J/A+A/600/A82ivo://CDS.VizieR/J/A+A/600/A82doi:10.26093/cds/vizier.36000082CDSGrin N.J.Ramirez-Agudelo O.H.de Koter A.Sana H.Puls J.Brott I.,Crowther P.A.Dufton P.L.Evans C.J.Graefener G.Herrero A.,Langer N.Lennon D.J.van Loon J.T.Markova N.de Mink S.E.,Najarro F.Schneider F.R.N.Taylor W.D.Tramper F.Vink J.S.,Walborn W.R.2017-10-13T15:41:18Z2017-04-04T07:54:46ZCDS support team

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

cds-question@unistra.frmagellanic-cloudso-starschemical-abundancesTheoretically, rotation-induced chemical mixing in massive stars has far reaching evolutionary consequences, affecting the sequence of morphological phases, lifetimes, nucleosynthesis, and supernova characteristics. Using a sample of 72 presumably single O-type giants to supergiants observed in the context of the VLT-FLAMES Tarantula Survey (VFTS), we aim to investigate rotational mixing in evolved core-hydrogen burning stars initially more massive than 15M_{sun}_ by analysing their surface nitrogen abundances. Using stellar and wind properties derived in a previous VFTS study we computed synthetic spectra for a set of up to 21 N II-V lines in the optical spectral range, using the non-LTE atmosphere code FASTWIND. We constrained the nitrogen abundance by fitting the equivalent widths of relatively strong lines that are sensitive to changes in the abundance of this element. Given the quality of the data, we constrained the nitrogen abundance in 38 cases; for 34 stars only upper limits could be derived, which includes almost all stars rotating at vrot>200km/s. We analysed the nitrogen abundance as a function of projected rotation rate vrot and confronted it with predictions of rotational mixing. We found a group of N-enhanced slowly-spinning stars that is not in accordance with predictions of rotational mixing in single stars. Among O-type stars with (rotation-corrected) gravities less than logg_c_=3.75 this group constitutes 30-40 percent of the population. We found a correlation between nitrogen and helium abundance which is consistent with expectations, suggesting that, whatever the mechanism that brings N to the surface, it displays CNO-processed material. For the rapidly-spinning O-type stars we can only provide upper limits on the nitrogen abundance, which are not in violation with theoretical expectations. Hence, the data cannot be used to test the physics of rotation induced mixing in the regime of high spin rates. While the surface abundances of 60-70 percent of presumed single O-type giants to supergiants behave in conformity with expectations, at least 30-40 percent of our sample can not be understood in the current framework of rotational mixing for single stars. Even though we have excluded stars showing radial velocity variations, of our sample may have remained contaminated by post-interaction binary products. Hence, it is plausible that effects of binary interaction need to be considered to understand their surface properties. Alternatively, or in conjunction, the effects of magnetic fields or alternative mass-loss recipes may need to be invoked.2017A&A...600A..82Ghttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/600/A82CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/A+A/530/A108 : VLT-FLAMES Tarantula Survey (Evans+, 2011)J/A+A/550/A107 : RV catalogue of O stars in 30 Doradus (Sana+, 2013)J/A+A/550/A108 : DIB in VLT-FLAMES Tarantula Survey (van Loon+, 2013)J/A+A/550/A109 : VLT-FLAMES Tarantula Survey: vsini measures (Dufton+ 2013)J/A+A/558/A134 : VLTS. 30 Dor