J/A+A/711/A288ivo://CDS.VizieR/J/A+A/711/A288CDSOlivares Carvajal J.Rojas-Arriagada A.Zoccali M.Acosta-Tripailao B.,De Leo M.Albarracin R.Sanchez-Benavente M.Valenti E.Bono G.,Duffau S.Sbordone L.Fabrizio M.Braga V.F.2026-07-22T06:50:59Z2026-07-22T07:45:47ZCDS support team

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

cds-question@unistra.frmilky-way-galaxyvariable-starsmetallicitychemical-abundancesradial-velocityproper-motionsstellar-distancevisible-astronomyThe shape and kinematics of the metal-poor stellar component of the Galactic bulge remain poorly characterized, so its origin is still weakly constrained. RR Lyrae (RRL) stars trace this old, relatively metal-poor component and, thanks to precise distances, allow orbits to be computed while minimizing contamination. So far no medium/high-resolution spectroscopic study had targeted bulge RRL. We present a spectroscopic determination of iron and alpha-element abundances for RRL stars in two fields of Baade's Window, a low-extinction bulge window, with the goal of providing a benchmark to calibrate photometric metallicity indicators for this population. We analysed FLAMES/GIRAFFE HR10 spectra of 78 RRL (60 ab-type and 18 c-type) using a full-spectrum fitting technique (FERRE) to derive the spectroscopic metallicity and the overall alpha-element abundance. Distances were obtained from a period-luminosity-metallicity relation, and orbits were computed by combining the radial velocities derived here with Gaia DR3 proper motions. The metallicity distributions peak at [Fe/H]_median_=-1.34+/-0.04 and -1.44+/-0.08dex for ab- and c-type stars, respectively, with relatively high alpha-element abundances around [a/Fe] ~ 0.25 dex. The spectroscopic values are used to test several photometric metallicity methods, which show systematic offsets. A few ab-type RRL with [Fe/H]>-1 dex and low [a/Fe] show disk-like kinematics, suggesting a possible second, slightly younger RRL population in the bulge region.2026A&A...711A.288Ohttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/711/A288CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/A+A/687/A312 : Bulge RR Lyrae 3D kinematics (Olivares Carvajal+, 2024)J/AcA/69/321 : OGLE-IV RR Lyrae in bulge & disk (Soszynski+, 2019)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/711/A288https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/711/A288http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/711/A288https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/711/A288https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/711/A288http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/711/A288GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/711/A288/table1 (Observational parameters and abundances)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/711/A288/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/711/A288/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/711/A288/table1?GETtext/xml+votable180.050000true270.98004111-28.656083060.0055555555555555566/28778-28779 288652.367228618189496e-19 2.6706780932288093e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/711/A288?format=asciiOpticaldefaultJ/A+A/711/A288/table1Observational parameters and abundancesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintOGLEOGLE-BLG-RRLYR identifier (G1)meta.id;meta.mainintTypeRR Lyrae pulsation type (1)meta.notecharRAJ2000Right ascension (J2000)degpos.eq.ra;meta.mainDEJ2000Declination (J2000)degpos.eq.dec;meta.mainPPulsation period (OGLE-IV)dtime.perioddoubleImagI-band mean magnitude (OGLE-IV)magphot.mag;em.opt.IfloatAmpII-band amplitude (OGLE-IV)magsrc.var.amplitudefloat[Fe/H]Spectroscopic iron abundancephys.abund.Fefloate_[Fe/H]Error on [Fe/H]stat.error;phys.abund.Fefloat[a/Fe]Spectroscopic alpha-element abundancephys.abundfloate_[a/Fe]Error on [a/Fe]stat.error;phys.abundfloatDist? Heliocentric distancekpcpos.distancefloatnullableVsyst? Systemic radial velocitykm/sphys.veloc;pos.heliocentricdoublenullablepmRA? Gaia DR3 pmRA*cosDE (2)mas/yrpos.pm;pos.eq.rafloatnullableSimbadSimbad column added by the CDSmeta.ref.urlcharpmDE? Gaia DR3 pmDE (2)mas/yrpos.pm;pos.eq.decfloatnullableGaiaDR3Gaia DR3 source identifiermeta.idJ/A+A/711/A288/table2Orbital parameters derived for the RRLsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintOGLEOGLE-BLG-RRLYR identifier (G1)meta.id;meta.mainintClassStellar group (1)src.classchar[Fe/H]Spectroscopic iron abundancephys.abund.Fefloate_[Fe/H]Error on [Fe/H]stat.error;phys.abund.Fefloat[a/Fe]Spectroscopic alpha-element abundancephys.abundfloate_[a/Fe]Error on [a/Fe]stat.error;phys.abundfloatEtotTotal orbital energykm**2.s**-2phys.energydoubleLzVertical angular momentumkpc.km/sphys.angMomentumdoubleJparNormalised parallel actionphys.angMomentumdoubleJperpNormalised perpendicular actionphys.angMomentumdoublecircOrbit circularitystat.fit.paramdoubleApoApocentre radiuskpcphys.size.radiusfloate_ApoError on Apokpcstat.errorfloatPeriPericentre radiuskpcphys.size.radiusfloate_PeriError on Perikpcstat.errorfloatZmaxMaximum height above the planekpcpos.cartesian.z;stat.maxfloatEccOrbit eccentricitysrc.orbital.eccentricityfloate_EccError on Eccstat.errorfloat