J/A+A/620/A85ivo://CDS.VizieR/J/A+A/620/A85doi:10.26093/cds/vizier.36200085CDSOomen G.M.Van Winckel H.Pols O.Nelemans G.Escorza A.Manick R.,Kamath D.Waelkens C.2019-01-07T09:22:56Z2018-12-04T11:01:09ZCDS support team

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

cds-question@unistra.frspectroscopic-binary-starsradial-velocityBinary post-asymptotic giant branch (post-AGB) stars are thought to be the products of a strong but poorly-understood interaction during the AGB phase. The aim of this contribution is to update the orbital elements of a sample of galactic post-AGB binaries observed in a long-term radial-velocity monitoring campaign, by analysing these systems in a homogeneous way. Radial velocities are computed from high signal-to-noise spectra by use of a cross-correlation method. The radial-velocity curves are fitted by using both a least-squares algorithm and a Nelder-Mead simplex algorithm. We use a Monte Carlo method to compute uncertainties on the orbital elements. The resulting mass functions are used to derive a companion mass distribution by optimising the predicted to the observed cumulative mass-function distributions, after correcting for observational bias. As a result, we derive and update orbital elements for 33 galactic post-AGB binaries, among which 3 are new orbits. The orbital periods of the systems range from 100 to about 3000 days. Over 70 percent (23 out of 33) of our binaries have significant non-zero eccentricities ranging over all periods. Their orbits are non-circular despite the fact that the Roche-lobe radii are smaller than the maximum size of a typical AGB star and tidal circularisation should have been strong when the objects were on the AGB. We derive a distribution of companion masses that is peaked around 1.09M_{sun}_ with a standard deviation of 0.62M_{sun}_. The large spread in companion masses highlights the diversity of post-AGB binary systems. Post-AGB binaries are often chemically peculiar, showing in their photospheres the result of an accretion process of circumstellar gas devoid of refractory elements. We find that only post-AGB stars with high effective temperatures (>5500K) in wide orbits are depleted in refractory elements, suggesting that re-accretion of material from a circumbinary disc is an ongoing process. It appears, however, that depletion is inefficient for the closest orbits irrespective of the actual surface temperature.2018A&A...620A..85Ohttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/620/A85CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/A+A/597/A129 : Galactic RV Tauri stars velocities (Manick+, 2017)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/620/A85https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/620/A85http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/620/A85https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/620/A85https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/620/A85http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/620/A85GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapdefaultJ/A+A/620/A85/table1Updated orbital elementse_gammarms uncertainty on gammakm/sstat.errorfloatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSeqSequential numbermeta.recordintNameStar namemeta.id;meta.maincharPerPerioddtime.perioddoublee_Perrms uncertainty on Perdstat.errorfloatEccEccentricitysrc.orbital.eccentricityfloate_Eccrms uncertainty on Eccstat.errorfloatT0? Time of periastron passagedtime.epochdoublenullablee_T0? rms uncertainty on T0dstat.errorfloatnullableomega? Argument of periastrondegsrc.orbital.periastronfloatnullablee_omega? rms uncertainty on omegadegstat.errorfloatnullableK1K1 velocitykm/sphys.velocfloate_K1rms uncertainty on K1km/sstat.errorfloatgammagamma velocitykm/sphys.velocfloatRefReferences (1)meta.refcharFileNameName of the file with RV data in subdirectory rvmeta.id;meta.filecharVCShow the Radial Velocity curvesmeta.ref.urlchar