J/ApJ/914/10ivo://CDS.VizieR/J/ApJ/914/10doi:10.26093/cds/vizier.19140010CDSCrestani J.Braga V.F.Fabrizio M.Bono G.Sneden C.Preston G.,Ferraro I.Iannicola G.Nonino M.Fiorentino G.Thevenin F.Lemasle B.,Prudil Z.Alves-Brito A.Altavilla G.Chaboyer B.Dall'Ora M.,D'Orazi V.Gilligan C.Grebel E.K.Koch-Hansen A.J.Lala H.Marengo M.,Marinoni S.Marrese P.M.Martinez-Vazquez C.Matsunaga N.Monelli M.,Mullen J.P.Neeley J.da Silva R.Stetson P.B.Salaris M.Storm J.,Valenti E.Zoccali M.2025-02-13T20:11:22Z2022-12-23T10:10:24ZCDS support team

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

cds-question@unistra.frchemical-abundancesvariable-starsvisible-astronomyspectroscopyWe provide the largest and most homogeneous sample of {alpha}-element (Mg, Ca, Ti) and iron abundances for field RR Lyrae (RRLs; 162 variables) by using high-resolution spectra. The current measurements were complemented with similar abundances available in the literature for 46 field RRLs brought to our metallicity scale. We ended up with a sample of old (t>=10Gyr), low-mass stellar tracers (208 RRLs: 169 fundamental, 38 first overtone, and 1 mixed mode) covering 3dex in iron abundance (-3.00<=[Fe/H]<=0.24). We found that field RRLs are ~0.3dex more {alpha} poor than typical halo tracers in the metal-rich regime ([Fe/H]>=-1.2), while in the metal-poor regime ([Fe/H]<=-2.2) they seem to be on average ~0.1dex more {alpha} enhanced. This is the first time that the depletion in {alpha} elements for solar iron abundances is detected on the basis of a large, homogeneous, and coeval sample of old stellar tracers. Interestingly, we also detected a close similarity in the [{alpha}/Fe] trend between {alpha}-poor, metal-rich RRLs and red giants (RGs) in the Sagittarius dwarf galaxy as well as between {alpha}-enhanced, metal-poor RRLs and RGs in ultrafaint dwarf galaxies. These results are supported by similar elemental abundances for 46 field horizontal branch stars. These stars share with RRLs the same evolutionary phase and the same progenitors. This evidence further supports the key role that old stellar tracers play in constraining the early chemical enrichment of the halo and, in particular, in investigating the impact that dwarf galaxies have had in the mass assembly of the Galaxy.2021ApJ...914...10Chttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/914/10CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toVII/195 : Globular Clusters in the Milky Way (Harris, 1996)VII/202 : Globular Clusters in the Milky Way (Harris, 1997)J/AJ/110/2319 : Abundances in RR Lyr variables (Clementini+ 1995)J/MNRAS/340/304 : [X/Fe] of Galactic disc F and G dwarfs (Reddy+, 2003)J/A+A/416/1117 : Abundances in the early Galaxy (Cayrel+, 2004)J/AJ/128/1177 : Galactic stellar abundances (Venn+, 2004)J/AJ/130/2140 : Abundances & velocities in globular clusters (Pritzl+, 2005)J/MNRAS/367/1329 : Elemental abundances for 176 stars (Reddy+, 2006)J/A+A/465/815 : Abundances of Sgr dSph stars (Sbordone+, 2007)J/AJ/135/1580 : Abundances in 10 red giants of Car dSph (Koch+, 2008)J/A+A/505/139 : Abundances of red giants in 17 GCs (Carretta+, 2009)J/A+A/505/117 : Abundances of red giants in 15 GCs (Carretta+, 2009)J/ApJ/701/1053 : Abundances of 8 stars in the Draco dSph (Cohen+, 2009)J/ApJ/712/L21 : Calcium abundances in 17 