J/ApJ/801/67ivo://CDS.VizieR/J/ApJ/801/67doi:10.26093/cds/vizier.18010067CDSXin Y.Ferraro F.R.Lu P.Deng L.Lanzoni B.Dalessandro E.,Beccari G.2015-09-02T11:50:24Z2015-08-06T13:46:35ZCDS support team

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

cds-question@unistra.frmultiple-starsstellar-massesglobular-star-clustersastronomical-modelsTwo separated sequences of blue straggler stars (BSSs) have been revealed by Ferraro et al. (2009Natur.462.1028F) in the color-magnitude diagram (CMD) of the Milky Way globular cluster M30. Their presence has been suggested to be related to the two BSS formation channels (namely, collisions and mass transfer in close binaries) operating within the same stellar system. The blue sequence was indeed found to be well reproduced by collisional BSS models. In contrast, no specific models for mass-transfer BSSs were available for an old stellar system like M30. Here we present binary evolution models, including case-B mass transfer and binary merging, specifically calculated for this cluster. We discuss in detail the evolutionary track of a 0.9+0.5M_{sun}_ binary, which spends approximately 4Gyr in the BSS region of the CMD of a 13Gyr old cluster. We also run Monte Carlo simulations to study the distribution of mass-transfer BSSs in the CMD and to compare it with the observational data. Our results show that (1) the color and magnitude distribution of synthetic mass-transfer BSSs defines a strip in the CMD that nicely matches the observed red-BSS sequence, thus providing strong support to the mass-transfer origin for these stars; (2) the CMD distribution of synthetic BSSs never attains the observed location of the blue-BSS sequence, thus reinforcing the hypothesis that the latter formed through a different channel (likely collisions); (3) most (~60%) of the synthetic BSSs are produced by mass-transfer models, while the remaining <40% requires the contribution from merger models.2015ApJ...801...67Xhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/801/67CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/ApJ/772/148 : Blue straggler and red giant stars in M30 (Lovisi+, 2013)J/ApJ/748/91 : Blue straggler stars in M75 (Contreras+, 2012)J/ApJ/681/311 : Blue stragglers in NGC 2419 (Dalessandro+, 2008)J/ApJ/677/1069 : Blue stragglers in NGC 6388 (Dalessandro+, 2008)J/A+A/483/183 : Catalogue of Blue Stragglers (Moretti+, 2008)J/A+A/455/247 : Grid of binaries experiencing mass exchange (Tian+, 2006)J/MNRAS/319/215 : Binary evolution (Han+, 2000)J/ApJ/522/983 : M80 blue straggler stars (Ferraro+, 1999)J/MNRAS/298/525 : Stellar evolution models for Z = 0.0001 to 0.03 (Pols+ 1998)J/AJ/116/1757 : M30 UBV photometry (Guhathakurta+, 1998)J/A+A/324/915 : Blue stragglers in M3 (Ferraro+ 1997)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/801/67https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/801/67http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/801/67https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/801/67https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/801/67http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/801/67GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapdefaultJ/ApJ/801/67/table2Grid of binary modelsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintAge[13] Current ageGyrtime.agefloatM1g[0.7/1] Initial mass of primarysolMassphys.massfloatM2g[0.3/0.8] Initial mass of secondarysolMassphys.massfloatag[1.6/7.3] Initial orbital separation of binarysolRadpos.angDistance;src.orbitalfloatF555W[0.6/5.3] HST/WFPC2 F555W band magnitudes at 13Gyrmagphot.mag;em.opt.VfloatV-I[-0.05/1] The (F555W-F814W) color index at 13Gyrmagphot.color;em.opt.V;em.opt.Ifloat