J/AJ/108/1016ivo://CDS.VizieR/J/AJ/108/1016doi:10.26093/cds/vizier.51081016CDSLayden A.C.2023-04-06T16:50:07Z1999-02-27T12:47:23ZCDS support team

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

cds-question@unistra.frvariable-starsphotometrymetallicityradial-velocityIn order to study the structure and formation history of the galaxy, we have obtained low-to-moderate dispersion spectra of 302 nearby RR Lyrae variables of Bailey type "ab". We derived abundances, typically accurate to 0.15-0.20dex and calibrated to the Zinn & West (1984ApJS...55...45Z) globular cluster metallicity scale, from the pseudo-equivalent widths of the Ca II K, Hdelta, Hgamma, and Hbeta lines. Radial velocities accurate to between 2 and 30km/s were obtained from the spectra and from the literature. Distances accurate to between 5% and 20% were derived from published apparent magnitudes and Burstein & Heiles (1982AJ.....87.1165B) reddenings. The metallicity distribution of the RR Lyrae stars peaks at [Fe/H]_K_ =~ -1.5, and is narrower than that of the Ryan & Norris (1991AJ....101.1865R) subdwarfs, as expected since the most metal-rich and metal-poor progenitors preferentially appear as stable red and blue horizontal branch stars, rather than as RR Lyrae. The metal-rich tail of the RR Lyrae distribution extends to [Fe/H]_K_{approx}0, and a qualitative analysis of the distribution of distances from the galactic plane shows that the stars in this tail (i.e., [Fe/H]_K_>-1.0) are more concentrated to the plane than the more metal-poor stars. The abundance distribution of the local RR Lyrae stars is in excellent agreement with the changing abundance distributions of distant RR Lyrae stars as a function of galactocentric distance, as derived by Suntzeff et al. (1991ApJ...367..528S), who ascribed this change to systematic variations in horizontal branch morphology (probably age variations) with galactocentric distance. The abundance distribution of the local RR Lyrae stars also agrees well with those of the distant RR Lyrae stars as a function of distance from the galactic plane. There is no evidence for an abundance gradient in this direction, suggesting that gaseous dissipation did not play a major role in the formation of the outer halo. Addresses: Layden A.C. <alayden@noao.edu> Department of Astronomy, Yale University, P.O. Box 208101 New Haven, Connecticut 06520-81011994AJ....108.1016Lhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/108/1016CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/AJ/110/2288 : Kinematics of local RR Lyrae. II. (Layden 1995)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/108/1016https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/108/1016http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/108/1016https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/108/1016https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/108/1016http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/108/1016GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/AJ/108/1016/table9New data for local RR Lyrae variablesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameVariable star name (as in GCVS4, <II/139>)meta.id;meta.mainchar[Fe/H]Metal abundance, on Zinn & West (1984ApJS...55...45Z) scalelog(Sun)phys.abund.Fefloatu_[Fe/H]Uncertainty flag on [Fe/H]meta.code.errorchare_[Fe/H]rms uncertainty on [Fe/H]log(Sun)stat.errorfloato_[Fe/H]Number of spectra used for [Fe/H] estimatemeta.numberint<V>Intensity-averaged V magnitude (see n_<V>)magphot.mag;em.opt.Vfloatr_<V>Reference for <V> (see n_<V>) (1)meta.refcharn_<V>Photometric passband (2)meta.notecharAVInterstellar absorption in V (3)phys.absorptionfloatDistDistance from Sunkpcpos.distancefloate_Distrms uncertainty on distancekpcstat.errorfloatZDistance from Galactic planekpcpos.galacticfloatRgcDistance from Galactic center, assumes Ro=8kpckpcpos.distancefloatRVSystemic radial velocitykm/sphys.velocinte_RVEstimated error in measured radial velocitykm/sstat.errorinto_RVNumber of spectra used in Vrad estimatemeta.numberintMethodRadial velocity combination method (4)meta.noteintVsysFinal systemic radial velocity (5)km/sphys.veloc;pos.heliocentricinte_VsysEstimated error in Vsyskm/sstat.errorintu_Vsys':' indicates disagreement in velocity (6)meta.code.errorchar