globular clusters (Carretta+, 2010)J/A+A/520/A95 : Abundances of red giants in M54 & Sgr dSph (Carretta+, 2010)J/AJ/140/1694 : Abundances of non-variable red & blue HB stars (For+, 2010)J/AN/331/474 : Abundances of metal-poor stars (Frebel, 2010)J/ApJ/708/560 : Spectroscopy of UMa II and Coma Ber (Frebel+, 2010)J/A+A/523/A17 : Individual stars in Fornax dSph center (Letarte+, 2010)J/A+A/511/L10 : Abundances and space velocities of 94 stars (Nissen+, 2010)J/A+A/511/A56 : Abundances of five open clusters (Pancino+, 2010)J/ApJS/197/29 : Chemical compositions of 11 RR Lyrae (For+, 2011)J/A+A/530/A54 : Abundances of 650 bulge red giants (Gonzalez+, 2011)J/ApJ/778/149 : Abundances for 3 stars in Sgr dSph (McWilliam+, 2013)J/ApJ/767/134 : Abundances of red giant stars in UFD gal. (Vargas+, 2013)J/ApJS/208/27 : Sun and HD 84937 TiII log(gf) and abundances (Wood+, 2013)J/A+A/562/A71 : Abundances of solar neighbourhood dwarfs (Bensby+, 2014)J/ApJ/782/59 : Abundances of RR Lyrae subclass C var. stars (Govea+, 2014)J/A+A/572/A82 : Abundances in outer parts of Fornax dSph (Hendricks+, 2014)J/A+A/572/A88 : Equivalent widths for Fornax RGB stars (Lemasle+, 2014)J/A+A/580/A18 : Carina Project VIII. {alpha}-element abund (Fabrizio+, 2015)J/A+A/584/A46 : GIRAFFE Inner Bulge Survey (GIBS). II. (Gonzalez+, 2015)J/MNRAS/447/2404 : Equivalent width of 21 RR Lyrae stars (Pancino+, 2015)J/A+A/587/A124 : Metal-poor stars towards the Galactic bulge (Koch+, 2016)J/ApJ/848/68 : Abund. & RVs of stable and Blazhko RRc stars (Sneden+, 2017)J/AJ/155/240 : A spectroscopic survey of field RHB stars (Afsar+, 2018)J/ApJ/852/49 : Properties of metal-poor stars in APOGEE DR13 (Hayes+, 2018)J/ApJS/237/13 : Yields of 13-120M_{sun}_ massive stars (Limongi+, 2018)J/ApJ/870/2 : CCSN to explosions in spheric symmetry. III. (Curtis+, 2019)J/A+A/623/A116 : Gal. Cepheids & RR Lyrae multiplicity. I. (Kervella+, 2019)J/MNRAS/492/3408 : Galactic disc RR Lyrae stars (Prudil+, 2020)J/A+A/641/A127 : 13 dsph and ultra-faint galaxies analysis (Reichert+, 2020)J/ApJ/908/20 : Field RR Lyrae as gal. probes. II. (Crestani+, 2021)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/914/10https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/914/10http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/914/10https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/914/10https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/914/10http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/914/10GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/914/10/table6 (Final abundances for all the RR Lyrae and "Lit-HB" samples in our metallicity and {alpha}-element abundance scale)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/914/10/table6?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/914/10/table6?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/914/10/table6?GETtext/xml+votable180.050000true47.128686110.44589420.005555555555555556Cone search capability for table J/ApJ/914/10/table2 (Basic information of the entire RR Lyrae sample)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/914/10/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/914/10/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/914/10/table2?GETtext/xml+votable180.050000true47.128977686669810.44551023741920.0055555555555555566/110 