Mid-infrared diameter of W HyaJ/A+A/530/A120ivo://CDS.VizieR/J/A+A/530/A120doi:10.26093/cds/vizier.35300120CDSZhao-Geisler R.Quirrenbach A.Koehler R.Lopez B.Leinert C.2017-07-05T07:00:15Z2011-05-23T08:37:13ZCDS support teamCDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, Francecds-question@unistra.frvariable-starsstellar-radiiinfrared-sourcesMid-infrared (N-band) interferometric data of W Hya were obtained with MIDI/VLTI between April 2007 and September 2009, covering nearly three pulsation cycles. The spectrally dispersed visibility data of all 75 observations were analyzed by fitting a circular fully limb-darkened disk (FDD) model to all data and individual pulsation phases. Asymmetries were studied with an elliptical FDD. Modeling results in an apparent angular FDD diameter of W Hya of about (80+/-1.2)mas (7.8AU) between 8 and 10 micron, which corresponds to an about 1.9 times larger diameter than the photospheric one. The diameter gradually increases up to (105+/-1.2)mas (10.3AU) at 12 micron. In contrast, the FDD relative flux fraction decreases from (0.85+/-0.02) to (0.77+/-0.02), reflecting the increased flux contribution from a fully resolved surrounding silicate dust shell. The asymmetric character of the extended structure could be confirmed. An elliptical FDD yields a position angle of (11+/-20)deg and an axis ratio of (0.87+/-0.07). A weak pulsation dependency is revealed with a diameter increase of (5.4+/-1.8)mas between visual minimum and maximum, while detected cycle-to-cycle variations are smaller.2011A&A...530A.120Zhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/530/A120CatalogResearchIsServedByTAP VizieR generic servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/530/A120https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/530/A120http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/530/A120https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/530/A120https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/530/A120http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/530/A120GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapInfrareddefault
J/A+A/530/A120/table1Observation logQFQuality flag (2)meta.code.qualcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintDateObservation datetime.epoch;obsnullableATAT station (1)meta.id;instrcharDispDispersive element (grism or prism)meta.codecharBProjected baseline lengthminstr.baselinefloatPA[-13/131] Position angle of the projected baseline on the skydegpos.posAng;obs.fieldfloatPhasePhasetime.phasefloatSeq? Sequential number for visibility used in data.dat filemeta.recordintnullablePlotSimbad column added by the CDSmeta.ref.urlchar