J/A+A/621/A6ivo://CDS.VizieR/J/A+A/621/A6doi:10.26093/cds/vizier.36210006CDSOhnaka K.Hadjara M.Maluenda Berna M.Y.L.2019-01-08T14:00:01Z2018-12-19T08:11:34ZCDS support team

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

cds-question@unistra.frinterferometrygiant-starsm-starsvariable-starsWe present a near-infrared spectro-interferometric observation of the non-Mira-type, semiregular asymptotic giant branch star SW Vir. Our aim is to probe the physical properties of the outer atmosphere with spatially resolved data in individual molecular and atomic lines. We observed SW Vir in the spectral window between 2.28 and 2.31 micron with the near-infrared interferometric instrument AMBER at ESO's Very Large Telescope Interferometer (VLTI). Thanks to AMBER's high spatial resolution and high spectral resolution of 12000, the atmosphere of SW Vir has been spatially resolved not only in strong CO first overtone lines but also in weak molecular and atomic lines of H_2_O, CN, HF, Ti, Fe, Mg, and Ca. While the uniform-disk diameter of the star is 16.23+/-0.20mas in the continuum, it increases up to 22-24mas in the CO lines. Comparison with the MARCS photospheric models reveals that the star appears larger than predicted by the hydrostatic models not only in the CO lines but also even in the weak molecular and atomic lines. We found that this is primarily due to the H2O lines (but also possibly due to the HF and Ti lines) originating in the extended outer atmosphere. Although the H_2_O lines manifest themselves very little in the spatially unresolved spectrum, the individual rovibrational H_2_O lines from the outer atmosphere can be identified in the spectro-interferometric data. Our modeling suggests an H_2_O column density of 10^19^-10^20^cm^-2^ in the outer atmosphere extending out to ~2R*. Our study has revealed that the effects of the nonphotospheric outer atmosphere are present in the spectro-interferometric data not only in the strong CO first overtone lines but also in the weak molecular and atomic lines. Therefore, analyses of spatially unresolved spectra, such as for example analyses of the chemical composition, should be carried out with care even if the lines appear to be weak.2019A&A...621A...6Ohttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/621/A6CatalogResearchIsServedByTAP VizieR generic servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/621/A6https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/621/A6http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/621/A6https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/621/A6https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/621/A6http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/621/A6GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapdefaultJ/A+A/621/A6/visswvirSpectrocopically calibrated spectrum, visibilities and differential phases measured at three baselines, and closure phaserecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIndex[1/318] Indexmeta.idintWLSpectral channel indexumspect.indexdoubleFluxNormalized fluxphot.flux;arith.ratiodoubleVis1Visibility measured at baseline 1obs.paramdoublee_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 2obs.paramdoublee_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 3obs.paramdoublee_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.baselinedoublePA3Position angle of baseline 3degpos.posAngdouble