J/MNRAS/511/4724ivo://CDS.VizieR/J/MNRAS/511/4724doi:10.26093/cds/vizier.75114724CDSHadjara M.Petrov R.G.Jankov S.Cruzalebes P.Boskri A.Spang A.,Lagarde S.He J.Chen X.Nitschelm C.de Almeida E.S.GPereira G.,Michael E.A.Gao Q.Wang W.Reyes I.Arcos C.Araya I.Cure M.2024-08-22T20:15:17Z2022-03-15T09:20:14ZCDS support team

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

cds-question@unistra.frvariable-starsinterferometryDifferential Interferometry allows to obtain the differential visibility and phase, in addition to the spectrum. The differential phase contains important information about the structure and motion of stellar photosphere such as stellar spots and non-radial pulsations, and particularly the rotation. Thus, this interferometric observable strongly helps to constrain the stellar fundamental parameters of fast rotators. The spectroastrometry mainly uses the photocentre displacements, which is a first approximation of the differential phase, and is applicable only for unresolved or marginally objects. We study here the sensitivity of relevant stellar parameters to the simulated photocentres using the scirocco code: a semi-analytical algorithm dedicated to fast rotators, applied to two theoretical modelling stars based on Achernar and Regulus, in order to classify the importance of these parameters and their impact on the modelling. We compare our simulations with published VLTI/AMBER data. This work sets the limits of application of photocentre displacements to fast rotators, and under which conditions we can use the photocentres and/or the differential phase, through a pre-established physical criterion. To validate our theoretical study, we apply our method of analysis on observed data of the edge-on fast rotator Regulus. For unresolved targets, with a visibility V~1, the photocentre can constrain the main stellar fundamental parameters of fast rotators, whereas from marginally resolved objects (0.8<=V<1), mainly the rotation axis position angle (PA_rot_) can be directly deduced from the vectorial photocentre displacement, which is very important for young cluster studies.2022MNRAS.511.4724Hhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/511/4724CatalogResearchIsServedByTAP VizieR generic servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/511/4724https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/511/4724http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/511/4724https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/511/4724https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/511/4724http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/511/4724GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapdefaultJ/MNRAS/511/4724/alf_leoSpectrocopically calibrated spectrum, visibilities and differential phases measured at three baselines, and closure phasePA3Position angle of baseline 3degpos.posAngdoublerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIndex[1/1014]+ Indexmeta.idintprimaryindexedWLSpectral channel indexumem.wldoubleFluxNormalized fluxphot.flux;arith.ratiodoublee_FluxError in Normalized fluxstat.error;phot.fluxdoubleVis1Visibility measured at baseline 1phot.flux;arith.ratiodoublee_Vis1Error in visibility at baseline 1stat.errordoubleDP1Differential phase measured at baseline 1degtime.phase;arith.diffdoublee_DP1Error in differential phase at baseline 1degstat.errordoubleVis2Visibility measured at baseline 2phot.flux;arith.ratiodoublee_Vis2Error in visibility at baseline 2stat.errordoubleDP2Differential phase measured at baseline 2degtime.phase;arith.diffdoublee_DP2Error in differential phase at baseline 2degstat.errordoubleVis3Visibility measured at baseline 3phot.flux;arith.ratiodoublee_Vis3Error in visibility at baseline 3stat.errordoubleDP3Differential phase measured at baseline 3degtime.phase;arith.diffdoublee_DP3Error in differential phase at baseline 3degstat.errordoubleCPClosure phasedegtime.phasedoublee_CPError in closure phasedegstat.errordoubleBP1Projected baseline 1minstr.baselinedoublePA1Position angle of baseline 1degpos.posAngdoubleBP2Projected baseline 2minstr.baselinedoublePA2Position angle of baseline 2degpos.posAngdoubleBP3Projected baseline 3minstr.baselinedouble