J/A+A/615/A8ivo://CDS.VizieR/J/A+A/615/A8doi:10.26093/cds/vizier.36150008CDSDe Beck E.Olofsson H.2018-08-02T07:42:27Z2018-07-03T07:25:11ZCDS support team

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

cds-question@unistra.frgiant-starsspectroscopyOur current insights into the circumstellar chemistry of asymptotic giant branch (AGB) stars are largely based on studies of carbon-rich stars and stars with high mass-loss rates. In order to expand the current molecular inventory of evolved stars we present a spectral scan of the nearby, oxygen-rich star R Dor, a star with a low mass-loss rate (~2x10^-7^M_{sun}_/yr). We carried out a spectral scan in the frequency ranges 159.0-321.5GHz and 338.5-368.5GHz (wavelength range 0.8-1.9mm) using the SEPIA/Band-5 and SHeFI instruments on the APEX telescope and we compare it to previous surveys, including one of the oxygen-rich AGB star IK Tau, which has a high mass-loss rate (~5x10^-6^M_{sun}_/yr). The spectrum of R Dor is dominated by emission lines of SO_2_ and the different isotopologues of SiO. We also detect CO, H_2_O, HCN, CN, PO, PN, SO, and tentatively TiO_2_, AlO, and NaCl. Sixteen out of approximately 320 spectral features remain unidentified. Among these is a strong but previously unknown maser at 354.2GHz, which we suggest could pertain to H_2_SiO, silanone. With the exception of one, none of these unidentified lines are found in a similarly sensitive survey of IK Tau performed with the IRAM 30 m telescope. We present radiative transfer models for five isotopologues of SiO (^28^SiO, ^29^SiO, ^30^SiO, Si^17^O, Si^18^O), providing constraints on their fractional abundance and radial extent. We derive isotopic ratios for C, O, Si, and S and estimate that, based on our results for ^17^O/^18^O, R Dor likely had an initial mass in the range 1.3-1.6M_{sun}_, in agreement with earlier findings based on models of H_2_O line emission. From the presence of spectral features recurring in many of the measured thermal and maser emission lines we tentatively identify up to five kinematical components in the outflow of R Dor, indicating deviations from a smooth, spherical wind.2018A&A...615A...8Dhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/615/A8CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/615/A8https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/615/A8http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/615/A8https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/615/A8https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/615/A8http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/615/A8GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/615/A8/list (Information on fist spectrum)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/615/A8/list?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/615/A8/list?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/615/A8/list?GETtext/xml+votable180.050000true69.18991-62.077220.005555555555555556Associated datahttps://cdsarc.cds.unistra.fr/assocdata/?obs_collection=J/A+A/615/A86/33233https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/615/A8?format=asciidefaultJ/A+A/615/A8/listInformation on fist spectrumrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000Right Ascension of center (J2000)degpos.eq.ra;meta.mainDEJ2000Declination of center (J2000)degpos.eq.dec;meta.mainNxNumber of pixels along X-axismeta.numberintObs.dateObservation date (YYYY-MM-DDThh:mm:ss.sss)time.epoch;obscharbFreqLower value of frequency intervalHzem.freq;stat.mindoubleBFreqUpper value of frequency intervalHzem.freq;stat.maxdoubledFreqspectral resolutionHzspect.resolutionintsizeSize of FITS fileKibytephys.size;meta.fitsintspShow the spectrummeta.ref.urlcharFileNameName of FITS file, in subdirectory spmeta.id;meta.fitscharTitleTitle of the FITS filemeta.title;meta.fitscharAssocDataAssociated Data web pagemeta.bib.pagechar