382 553 572 1663 2238 2248 2484 4152 4322 4373 4479 4762 5287 7174 7518 8294 8323 8367 8466 8773 8779 9138 9769 10282 10328 10584 10602 10811 10898 11098 11123 11197 11961 12512 12576 12696 12743 13171 14697 14994 15097 15106 15220 15281 16018 16462 16602 16849 16867 16923 16934 17158 17254 17328 17538 17745 17748 17955 18177 18303 18536 18580 18633 19104 19110 19169 19333 19924 20303 21127 21131 21146 21182 21533 21928 22111 22338 23271 23613 24351 24590 24602 24614 24621 24623 24724 24772 24866 24913 25060 25120 25199 25491 25611 25768 25803 25879 25953 26079 26131 26281 26288 26589 26756 26807 26981 27047 27148 27260 27279 27333 27512 27824 28040 28155 28582 28701 28813 29703 30019 30055 30868 30923 31335 31390 31417 31498 31589 31592 31608 31648 31683 31743 31787 32254 32352 32558 32636 32663 33465 33467 33996 34232 34236 34240 34285 34407 34491 34537 34600 34606 34944 35151 35423 35629 35652 35678 35686 35714 35724 35758 35944 36048 36295 36605 36704 37911 37970 38087 38259 38304 38360 38456 38809 38942 39152 39767 40475 40553 40767 40806 40924 40952 40988 40998 41022 41191 41260 41285 41318 42007 42053 42068 42260 42672 43387 43405 43491 43764 44832 44914 44924 44991 45324 45337 45801 45859 45868 45881 45994 46069 46075 46080 46130 46373 46396 46462 46464 46482 46580 46650 46686 46691 46705 46751 46851 47074 47217 47342 47446 47467 47618 47821 47856 47867 48113 48145 48160 48162 48228 48290 48363 48459 48544 48576 48591 48715 48911 48916 49011 49102https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/914/10?format=asciiOpticaldefaultJ/ApJ/914/10/table6Final abundances for all the RR Lyrae and "Lit-HB" samples in our metallicity and {alpha}-element abundance scalerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintGaiaDR2Gaia DR2 identificationmeta.id;meta.mainprimary[Fe/H][-3.16/0.23] Median Solar-scaled iron abundancephys.abund.Fe;stat.medianfloate_[Fe/H][0/0.21] Uncertainty in [Fe/H]stat.error;phys.abund.Fefloat[Mg/Fe][-0.22/0.79]? Median Solar-scaled magnesium abundancephys.abundfloatnullablee_[Mg/Fe][0/0.28]? Uncertainty in [Mg/Fe]stat.error;phys.abundfloatnullable[Ca/Fe][-0.3/0.62]? Median Solar-scaled calcium abundancephys.abundfloatnullablee_[Ca/Fe][0.01/0.28]? Uncertainty in [Ca/Fe]stat.error;phys.abundfloatnullable[Ti/Fe][-0.45/0.71]? Median Solar-scaled titanium abundancephys.abundfloatnullablee_[Ti/Fe][0/0.32]? Uncertainty in [Ti/Fe]stat.error;phys.abundfloatnullable[a/Fe][-0.2/0.71] Median Solar-scaled {alpha}-element abundancephys.abundfloatSimbadSimbad column added by the CDSmeta.ref.urlchare_[a/Fe][0/0.23] Uncertainty in [alpha/Fe]stat.error;phys.abundfloatSampleSample ("Lit-HB", "Lit-RRL" or "TW-RRL"=this work RRL)src.samplecharRefSource (1)meta.bibcharPapIIDisplay data from Paper II (Crestani+ 2021, J/ApJ/908/20)meta.ref.urlintnullableSDisplay the basic information for this RRL (link to Table 2)meta.ref.urlintnullableNabNumber of measurements derived in this work for this RRL (link to Table 4)meta.numberintnullableADisplay the abundances adopted from the literature for this RRL (link to Table 3)meta.ref.urlintnullable_RARight Ascension (J2000) from SIMBAD (not part of the original data)degpos.eq.ra;meta.main_DEDeclination (J2000) from SIMBAD (not part of the original