luminous stars (Doran+, 2013)J/A+A/560/A29 : O-stars in VLT-FLAMES Tarantula Survey (Ramirez-Agudelo+ 2013)J/A+A/564/A39 : VLTS. OVz stars in 30 Dor (Sabin-Sanjulian+, 2014)J/A+A/564/A40 : VLTS. O-type stellar content of 30 Dor (Walborn+, 2014)J/A+A/564/L7 : VLT-FLAMES Tarantula Survey: VFTS 822 (Kalari+, 2014)J/A+A/574/A13 : VLTS. B-type stars classification and RV (Evans+, 2015)J/A+A/575/A70 : VLT-FLAMES Tarantula Survey: B supergiants (McEvoy+, 2015)J/A+A/580/A93 : VLTS. B stars multiplicity (Dunstall+, 2015)J/A+A/600/A81 : VLTS. 30Dor O giants and supergiants (Ramirez-Agudelo+, 2017)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/600/A82https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/600/A82http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/600/A82https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/600/A82https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/600/A82http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/600/A82GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/600/A82/tablea1 (Table of results for the O-type giants and supergiants)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/600/A82/tablea1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/600/A82/tablea1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/600/A82/tablea1?GETtext/xml+votable180.050000true84.287-69.12233060.005555555555555556Cone search capability for table J/A+A/600/A82/tablea2 (Table of results for the O-type stars without assigned luminosity class)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/600/A82/tablea2?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/600/A82/tablea2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/600/A82/tablea2?GETtext/xml+votable180.050000true84.3659583-69.13411110.0055555555555555566/33094https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/600/A82?format=asciidefaultJ/A+A/600/A82/table2Equivalent widthsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintVFTS[16/843] VLT-FLAMES Tarantula Survey identifiermeta.id;meta.mainintEWNII3995? Equivalent width of the NII3995 line (1)0.1pmspect.line.eqWidthfloatnullablee_EWNII3995? Error on EWNII3995 line (1)0.1pmstat.errorfloatnullableEWNII4630? Equivalent width of the NII4630 line (1)0.1pmspect.line.eqWidthfloatnullablee_EWNII4630? Error on EWNII4630 line (1)0.1pmstat.errorfloatnullableEWNIII4097? Equivalent width of the NIII4097 line (1) (2)0.1pmspect.line.eqWidthfloatnullablee_EWNIII4097? Error on EWNIII4097 line (1)0.1pmstat.errorfloatnullableEWNIII4195? Equivalent width of the NIII4195 line (1)0.1pmspect.line.eqWidthfloatnullablee_EWNIII4195? Error on EWNIII4195 line (1)0.1pmstat.errorfloatnullableEWNIII4379? Equivalent width of the NIII4379 line (1)0.1pmspect.line.eqWidthfloatnullablee_EWNIII4379? Error on EWNIII4379 line (1)0.1pmstat.errorfloatnullableEWNIII4511? Equivalent width of the NIII4511 line (1)0.1pmspect.line.eqWidthfloatnullablee_EWNIII4511? Error on EWNIII4511 line (1)0.1pmstat.errorfloatnullableEWNIII4515? Equivalent width of the NIII4515 line (1)0.1pmspect.line.eqWidthfloatnullablee_EWNIII4515? Error on EWNIII4515 line (1)0.1pmstat.errorfloatnullableEWNIII4518? Equivalent width of the NIII4518 line (1)0.1pmspect.line.eqWidthfloatnullablee_EWNIII4518? Error on EWNIII4518 line (1)0.1pmstat.errorfloatnullableEWNIII4523? Equivalent width of the NIII4523 line (1)0.1pmspect.line.eqWidthfloatnullablee_EWNIII4523? Error on EWNIII4523 line (1)0.1pmstat.errorfloatnullableEWNIII4535? Equivalent width of the NIII4535 line (1)0.1pmspect.line.eqWidthfloatnullablee_EWNIII4535? Error on EWNIII4535 line (1)0.1pmstat.errorfloatnullableEWNIII4634? Equivalent width of the NIII4634 line (1)0.1pmspect.line.eqWidthfloatnullablee_EWNIII4634? Error on EWNIII4634 line (1)0.1pmstat.errorfloatnullableEWNIII4640? Equivalent width of the NIII4640 line (1)0.1pmspect.line.eqWidthfloatnullablee_EWNIII4640? Error on EWNIII4640 line (1)0.1pmstat.errorfloatnullableEWNIIIqua? Combined equivalent width of the NIII4511-4515-4518 lines (1)0.1pmspect.line.eqWidthfloatnullablee_EWNIIIqua? Error on EWNIIIqua (1)0.1pmstat.errorfloatnullableEWNIV4058? Equivalent width of the NIV4058 line (1)0.1pmspect.line.eqWidthfloatnullablee_EWNIV4058? Error on EWNIV4058 line (1)0.1pmstat.errorfloatnullableEWNV4603? Equivalent width of the NV4603 line (1)0.1pmspect.line.eqWidthfloatnullablee_EWNV4603? Error on EWNV4603 line (1)0.1pmstat.errorfloatnullableEWNV4619? Equivalent width of the NV4619 line (1)0.1pmspect.line.eqWidthfloatnullablee_EWNV4619? Error on EWNV4619 line (1)0.1pmstat.errorfloatnullableJ/A+A/600/A82/tablea1Table of results for the O-type giants and supergiantse_epsN? Error on surface nitrogen abundancestat.errorfloatnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintVFTS[16/843] VLT-FLAMES Tarantula Survey identifiermeta.id;meta.mainintn_VFTS[*] Note on VFTS (1)meta.notecharSpTypeMorphological classification by Walborn et al. (2014, Cat. J/A+A/564/A40)src.spTypecharvsiniProjected rotational velocity (2)km/sphys.veloc.rotatintl_epsNUpper limit flag on epsNmeta.code.errorcharepsNSurface nitrogen abundance (=log(N_N/N_H)+12, see equation 1)phys.abundfloatNlines? Number of lines used for measurement (3)meta.numberintnullableYHeSurface Helium mass fraction (2)phys.abund.YfloatloggcLogarithmic surface gravity corrected for rotation (2)log(cm.s**-2)phys.gravityfloatTeffEffective Temperature in kilo Kelvin (2)kKphys.temperature.effectivefloatlogLLogarithmic luminosity in terms of solar (2)log(solLum)phys.luminosityfloatMassMass estimate in solar masses (2)(4)solMassphys.massintEW[*] * indicates equivalent width in table2meta.notecharPropDisplay the steller properties form Paper XXIV (Cat. J/A+A/600/A81)meta.ref.urlcharSimbadSimbad column added by the CDSmeta.ref.urlchar_RARight Ascension (J2000) from SIMBAD (not part of the original data)degpos.eq.ra;meta.main_DEDeclination (J2000) from SIMBAD (not part of the original data)degpos.eq.dec;meta.mainJ/A+A/600/A82/tablea2Table of results for the O-type stars without assigned luminosity classrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintVFTS[16/843] VLT-FLAMES Tarantula Survey identifiermeta.id;meta.mainintn_VFTS[*] Note on VFTS (1)meta.notecharSpTypeMorphological classification by Walborn+ (2014)src.spTypecharvsiniProjected rotational velocity (2)km/sphys.veloc.rotatintepsNSurface nitrogen abundance (= log(N_N/N_H)+12, see equation 1)phys.abundfloatl_epsNUpper limit on the nitrogen abundancemeta.code.errorchare_epsN? Error on surface nitrogen abundancestat.errorfloatnullableNlines? Number of lines used for measurement (3)meta.numberintnullableloggcLogarithmic surface gravity corrected forlog(cm.s**-2)phys.gravityfloatEW[*] * indicates equivalent widths in table2meta.notecharPropDisplay the steller properties form Paper XXIV (Cat. J/A+A/600/A81)meta.ref.urlcharSimbadSimbad column added by the CDSmeta.ref.urlchar_RARight Ascension (J2000) from SIMBAD (not part of the original data)degpos.eq.ra;meta.main_DEDeclination (J2000) from SIMBAD (not part of the original data)degpos.eq.dec;meta.main