J/A+A/639/A81ivo://CDS.VizieR/J/A+A/639/A81doi:10.26093/cds/vizier.36390081CDSBurssens S.Simon-Diaz S.Bowman D.M.Holgado G.Michielsen M.,De Burgos A.Castro N.Barba R.H.Aerts C.2021-02-02T09:04:55Z2020-11-20T08:47:38ZCDS support team

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

cds-question@unistra.frob-starsasteroseismologyspectroscopyThe lack of high-precision long-term continuous photometric data for large samples of stars has impeded the large-scale exploration of pulsational variability in the OB star regime. As a result, the candidates for in-depth asteroseismic modelling have remained limited to a few dozen dwarfs. The TESS nominal space mission has surveyed the southern sky, including parts of the galactic plane, yielding continuous data across at least 27d for hundreds of OB stars. We aim to couple TESS data in the southern sky with ground-based spectroscopy to study the variability in two dimensions, mass and evolution. We focus mainly on the presence of coherent pulsation modes that may or may not be present in the predicted theoretical instability domains and unravel all frequency behaviour in the amplitude spectra of the TESS data. We compose a sample of 98 OB-type stars observed by TESS in Sectors 1-13 and with available multi-epoch, high-resolution spectroscopy gathered by the IACOB and OWN surveys. We present the short-cadence 2 min light curves of dozens of OB-type stars, which have one or more spectra in the IACOB or OWN database. Based on these light curves and their Lomb-Scargle periodograms, we performed variability classification and frequency analysis. We placed the stars in the spectroscopic Hertzsprung-Russell diagram to interpret the variability in an evolutionary context. We deduce the diverse origins of the mmag-level variability found in all of the 98 OB stars in the TESS data. We find among the sample several new variable stars, including three hybrid pulsators, three eclipsing binaries, high frequency modes in a Be star, and potential heat-driven pulsations in two Oe stars. We identify stars for which future asteroseismic modelling is possible, provided mode identification is achieved. By comparing the position of the variables to theoretical instability strips, we discuss the current shortcomings in non-adiabatic pulsation theory and the distribution of pulsators in the upper Hertzsprung-Russell diagram.2020A&A...639A..81Bhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/639/A81CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toIV/38 : TESS Input Catalog - v8.0 (TIC-8) (Stassun+, 2019)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/639/A81https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/639/A81http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/639/A81https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/639/A81https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/639/A81http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/639/A81GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/639/A81/table2 (Overview of OB-type stars with available TESS photometry and IACOB/OWN spectroscopy with spectral type O4 to B3 considered in this work)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/639/A81/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/639/A81/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/639/A81/table2?GETtext/xml+votable180.050000true166.8867369-59.96352890.0055555555555555566/16490 17754 20613 20759 20782 20834 20847 20860 20862 20915 21233 21401 21432 21436 21438-21439 21635 21638 21647 21655-21656 21729 22173 22211 22223 22240 22243 22249 22253 22258 22269 22730 22805 22854 22862 22884 22893 23007 23281 23442 23637 23701 23717 23764 23769 23774 23780 23851 24132 28809 37861 37863 37870 37897 37926 37930-37931 38026 39254 39327 39853 39894 39907 39916 39922 39930 40617 41686 41750 42228 42303 42383 42394 42416-42417 42456 42458 42470-42471 43034 43062https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/639/A81?format=asciidefaultJ/A+A/639/A81/table2Overview of OB-type stars with available TESS photometry and IACOB/OWN spectroscopy with spectral type O4 to B3 considered in this workrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSampleSample code (G1)meta.code;src.sampleintNameStar namemeta.id;meta.maincharSpTypeSpectral typesrc.spTypecharSpClassSpectral classsrc.spTypecharlogTeff? Effective temperaturelog(K)phys.temperature.effectivefloatnullablelogLs? Spectroscopic luminosity (where Ls=Teff^4^/g) (2)log(Sun)stat.fit.paramfloatnullablevsini? Rotational velocitykm/sphys.veloc.rotatintnullablevmac? Macroturbulent velocitykm/sphys.veloc.microTurbintnullableNspNumber of available spectrameta.numberintVarTypespSpectral variability type (G3)meta.code;src.varcharVarTypeTTESS variability type (4)meta.notecharSimbadSimbad 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/639/A81/tablea1Summary of the frequency analysis of the stars considered in this workrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSampleSample code (G1)meta.code;src.sampleintNameStar Namemeta.id;meta.maincharTICTIC identification numbermeta.idlongn_TIC[+] Note on TIC (2)meta.notechar1/DTFrequency resolution of the amplitude spectra, defined as the reciprocal of the time-spand**-1spect.resolutionfloatWindowNoise windowd**-1instr.det.noisefloatnudomDominant frequencyd**-1em.freqdoublee_nudomrms uncertainty on nudomd**-1stat.errordoubleAdomAmplitude of dominant frequencymmagphot.magfloate_Adomrms uncertainty on Adommmagstat.errorfloatS/NSignal-to-noise ratiostat.snrfloatVarTypespSpectral variability type (G3)meta.code;src.varcharNotesNotes (4)meta.notecharJ/A+A/639/A81/tablea2Detailed frequency analysis of multiperiodic pulsators for 26 starsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSample[A-F] Sample code (1)meta.code;src.samplecharNameStar namemeta.id;meta.maincharFreqNameFrequency designationmeta.notecharFreqFrequency valued**-1em.freqfloate_Freqrms uncertainty on Freqd**-1stat.errorfloatAmpAmplitude of variation of Freqmmagarith.rate;phot.magfloate_Amprms uncertainty on Ampmmagstat.errorfloatphi[-0.5/0.5] Phasetime.phasefloate_phirms uncertainty on phistat.errorfloatS/NSignal-to-noise ratiostat.snrfloatNotesNotes (2)meta.notechar