data)degpos.eq.dec;meta.mainJ/ApJ/914/10/table2Basic information of the entire RR Lyrae sampleGaiaDR2Gaia DR2 identificationmeta.id;meta.mainrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintONameOther name for the starmeta.idcharRA_ICRSRight ascension (ICRS) at Epoch=2015.5degpos.eq.ra;meta.mainDE_ICRS[-84.41/69.52] Declination (ICRS) at Epoch=2015.5degpos.eq.dec;meta.mainVmag[7.78/17.24] Mean V-band magnitudemagphot.mag;em.opt.VfloatVamp[0.25/1.31] V-band amplitudemagsrc.var.amplitude;phot.mag;em.opt.VfloatPer[0.2/0.81] Perioddtime.perioddoubleClassPulsation mode ("RRab", "RRc" or "RRd")src.classcharSampleSample ("Lit-RRL" or "TW-RRL"=this work; 162 occurrences)src.samplecharJ/ApJ/914/10/table3RRL abundances adopted from the literatureGaiaDR2Gaia DR2 identificationmeta.id;meta.main[Mg/Fe]o[0.21/0.63]? Solar-scaled magnesium abundance in the literature source (1)phys.abundfloatnullable[Ca/Fe]o[-0.11/0.52]? Solar-scaled calcium abundance in the literature source (1)phys.abundfloatnullable[Ti/Fe]o[0.18/0.8]? Solar-scaled titanium abundance in the literature source (1)phys.abundfloatnullableRefLiterature source (2)meta.bibcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordint[Fe/H]o[-2.9/-0.21] Solar-scaled metallicity in the literature source (1)phys.abund.Fefloat[Fe/H][-2.83/-0.21] Solar-scaled metallicity transformed to our scale (1)phys.abund.Fefloat[Mg/Fe][0/0.6]? Solar-scaled magnesium abundance transformed to our scale (1)phys.abundfloatnullable[Ca/Fe][-0/0.54]? Solar-scaled calcium abundance transformed to our scale (1)phys.abundfloatnullable[Ti/Fe][0.28/0.91]? Solar-scaled titanium abundance transformed to our scale (1)phys.abundfloatnullableJ/ApJ/914/10/table4Atmospheric parameters derived in this work for each individual measurementGaiaDR2Gaia DR2 identificationmeta.id;meta.mainrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintInstSpectrograph identificationmeta.idcharTeff[5750/8220] Effective temperatureKphys.temperature.effectiveinte_Teff[0/940] Uncertainty in TeffKstat.error;phys.temperature.effectiveintlog(g)[0.79/4] Log, Surface gravitylog(cm.s**-2)phys.gravityfloate_log(g)[0.04/0.42] Uncertainty in log (g)log(cm.s**-2)stat.errorfloatVt[1.19/5.82] Microturbulent velocity, {xi}_t_km/sphys.velocfloate_Vt[0.05/2.5] Uncertainty in Vtkm/sstat.errorfloat[FeI/H][-3.11/0.23] Median Solar-scaled iron abundance of neutral iron linesphys.abund.Fe;stat.medianfloate_[FeI/H][0.06/0.28] Uncertainty in [FeI/H]stat.error;phys.abundfloatNFeI[9/234] Number of adopted neutral iron linesmeta.numberint[FeII/H][-3.11/0.23] Median Solar-scaled iron abundance of singly ionized iron linesphys.abund.Fe;stat.medianfloate_[FeII/H][0.01/0.83] Uncertainty [FeII/H]stat.error;phys.abundfloatNFeII[2/39] Number of adopted singly ionized iron linemeta.numberintNstack[1/8] Number of individual spectra stacked for this measurementmeta.numberintJ/ApJ/914/10/table5List of {alpha}-element transitions adopted in this workrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintlambda[3729.81/8717.83] Vacuum wavelength0.1nmem.wlfloatIon[12/22.1] Speciesphys.atmol.ionStagefloatEP[0/5.932] Excitation potentialeVphys.atmol.excitationfloatlog(gf)[-5.62/0.57] log, statistical weight*oscillator strengthstat.weight;phys.atmol.oscStrengthfloatRefLine parameters reference (1)meta.refchar