J/ApJ/948/34ivo://CDS.VizieR/J/ApJ/948/34doi:10.26093/cds/vizier.19480034CDSSigut T.A.A.Ghafourian N.R.2025-08-01T20:11:25Z2025-07-17T08:11:22ZCDS support team

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

cds-question@unistra.frbe-starsstellar-spectral-typesvisible-astronomyh-alpha-photometryspectroscopyUsing a sample of 92 Galactic Be stars, we compare inclination angles (the angle between a star's rotation axis and the line of sight) determined from H{alpha} emission-line profile fitting to those determined by the spectroscopic signature of gravitational darkening. We find good agreement: 70% of the sample (64 out of 92 stars) is consistent with zero difference between the two methods using 1{sigma} errors, and there is a strong linear correlation coefficient between the two methods of r=+0.63+/-0.05. There is some evidence that the H{alpha} profile fitting method overestimates the inclination angle for i<~25{deg}, perhaps due to the neglect of incoherent electron scattering on the H{alpha} line widths, while the gravitational darkening method underestimates the inclination angle for i>~70{deg}, perhaps due to the neglect of disk radiative transfer effects on the optical spectrum. Overall, it is demonstrated that a single H{alpha} spectrum of modest resolution and SNR can be used to extract a useful estimate for the inclination angle of an individual Be star. This allows equatorial rotation velocities for individual Be stars to be derived from vsini measurements and will allow Be stars to be used to search for correlated spin axes in young, open clusters if unbiased (with respect to inclination) samples of Be stars are used.2023ApJ...948...34Shttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/948/34CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/ApJS/99/135 : Rotation and Spectral Peculiarities (Abt+ 1995)J/A+A/440/305 : Fundamental param. of fast-rotating B stars (Fremat+, 2005)J/A+A/451/1053 : Fundamental parameters of Be stars (Fremat+, 2006)J/A+A/459/137 : Bright Be shell stars (Rivnius+, 2006)J/ApJ/814/159 : H{alpha} interferometric visibilities of o Aqr (Sigut+, 2015)J/A+A/595/A132 : Be star rotational velocities distribution (Zorec+, 2016)J/A+A/618/A109 : Seismic global parameters of 372 KIC (Mosser+, 2018)J/MNRAS/488/572 : Bayesian hierarchical inferred incl. (Kuszlewicz+, 2019)J/ApJ/903/99 : Stellar spins in the open cluster NGC 2516 (Healy+, 2020)J/A+A/645/A124 : Inclinations for RGBs from Kepler (Gehan+, 2021)J/ApJ/923/23 : Stellar spins in the Pleiades, Praesepe & M35 (Healy+, 2021)http://basebe.obspm.fr/basebe/ : Be Star Spectra database (BeSS)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/948/34https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/948/34http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/948/34https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/948/34https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/948/34http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/948/34GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/948/34/table1 (Be star sample)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/948/34/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/948/34/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/948/34/table1?GETtext/xml+votable180.050000true1.610572264.19615810.0055555555555555566/405 463 472 474 1011 1586 1748 1769 1784 2017 2775 2849 2884 3030 3067 3491 9686 9836 12659 12988 13017 13042 13268 13292 13687 13701 13721 14396 14555 14622 14631 14638 15365 15375 18915 19017 19202 19402 20551 20609 20923 21313 21447 21515 22054 22334 22503 22579 22895 22906 22911 23775 23963 24142 24183 26672 30330 30444 30722 31759 34199 34896 37253 37330 37364 37887 39397 39671 39704 39863 40221 40242 41171 41740 41866 41939 41943 42273 42279 42486 43062 43365 43407 43531 43689 46081 47009 47021 47056 47246 48534https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/948/34?format=asciiOpticaldefaultJ/ApJ/948/34/table1Be star samplerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHD[144/224686] HD catalog identifiermeta.id;meta.mainintNameCommon star namemeta.idcharSpTSpectral Type from SIMBADsrc.spTypechariHa[12/88] Stellar inclination, H{alpha} line fittingdegsrc.orbital.inclination;em.line.Halphainte_iHa[5/17] Uncertainty (1{sigma}) in iHadegstat.error;src.orbital.inclination;em.line.HalphaintiGD[13/89] Stellar inclination, gravitational darkening [i] (1)degsrc.orbital.inclination;phot.limbDarkinte_iGD[7/22] Uncertainty (1{sigma}) in iGD (1)degstat.error;src.orbital.inclination;phot.limbDarkintShell[1/12.02] Shell parameter, this work (2)phot.flux;arith.ratiofloatV/R[1/1.2] Ratio, V(iolet) and R(ed) emission peak fluxes, this workphot.flux;arith.ratiofloatvsini[40/603] Projected rotational velocity (1)km/sphys.veloc.rotatinte_vsini[3/55] Uncertainty (1{sigma}) in vsini (1)km/sstat.error;phys.veloc.rotatintSimbadSimbad column added by the CDSmeta.ref.urlcharSourceSource (3)meta.id;obscharNotesNote(s) (4)meta.notechar_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