Earth mass in orbits from 1 to 3au, where stable orbits are thought to exist.2021AJ....162...14Ahttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/162/14CatalogResearchIsServedByTAP VizieR generic servicerelated-toI/237 : The Washington Visual Double Star Catalog, 1996.0 (Worley+, 1996)I/311 : Hipparcos, the New Reduction (van Leeuwen, 2007)J/A+AS/107/235 : Photographic observations of visual binaries (Jasinta+, 1994)J/ApJ/687/1264 : Age estimation for solar-type dwarfs (Mamajek+, 2008)J/ApJ/771/40 : Main-sequence A, F, G, and K stars photometry (Boyajian+, 2013)J/A+A/615/A172 : alpha Cen A and B chemical composition (Morel, 2018)J/AJ/155/24 : Radial velocity & planet detectability in alpha Cen (Zhao+, 2018)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/162/14https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/162/14http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/162/14https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/162/14https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/162/14http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/162/14GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticalMillimeterdefaultJ/AJ/162/14/table6Relative astrometry of alpha Cen B with respect to ArecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintDate[1940/2020] Epoch of observationyrtime.epochdoublePA[6.5/350] Position angledegpos.posAngdoublee_PA[0.003/4.3] Uncertainty in PAdegstat.errorfloatSep[2.03/22] Separationarcsecpos.angDistance;src.orbitaldoublee_Sep[0.0003/0.5] Uncertainty in separcsecstat.errordoubleRefReference (1)meta.ref;pos.framecharJ/AJ/162/14/table7Radial velocity measurements for alpha Cen A and B from the HARPS instrumentrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintMJD[53039/58242] Modified Julian Date; MJD-2400000.5dtime.epochdoubleindexedIDStar identifier; A or Bmeta.id;meta.maincharRVel[-24.89/-21.83] Radial Velocity (1)km/sphys.veloc;pos.heliocentricdoublee_RVel[0.002/0.01] Uncertainty in RVelkm/sstat.error;spect.dopplerVelocdoubleJ/AJ/162/14/table12Ephemeris of alpha Cen A and B between 2010 and 2050recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintDate[2010/2050] Decimal yearyrtime.epochfloatCRA[14] Hour of center of mass Right Ascensionpos.eq.raCDE[60] Degree of center of mass Declinationpos.eq.decARA[14] Star A hour of Right Ascensionpos.eq.raADE[60] Star A degree of Declinationpos.eq.decBRA[14] Star B hour of Right Ascensionpos.eq.raBDE[60] Star B degree of Declinationpos.eq.decdRa[-7.68/4.12] RA offset of B relative to Aarcsecpos.angDistance;pos.eq.rafloatdEC[-16.8/9.78] Dec offset of B relative to Aarcsecpos.angDistance;pos.eq.decfloatSep[1.69/18.5] A-B separationarcsecpos.angDistance;src.orbitalfloatPA[0.13/360] A-B position angledegpos.posAngfloat