J/MNRAS/437/2303ivo://CDS.VizieR/J/MNRAS/437/2303doi:10.26093/cds/vizier.74372303CDSFuhrmann K.Chini R.Barr A.Buda L.-S.Kaderhandt L.Pozo F.,Ramolla M.2024-08-07T20:12:30Z2016-04-07T09:28:15ZCDS support team

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

cds-question@unistra.frspectroscopic-binary-starsradial-velocityThe spectroscopy of rapidly rotating binary stars occasionally encounters systems where - paradoxically - the primary is effectively hidden in the light of its secondary. Here, we report on a bright textbook example of this kind with the nearby A-type star {alpha} Lib A. Although discovered as a spectroscopic binary already in the year 1904, a radial velocity curve has never been published up to a point where the existence of the secondary became even suspicious. However, in this work, we demonstrate that {alpha} Lib A is indeed a double-lined spectroscopic binary with a rapidly rotating - and hence almost invisible - A-type primary, accompanied and predominated by a more slowly rotating late-A or early F-type secondary in an eccentric P=70.34d orbit. On account of the shallow absorption lines of the primary, uncertainties remain with its semi-amplitude and hence the exact mass ratio. Yet, with a maximal projected separation that should lie in the range 20 to 25mas, follow-up high-angular resolution observations might soon establish {alpha} Lib Aa-Ab as a visual binary, with a measure for the orbital inclination and precisely determined stellar masses.2014MNRAS.437.2303Fhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/437/2303CatalogResearchIsServedByTAP VizieR generic servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/437/2303https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/437/2303http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/437/2303https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/437/2303https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/437/2303http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/437/2303GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/MNRAS/437/2303/table1Radial velocity measurements of alpha Lib ArecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintJDJulian date (JD-2450000)dtime.epochdoubleRVAaAa component radial velocitykm/sphys.veloc;pos.heliocentricfloate_RVAarms uncertainty on RVAakm/sstat.errorfloatRVAbAb component radial velocitykm/sphys.veloc;pos.heliocentricfloate_RVAbrms uncertainty on RVAbkm/sstat.errorfloat