J/A+A/710/A280ivo://CDS.VizieR/J/A+A/710/A280CDSMolina F.Vos J.Bobrick A.Vuckovic M.2026-06-19T11:30:28Z2026-06-19T12:29:33ZCDS support team

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

cds-question@unistra.frspectroscopic-binary-starsorbitsvisible-astronomyLong-period binary systems containing a B-type hot subdwarf (sdB) and a main-sequence (MS) companion are thought to originate from binary interactions involving stable mass transfer from the red giant, the progenitor of the sdB, to the MS companion. However, despite the recent progress in modelling their population, some of their observed properties are not entirely understood. Because determining their orbits requires extended campaigns of high-resolution spectroscopic observations, only a limited number of long-period sdB binaries have been studied with completely determined orbital parameters. We aim to expand the current sample of long-period sdB binaries with fully determined orbital parameters through the analysis of high-resolution spectroscopic data. In addition, the atmospheric parameters of the cool companions are analysed. Increasing the number of well-characterised systems will provide valuable insights into their formation channels and main characteristics. A sample of 32 wide binary systems containing sdB stars was selected for the analysis of the radial velocity (RV) curves of both companions. The dataset consisted of high-resolution spectra obtained with the HERMES and UVES spectrographs. The orbital parameters were derived by simultaneously fitting Keplerian orbits to the RVs of the sdB and its companion. The atmospheric parameters of the cool companions were determined using the GSSP code, which analyses the master spectra of the systems with a grid of LTE atmospheric models. An additional sample of wide sdB binaries was built by cross-matching the Gaia NSS catalogue with literature catalogues of sdB candidates and spectroscopically confirmed sdB systems. The outcomes from both samples were compared with existing theoretical models to assess their consistency with current formation and evolutionary scenarios. We obtained complete orbital solutions for 32 wide sdB binaries. The orbital period distribution of the ground-based spectroscopic sample is in reasonable agreement with population-synthesis predictions, except for two outliers. The CMD further suggests that current models overpredict systems with the coolest companions, since the observed systems with BP-RP>0.3 are associated with companions hotter than 6000K. The observed period-mass ratio distribution is consistent with recent population synthesis predictions, and suggests that the unexplained second branch found in these models is mainly populated by old systems. Excluding the two long-period outliers, the data do not support a clear increase in eccentricity with orbital period, whereas the Gaia-based candidate sample shows discrepant behaviour, owing to selection effects and larger uncertainties.2026A&A...710A.280Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/710/A280CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/710/A280https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/710/A280http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/710/A280https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/710/A280https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/710/A280http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/710/A280GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/710/A280/tablea1 (Observational properties of the systems)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/710/A280/tablea1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/710/A280/tablea1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/710/A280/tablea1?GETtext/xml+votable180.050000true12.86229.359140.0055555555555555566/2785 4099 4857 6333 6911 11375 11815 12836 15514 17570 18222 18344 18701 19371 20657 23173 25153 25318 26570 26854 28388 30148 31411 31419 31683 32137 32330 32652 32655 32947 33564 34464 34518 34778 35072 35283 35707 38702 39644 45018 45186 46805 46916 47121 481441.9867573869263685e-19 3.916500758235022e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/710/A280?format=asciiOpticaldefaultJ/A+A/710/A280/tablea1Observational properties of the systemsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSimbadNameSimbad column added by the CDSmeta.idcharnullableSampleSample identifier: Ground or Gaiameta.id;src.samplecharSystemSystem name or Gaia DR3 source identifiermeta.id;meta.maincharONameOther identifiermeta.idcharRAICRSICRS right ascension (J2000)degpos.eq.ra;meta.mainDEICRSICRS declination (J2000)degpos.eq.dec;meta.mainDistDistance derived from parallaxpcpos.distancefloatSpTelSpectrograph/telescopemeta.notecharNobsNumber of observationsmeta.numbercharVmag? Johson V-band magnitudemagphot.mag;em.opt.VfloatnullableGmagGaia DR3 G-band magnitudemagphot.mag;em.optfloatBP-RPGaia DR3 BP-RP colour indexmagphot.color;em.opt.B;em.opt.RfloatRUWEGaia DR3 RUWE indexstat.errorfloatJ/A+A/710/A280/tableb1Cross-correlation intervals and linesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSystemSystem namemeta.id;meta.maincharMSintIntervals used for the MS spectral mask0.1nminstr.bandwidthcharsdBintIntervals or lines used for the sdB mask0.1nminstr.bandwidthcharJ/A+A/710/A280/tableb2Orbital parameters from Keplerian solutions of the wide hot subdwarf binary systemsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSystemSystem namemeta.id;meta.maincharPerOrbital perioddtime.periodinte_Per1-sigma error on Perdstat.errorintT0Reference epochdmeta.ref;time.epochinte_T01-sigma error on T0dstat.errorinteOrbital eccentricitysrc.orbital.eccentricityfloate_e1-sigma error on estat.errorfloatomegaArgument of periastronradsrc.orbital.periastronfloate_omega1-sigma error on omegaradstat.errorfloatKMSSemi-amplitude of the MS componentkm/sphys.veloc;src.orbitalfloate_KMS1-sigma error on KMSkm/sstat.errorfloatKsdBSemi-amplitude of the sdB componentkm/sphys.veloc;src.orbitalfloate_KsdB1-sigma error on KsdBkm/sstat.errorfloatgamMSSystemic velocity of the MS componentkm/sphys.velocfloate_gamMS1-sigma error on gamMSkm/sstat.errorfloatgamsdBSystemic velocity of the sdB componentkm/sphys.velocfloate_gamsdB1-sigma error on gamsdBkm/sstat.errorfloatqMass ratiophys.massfloate_q1-sigma error on qstat.errorfloatJ/A+A/710/A280/tableb3*Atmospheric parameters of cool companionse_vsiniLower 1-sigma error on vsinikm/sstat.error;phys.veloc.rotatintE_vsiniUpper 1-sigma error on vsinikm/sstat.error;stat.maxintDilDilution factorstat.fit.paramfloate_DilLower 1-sigma error on Dilstat.errorfloatE_DilUpper 1-sigma error on Dilstat.error;stat.maxfloatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSampleSample identifier: Ground or GaiaObsmeta.id;src.samplecharSystemSystem namemeta.id;meta.maincharTeffEffective temperatureKphys.temperature.effectiveinte_TeffLower 1-sigma error on TeffKstat.error;phys.temperature.effectiveintE_TeffUpper 1-sigma error on TeffKstat.error;stat.maxint[M/H]Metallicityphys.abund.Zfloate_[M/H]Lower 1-sigma error on [M/H]stat.error;phys.abundfloatE_[M/H]Upper 1-sigma error on [M/H]stat.error;stat.maxfloatloggSurface gravitylog(cm.s**-2)phys.gravityfloate_loggLower 1-sigma error on logglog(cm.s**-2)stat.errorfloatE_loggUpper 1-sigma error on logglog(cm.s**-2)stat.error;stat.maxfloatvsiniProjected rotational velocitykm/sphys.veloc.rotatint