J/AJ/156/179ivo://CDS.VizieR/J/AJ/156/179doi:10.26093/cds/vizier.51560179CDSRoederer I.U.Hattori K.Valluri M.2019-05-06T14:38:39Z2019-04-02T06:38:18ZCDS support team

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

cds-question@unistra.frmilky-way-galaxychemically-peculiar-starschemical-abundancesvisible-astronomytrigonometric-parallaxproper-motionsstellar-distanceradial-velocitystellar-radiiWe present the kinematics of 35 highly r-process-enhanced ([Eu/Fe]>=+0.7) metal-poor (-3.8<[Fe/H]< -1.4) field stars. We calculate six-dimensional positions and velocities, evaluate energies and integrals of motion, and compute orbits for each of these stars using parallaxes and proper motions from the second Gaia data release (Cat. I/345) and published radial velocities. All of these stars have halo kinematics. Most stars (66%) remain in the inner regions of the halo (<13 kpc), and many (51%) have orbits that pass within 2.6 kpc of the Galactic center. Several stars (20%) have orbits that extend beyond 20 kpc, including one with an orbital apocenter larger than the Milky Way virial radius. We apply three clustering methods to search for structure in phase space, and we identify eight groups. No abundances are considered in the clustering process, but the [Fe/H] dispersions of the groups are smaller than would be expected by random chance. The orbital properties, clustering in phase space and metallicity, and the lack of highly r-process-enhanced stars on disk-like orbits, indicate that such stars likely were accreted from disrupted satellites. Comparison with the galaxy luminosity-metallicity relation suggests M_V_>~-9 for most of the progenitor satellites, characteristic of ultra-faint or low-luminosity classical dwarf spheroidal galaxies. Environments with low rates of star formation and Fe production, rather than the nature of the r-process site, may be key to obtaining the [Eu/Fe] ratios found in highly r-process-enhanced stars.2018AJ....156..179Rhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/156/179CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toI/345 : Gaia DR2 (Gaia Collaboration, 2018)I/347 : Distances to 1.33 billion stars in Gaia DR2 (Bailer-Jones+, 2018)J/AJ/119/2866 : Proper motions of metal-poor stars (Beers+, 2000)J/ApJ/681/1524 : Detailed abundances for 28 metal-poor stars (Lai+, 2008)J/AJ/137/272 : Space velocities orbits in the Milky Way haloJ/MNRAS/418/284 : s-process in low-metallicity stars. II. (Bisterzo+, 2011)J/ApJ/794/58 : Metal-poor stars in the thick disk of the GalaxyJ/A+A/586/A49 : r- and s- process elements in Milky Way diskhttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/156/179https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/156/179http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/156/179https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/156/179https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/156/179http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/156/179GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/AJ/156/179/table1 (List of known highly r-process-enhanced field stars, sorted by decreasing [Eu/Fe] ratios)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/156/179/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/156/179/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/156/179/table1?GETtext/xml+votable180.050000true359.3287778-0.87984360.0055555555555555566/51 5886 8266 10476 16462 16503 16569 16582 17406 17420 17642 18452 18587 19070 19209 20390 22635 23304 25413 25482 25959 26242 26994 28740 28744 28938 30031 30858 32352 32949 33019 33249 33470 33696 34019 34254 34995 35649 36642 36788 36806 38868 38919 38957 41244 42076 42308 42323 43367 44304 44331 44445 44890 45309 45397 45679 45804 45818 46090 46098 46155 46156 46490 46493 46580 46659 46722 46851 46902 47169 47201 47331 47353 47458 47608 47672 47776 47802 47854 47855 48501 48926 49001https://cdsarc.cds.unistra.fr/viz-bin/moc/J/AJ/156/179?format=asciiOpticaldefaultJ/AJ/156/179/table1List of known highly r-process-enhanced field stars, sorted by decreasing [Eu/Fe] ratiosSimbadNameSimbad column added by the CDSmeta.idcharmoreindicates data in Tables 2-5 for this starmeta.ref.urlcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintStarStar namemeta.id;meta.maincharprimary[Fe/H][-3.71/-1.47] Metallicityphys.abund.Zfloat[Eu/Fe][0.7/1.92] Europium-to-iron ratiophys.abundfloat[Eu/H][-2.71/-0.14] Europium-to-hydrogen ratiophys.abundfloatRefReferencemeta.ref;pos.framecharBibcodeBibcode of the referencemeta.bib.bibcodechar_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/AJ/156/179/table3Calculated velocities in a cylindrical