J/ApJ/858/92ivo://CDS.VizieR/J/ApJ/858/92doi:10.26093/cds/vizier.18580092CDSHansen T.T.Holmbeck E.M.Beers T.C.Placco V.M.Roederer I.U.,Frebel A.Sakari C.M.Simon J.D.Thompson I.B.2019-03-29T15:38:54Z2018-06-12T10:43:05ZCDS support team

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

cds-question@unistra.frpopulation-ii-starschemically-peculiar-starschemical-abundancesline-intensitiesThe recent detection of a binary neutron star merger and the clear evidence for the decay of radioactive material observed in this event have, after 60 years of effort, provided an astrophysical site for the rapid neutron- capture (r-) process which is responsible for the production of the heaviest elements in our universe. However, observations of metal-poor stars with highly-enhanced r-process elements have revealed abundance patterns suggesting that multiple sites may be involved. To address this issue and to advance our understanding of the r-process, we have initiated an extensive search for bright (V<13.5), very metal-poor ([Fe/H]<-2) stars in the Milky Way halo exhibiting strongly-enhanced r-process signatures. This paper presents the first sample collected in the southern hemisphere using the echelle spectrograph on du Pont 2.5m telescope at Las Campanas Observatory. We have observed and analyzed 107 stars with -3.13<[Fe/H]<-0.79. Of those, 12 stars are strongly enhanced in heavy r-process elements (r-II), 42 stars show moderate enhancements of heavy r-process material (r-I), and 20 stars exhibit low abundances of the heavy r-process elements and higher abundances of the light r-process elements relative to the heavy ones (limited-r). This search is more successful at finding r- process-enhanced stars compared to previous searches, primarily due to a refined target-selection procedure.2018ApJ...858...92Hhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/858/92CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toII/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)II/294 : The SDSS Photometric Catalog, Release 7 (Adelman-McCarthy+, 2009)I/322 : UCAC4 Catalogue (Zacharias+, 2012)III/279 : RAVE 5th data release (Kunder+, 2017)J/AJ/90/2089 : Stars of very low metal abundance. I (Beers+, 1985)J/AJ/103/1987 : Stars of very low metal abundance (Beers+ 1992)J/ApJ/617/1091 : La and Eu abundances in 85 stars (Simmerer+, 2004)J/A+A/439/129 : HERES II. Spectroscopic analysis (Barklem+, 2005)J/AJ/130/2804 : Carbon abundances in metal-poor stars (Rossi+, 2005)J/ApJ/652/1585 : Bright metal-poor stars from HES survey (Frebel+, 2006)J/ApJS/168/128 : UBVRcIc photometry of FHB and metal-poor stars (Beers+, 2007)J/A+A/484/721 : HES survey. IV. Candidate metal-poor stars (Christlieb+, 2008)J/ApJ/681/1524 : Detailed abundances for 28 metal-poor stars (Lai+, 2008)J/ApJ/701/1053 : Abundances of 8 stars in the Draco dSph (Cohen+, 2009)J/AJ/137/4377 : List of SEGUE plate pairs (Yanny+, 2009)J/ApJ/719/931 : Chemical evolution of the UMi dSph (Cohen+, 2010)J/A+A/523/A17 : Individual stars in Fornax dSph center (Letarte+, 2010)J/AJ/141/175 : Abundances in M15 RGB/RHB stars (Sobeck+, 2011)J/ApJ/778/56 : Hamburg/ESO Survey extremely metal-poor stars (Cohen+, 2013)J/ApJ/769/57 : Equivalent widths of metal-poor stars (Frebel+, 2013)J/ApJ/775/L27 : Chemical abundances in a metal-poor RGB star (Johnson+, 2013)J/ApJ/794/58 : Metal-poor stars in the Galaxy thick disk (Beers+, 2014)J/A+A/569/A43 : HE 2252-4225 abundance analysis (Mashonkina+, 2014)J/A+A/571/A47 : Extensive CH linelist in stellar atmospheres (Masseron+, 2014)J/AJ/148/81 : APASS BVgri photometry of RAVE stars. I. Data (Munari+, 2014)J/ApJS/211/5 : Improved line data for the Swan system ^12^C^13^C (Ram+, 2014)J/AJ/147/136 : Stars of very low metal abundance. VI. (Roederer+, 2014)J/ApJ/797/13 : Abundances of bright metal-poor stars (Schlaufman+, 2014)J/ApJS/214/26 : Line lists for CN isotopes transitions (Sneden+, 2014)J/ApJ/807/171 : SkyMapper Survey metal-poor star spectrosc. (Jacobson+, 2015)J/ApJ/830/93 : Abundances of Ret II brightest red giant members (Ji+, 2016)J/AJ/151/82 : 4 brightest red giants in Ret 2 (Roederer+, 2016)J/ApJ/835/81 : Bright metal-poor stars from HES Survey. II. (Beers+, 2017)J/ApJ/847/142 : Ultra-metal-poor stars LTE & NLTE abund. (Ezzeddine+, 2017)J/ApJ/838/44 : Abundances of the brightest member of Tuc III (Hansen+, 2017)J/ApJ/844/18 : RAVE J203843.2-002333 spectroscopy (Placco+, 2017)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/858/92https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/858/92http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/858/92https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/858/92https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/858/92http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/858/92GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/858/92/stars (Stellar parameters and abundances (tables 4 and 5))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/858/92/stars?