J/A+A/710/A383ivo://CDS.VizieR/J/A+A/710/A383CDSChamoun-Contreras J.Arcos C.Machuca N.Perez-Ramirez C.E.Cidale L.S.,Cure M.Araya I.Turis-Gallo D.Hadjara M.2026-06-29T15:15:40Z2026-06-29T16:10:29ZCDS support team

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

cds-question@unistra.frsupergiant-starsradial-velocityline-intensitiesvisible-astronomyspectroscopyMassive stars continuously enrich the surrounding interstellar medium by supplying it with stellar material driven by their powerful winds. B supergiant stars (BSGs) in particular are a type of massive star characterized by strong winds and notable photometric and spectroscopic variability. We aim to conduct a pilot study of the optical spectroscopic variability of the BSG HD 75149 between 2004 and 2025. Its extended temporal baseline and pronounced variability amplitude make it particularly well suited for investigating the physical origin of the observed short-term variability within a consistent hydrodynamical and radiative-transfer framework. We analyzed 25 nightly averaged optical spectra obtained with different instruments and telescopes, some of them with observations over several consecutive days. We measured the radial velocities (RVs) and equivalent widths (EWs) of 17 spectral lines (H, HeI, SiIII, NII, MgII, CII). We modeled the H{alpha} emission, absorption, and P-Cygni profiles using the ISOSCELES grid and the delta-slow hydrodynamic regime. H{alpha} shows variability in intervals of a few days, including P-Cygni changes, while metal lines show small RV amplitudes, consistent with pulsating oscillations. The largest variation in the mass-loss rate corresponds to an increase of a factor of 1.8 within four days. In contrast, the terminal velocity remains barely affected during the same time interval. The pronounced variation observed in hydrogen lines, in contrast with the variability of other lines, suggests that it is due to mass-loss rate episodes driven by a slow wind occurring on a timescale comparable to photometric variations. We found no evidence of a close binary companion in the sample used, but we cannot completely exclude the possibility of a wide or low-inclination companion.2026A&A...710A.383Chttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/710/A383CatalogResearchIsServedByTAP VizieR generic servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/710/A383https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/710/A383http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/710/A383https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/710/A383https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/710/A383http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/710/A383GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/A+A/710/A383/tablea1*Halpha radial velocities and equivalent widthsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintJDJulian date of observationdtime.epochdoubleRVabs? Radial velocity of the absorption componentkm/sspect.dopplerVelocfloatnullablee_RVabs? Radial velocity of the absorption component uncertaintykm/sstat.errorfloatnullableEWabs? Equivalent width of the absorption component0.1nmspect.line.eqWidthfloatnullablee_EWabs? Equivalent width of the absorption component uncertainty0.1nmstat.errorfloatnullableRVem? Radial velocity of the emission componentkm/sspect.dopplerVelocfloatnullablee_RVem? Radial velocity of the emission component uncertaintykm/sstat.errorfloatnullableEWem? Equivalent width of the emission component0.1nmspect.line.eqWidthfloatnullablee_EWem? Equivalent width of the emission component uncertainty0.1nmstat.errorfloatnullableJ/A+A/710/A383/tablea2*Day-to-day radial velocity variation by spectral line and time intervalLineSpectral line identifiermeta.id;spect.linecharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintDRVFeb13-1RV variation in Feb 2013, internal subcolumn 1km/sarith.ratefloatDRVFeb13-2RV variation in Feb 2013, internal subcolumn 2km/sarith.ratefloatDRVMar14-1RV variation in Mar 2014, internal subcolumn 1km/sarith.ratefloatDRVApr14-1RV variation in Apr 2014, internal subcolumn 1km/sarith.ratefloatDRVApr14-2RV variation in Apr 2014, internal subcolumn 2km/sarith.ratefloatDRVApr14-3RV variation in Apr 2014, internal subcolumn 3km/sarith.ratefloatDRVFeb15-1RV variation in Feb 2015, internal subcolumn 1km/sarith.ratefloatDRVFeb15-2RV variation in Feb 2015, internal subcolumn 2km/sarith.ratefloatDRVMar15-1RV variation in Mar 2015, internal subcolumn 1km/sarith.ratefloatDRVMar15-2RV variation in Mar 2015, internal subcolumn 2km/sarith.ratefloatDRVMar15-3RV variation in Mar 2015, internal subcolumn 3km/sarith.ratefloatDRVJan25-1? RV variation in Jan 2025, internal subcolumn 1 (1)km/sarith.ratefloatnullableJ/A+A/710/A383/tablea3*Day-to-day equivalent width variation by spectral line and time intervalDEWJan25_1? EW variation in Jan 2025, internal subcolumn 1 (1)0.1nmarith.rate;spect.line.eqWidthnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintLineSpectral line identifiermeta.id;spect.linecharDEWFeb13_1EW variation in Feb 2013, internal subcolumn 10.1nmarith.rate;spect.line.eqWidthDEWFeb13_2EW variation in Feb 2013, internal subcolumn 20.1nmarith.rate;spect.line.eqWidthDEWMar14_1EW variation in Mar 2014, internal subcolumn 10.1nmarith.rate;spect.line.eqWidthDEWApr14_1EW variation in Apr 2014, internal subcolumn 10.1nmarith.rate;spect.line.eqWidthDEWApr14_2EW variation in Apr 2014, internal subcolumn 20.1nmarith.rate;spect.line.eqWidthDEWApr14_3EW variation in Apr 2014, internal subcolumn 30.1nmarith.rate;spect.line.eqWidthDEWFeb15_1EW variation in Feb 2015, internal subcolumn 10.1nmarith.rate;spect.line.eqWidthDEWFeb15_2EW variation in Feb 2015, internal subcolumn 20.1nmarith.rate;spect.line.eqWidthDEWMar15_1EW variation in Mar 2015, internal subcolumn 10.1nmarith.rate;spect.line.eqWidthDEWMar15_2EW variation in Mar 2015, internal subcolumn 20.1nmarith.rate;spect.line.eqWidthDEWMar15_3EW variation in Mar 2015, internal subcolumn 30.1nmarith.rate;spect.line.eqWidthJ/A+A/710/A383/listList of fits spectrarecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNxNumber of pixels along X-axismeta.numberintNyNumber of pixels along Y-axismeta.numberintObs.dateObservation datestime.epoch;obsnullableblambda? Lower value of wavelength interval0.1nmem.wlfloatnullableBlambda? Upper value of wavelength interval0.1nmem.wlfloatnullabledlambda? Wavelength resolution0.1nmspect.resolutionfloatnullableBJD? BJD for NRES-LCO spectradtime.epochdoublenullableRVcor? Corrected RV for NRES-LCO spectrakm/sspect.dopplerVelocdoublenullableSite? Site, cpt or lsc, for NRES-LCO spectrameta.codecharsizeSize of FITS fileKibytephys.size;meta.fitsintspShow the spectrummeta.ref.urlcharFileNameName of FITS file, in subdirectory fitsmeta.id;meta.fitscharTitleTitle of the FITS file within subdirectorymeta.title;meta.fitschar