coordinate systemStarStar namemeta.id;meta.maincharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintVR[-274.9/246.9] Calculated median velocity in a cylindrical coordinate system V_R_ (1)km/sphys.veloc;pos.galactocentricfloatVR16[0.4/67.4] 16th percentile V_R_ confidence intervalkm/sstat.errorfloatVR84[0.4/125] 84th percentile V_R_ confidence intervalkm/sstat.errorfloatVPhi[-262.2/336.1] Calculated median velocity in a cylindrical coordinate system V_{Phi}_ (2)km/sphys.velocfloatVPhi16[0.5/87] 16th percentile V_{Phi}_ confidence intervalkm/sstat.errorfloatVPhi84[0.4/55.3] 84th percentile V_{Phi}_ confidence intervalkm/sstat.errorfloatVz[-230.3/271.5] Calculated median velocity in a cylindrical coordinate system V_z_ (3)km/sphys.veloc;pos.cartesian.zfloatVz16[0.3/28.8] 16th percentile V_z_ confidence intervalkm/sstat.errorfloatVz84[0.3/45.4] 84th percentile V_z_ confidence intervalkm/sstat.errorfloatVperp[18.1/338.3] Tangential velocity V{perp} (4)km/sphys.veloc.transversefloatVperp16[0.2/35.7] 16th percentile V{perp} confidence intervalkm/sstat.errorfloatVperp84[0.2/85.4] 84th percentile V{perp} confidence intervalkm/sstat.errorfloatJ/AJ/156/179/table4Calculated orbital energies and angular momentarecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintStarStar namemeta.id;meta.maincharE[-132/-13.4] Orbital energy1000km**2.s**-2src.orbitalfloatE16[0.1/17.4] 16th percentile E confidence interval1000km**2.s**-2stat.errorfloatE84[0.1/37] 84th percentile E confidence interval1000km**2.s**-2stat.errorfloatJr[21.3/24200] Calculated median radial action J_r_kpc.km/sarith.grad;phys.velocfloatJr16[1.7/7770] 16th percentile J_r_ confidence intervalkpc.km/sstat.errorfloatJr84[2/31300] 84th percentile J_r_ confidence intervalkpc.km/sstat.errorfloatJPhi[-2360/2670] Calculated median azimuthal action J_{Phi}_kpc.km/sphys.angMomentumfloatJPhi16[3.5/745] 16th percentile J_{Phi}_ confidence intervalkpc.km/sstat.errorfloatJPhi84[3.2/605] 84th percentile J_{Phi}_ confidence intervalkpc.km/sstat.errorfloatJz[6.1/1080] Calculated median vertical action J_z_kpc.km/sarith.grad;phys.velocfloatJz16[0.1/164] 16th percentile J_z_ confidence intervalkpc.km/sstat.errorfloatJz84[0.1/407] 84th percentile J_z_ confidence intervalkpc.km/sstat.errorfloatJ/AJ/156/179/table5Calculated orbital parametersStarStar namemeta.id;meta.maincharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintrperi[0.13/8.67] Calculated median pericentric radius r_peri_kpcphys.size.radius;stat.medianfloatrperi16[0.01/1.41] 16th percentile r_peri_ confidence intervalkpcstat.errorfloatrperi84[0.02/1.31] 84th percentile r_peri_ confidence intervalkpcstat.errorfloatrapo[6.05/434] Calculated median apocentric radius r_apo_kpcphys.size.radius;stat.medianfloatrapo16[0/138] 16th percentile r_apo_ confidence intervalkpcstat.errorfloatrapo84[0/140] 84th percentile r_apo_ confidence intervalkpcstat.errorfloatZmax[0.69/151] Calculated median maximum distance above or below the Galactic plane Z_max_kpcpos.distance;em.wl.central;stat.medianfloatZmax16[0.01/53] 16th percentile Z_max_ confidence intervalkpcstat.errorfloatZmax84[0.01/60.9] 84th percentile Z_max_ confidence intervalkpcstat.errorfloate[0.173/0.975] Eccentricitysrc.orbital.eccentricityfloate16[0.003/0.168] 16th percentile e confidence intervalstat.errorfloate84[0.002/0.213] 84th percentile e confidence intervalstat.errorfloatJ/AJ/156/179/table2Parallaxes, proper motions, distances, and radial velocitiesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintStarStar namemeta.id;meta.maincharGaiaGaia DR2 (Cat. I/345) source identifiermeta.idPlx[0.1779/6.7911] Gaia DR2 parallaxmaspos.parallaxfloate_Plx[0.0141/0.0587] 1{sigma} uncertainty in Plxmasstat.error;pos.parallaxfloatpmRA[-228.893/211.493] Gaia DR2 proper motion along RA (pmRA*cosDE)mas/yrpos.pm;pos.eq.radoublee_pmRA[0.026/0.095] Uncertainty in pmRAmas/yrstat.error;pos.pm;pos.eq.rafloatpmDE[-212.06/9.317] Gaia DR2 proper motion along DEmas/yrpos.pm;pos.eq.decdoublee_pmDE[0.022/0.067] 1{sigma} uncertainty in pmDEmas/yrstat.error;pos.pm;pos.eq.decfloatDist[0.147/4.595] Distance adopted from Bailer-Jones et al. (2018, Cat. I/347) and based on Gaia DR2 parallaxkpcpos.distance;pos.heliocentricfloatDist16[0.001/0.381] 16th percentile distance confidence intervalkpcstat.errorfloatDist84[0.001/0.453] 84th percentile distance confidence intervalkpcstat.errorfloatHRV[-377.1/372.8] Heliocentric radial velocitykm/sspect.dopplerVeloc;pos.heliocentricfloate_HRV[0.1/3] 1{sigma} uncertainty in HRVkm/sstat.errorfloatr_HRVReference(s) for HRVmeta.ref;pos.framecharn_r_HRV[a] Note on HRV reference (1)meta.notecharBibcodeBibcode of the reference(s)meta.bib.bibcodechar