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/858/92/stars?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/858/92/stars?GETtext/xml+votable180.050000true0.094125-13.04097220.005555555555555556Cone search capability for table J/ApJ/858/92/table2 (Observation log for the 107 stars)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/858/92/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/858/92/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/858/92/table2?GETtext/xml+votable180.050000true0.094167-13.0409720.0055555555555555566/16602 16627 16828 17027 17032 17122 17181 17203 17420 18762 18784 18964 18968 19061 19083 22662 29978 30036 30858 30874 30893 30944 31642 32949 33261 33286 33363 33473 33695 33738 34918 34935 34995 35112 35390 35649 35665 35704 35782 35913 36465 36642 36650 41223 41244 41307 41335 42009 42022 42076 42100 42104 42250 42892 43367 43503 43957 44206 44331 44500 44570 44573 44620 44890 45309 45408 45583 45612 45717 45718 45743 45804 45807 45808 45838 45877 45984 46017 46023 46026 46156 46215 46394 46483 46722 46744 47169 47190 47201 47331 47353 47608 47649 47672 47699 47776 47851 48289 48518 48660 48674 48708 48916 48926 48946 48982 49001https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/858/92?format=asciidefaultJ/ApJ/858/92/starsStellar parameters and abundances (tables 4 and 5)[Eu/Fe][-0.4/2.1] log Eu/Fe number abundance ratiolog(Sun)phys.abundfloatl_[Ba/Eu]Limit flag on [C/Fe]meta.code.errorcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordint2MASSStellar identifier (JHHMMSSss+DDMMSSs)meta.id;meta.maincharprimaryTeff[4250/6311] Effective temperatureKphys.temperature.effectiveintlog(g)[0.1/4.6] log surface gravitylog(cm.s**-2)phys.gravityfloat[Fe/H][-3.2/-0.7] Metallicitylog(Sun)phys.abund.Zfloate_[Fe/H][0.09/0.3] Uncertainty in [Fe/H]log(Sun)stat.error;phys.abund.FefloatN(FeI)[28/140] Number of Fe I lines usedmeta.numberintN(FeII)[6/27] Number of Fe II lines usedmeta.numberintVt[0.7/3] Microturbulent velocitykm/sphys.velocfloatNobsNumber of observations for this star (link to Table 2)meta.numberintnullableEWDisplay the equivalent widths for this starmeta.ref.urlchar[Fe/H]n[-3.2/-0.7] log Fe/H number abundance ratiolog(Sun)phys.abundfloatl_[C/Fe]Limit flag on [C/Fe]meta.code.error;phys.abundchar[C/Fe][-1.2/2] log C/Fe number abundance ratiolog(Sun)phys.abundfloatl_[Sr/Fe]Limit flag on [C/Fe]meta.code.error;phys.abundchar[Sr/Fe][-2.5/2] log Sr/Fe number abundance ratiolog(Sun)phys.abundfloatl_[Ba/Fe]Limit flag on [C/Fe]meta.code.error;phys.abundchar[Ba/Fe][-1.7/2.3] log Ba/Fe number abundance ratiolog(Sun)phys.abundfloatl_[Eu/Fe]Limit flag on [C/Fe]meta.code.error;phys.abundchar[Ba/Eu][-2.2/1]? log Ba/Eu number abundance ratiolog(Sun)phys.abundfloatnullablel_[Sr/Ba]Limit flag on [C/Fe]meta.code.errorchar[Sr/Ba][-1.7/1.3] log Sr/Ba number abundance ratiolog(Sun)phys.abundfloatsClassSub classification (1)src.classcharSimbadSimbad column added by the CDSphys.abundchar_RAPositions from 2MASS names (right ascension part)degpos.eq.ra;meta.main_DEPositions from 2MASS names (declination part)degpos.eq.dec;meta.mainJ/ApJ/858/92/table2Observation log for the 107 starsOIDOther identifiermeta.idcharr_VmagSource of Vmag (1)meta.ref;pos.framecharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordint2MASSStellar identifier (JHHMMSSss+DDMMSSs) (G1)meta.id;meta.maincharRAJ2000[0/23] Hour of Right Ascension (J2000)pos.eq.ra;meta.mainDEJ2000[0/75] Degree of Declination (J2000)pos.eq.dec;meta.mainVmag[9/13.6] Apparent V band magnitudemagphot.mag;em.opt.VfloatMJD[57605.4/57611] Modified Julian Datedtime.epochdoubleExp[296/4200] Exposure timestime.duration;obs.exposureintS/N[17/80] Signal-to-Noise at 4129Astat.snrintRVel[-278.1/432.2] Heliocentric radial velocitykm/sspect.dopplerVeloc;pos.heliocentricfloate_RVel[0.08/2.2] Uncertainty in RVelkm/sstat.error;spect.dopplerVelocfloatJ/ApJ/858/92/ew_allFe I and Fe II equivalent width measurements (Table 3 of the paper)IonAtomic species (Fe I or Fe II)phys.atmol.ionStagecharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordint2MASS2MASS identifier (JHHMMSSss+DDMMSSs) (G1)meta.id;meta.maincharlambda[3878/8689] Transition wavelength (in Angstrom units)0.1nmem.wl;phys.atmol.transitionfloatEP[0/5] Excitation potentialeVphys.atmol.excitationfloatloggf[-6/0.7] Log of oscillator strengthphys.atmol.oscStrengthfloatEW[1.4/217.5] Measured equivalent width (in milli-Angstrom units)1e-13mspect.line.eqWidthfloatA[3.7/7.1] Derived abundance (loge)log(Sun)phys.abundfloat