J/A+A/481/553ivo://CDS.VizieR/J/A+A/481/553doi:10.26093/cds/vizier.34810553CDSLe Bouquin J.-B.Bauvir B.Haguenauer P.Scholler M.Rantakyro F.,Menardi S.2008-05-06T22:35:27Z2008-05-06T22:33:47ZCDS support team

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

cds-question@unistra.frinterferometryOur goal is to demonstrate the potential of the interferometric AMBER instrument linked with the Very Large Telescope Interferometer (VLTI) fringe-tracking facility FINITO to derive high-precision stellar diameters. We use commissioning data obtained on the bright single star V3879 Sgr. Locking the interferometric fringes with FINITO allows us to record very low contrast fringes on the AMBER camera. By fitting the amplitude of these fringes, we measure the diameter of the target in three directions simultaneously with an accuracy of 25micro-arcseconds. We showed that V3879 Sgr has a round photosphere down to a sub-percent level. We quickly reached this level of accuracy because the technique used is independent from absolute calibration (at least for baselines that fully span the visibility null). We briefly discuss the potential biases found at this level of precision.2008A&A...481..553Lhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/481/553CatalogResearchIsServedByTAP VizieR generic servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/481/553https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/481/553http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/481/553https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/481/553https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/481/553http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/481/553GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/A+A/481/553/vis2Calibrated square visibility for 54 baselinesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintlambdaWavelengthuminstr.filter;em.wl.centralfloatMJDModifiate Julian date of observationdtime.epochdoubleStationStation of observation (1)instr.setupcharubaseline projection toward East (u, in meter)minstr.baselinedoublevbaseline projection toward Nord (v, in meter)minstr.baselinedoubleVis2[-1/1] Calibrated square visibility, Vis2=<V^2^_meas_>-biaisinstr.calibdoublee_Vis2rms uncertainty on Vis2stat.errordouble