J/ApJ/946/48ivo://CDS.VizieR/J/ApJ/946/48doi:10.26093/cds/vizier/ba-xj-1gCDSHattori K.Okuno A.Roederer I.U.2026-07-02T11:58:55Z2025-04-09T13:35:31ZCDS support team

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

cds-question@unistra.frchemical-abundanceshalo-starsmilky-way-galaxystellar-associationsvisible-astronomyR-process enhanced stars with [Eu/Fe]>=+0.7 (so-called r-II stars) are believed to have formed in an extremely neutron-rich environment in which a rare astrophysical event (e.g., a neutron-star merger) occurred. This scenario is supported by the existence of an ultra-faint dwarf galaxy, Reticulum II, where most of the stars are highly enhanced in r-process elements. In this scenario, some small fraction of dwarf galaxies around the Milky Way were r enhanced. When each r-enhanced dwarf galaxy accreted to the Milky Way, it deposited many r-II stars in the Galactic halo with similar orbital actions. To search for the remnants of the r-enhanced systems, we analyzed the distribution of the orbital actions of N=161 r-II stars in the solar neighborhood by using Gaia EDR3 data. Since the observational uncertainty is not negligible, we applied a newly developed greedy optimistic clustering method to the orbital actions of our sample stars. We found six clusters of r-II stars that have similar orbits and chemistry, one of which is a new discovery. Given the apparent phase-mixed orbits of the member stars, we interpret that these clusters are good candidates for remnants of completely disrupted r-enhanced dwarf galaxies that merged with the ancient Milky Way.2023ApJ...946...48Hhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/946/48CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toI/345 : Gaia DR2 (Gaia Collaboration, 2018)I/350 : Gaia EDR3 (Gaia Collaboration, 2020)I/355 : Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022)J/ApJ/530/783 : The r-process enriched giant HD 115444 (Westin+, 2000)J/A+A/416/1117 : Abundances in the early Galaxy (Cayrel+, 2004)J/A+A/439/129 : HERES II. Spectroscopic analysis (Barklem+, 2005)J/ApJ/645/613 : Abundances of HD 221170 (Ivans+, 2006)J/ApJ/681/1524 : Detailed abundances for 28 metal-poor stars (Lai+, 2008)J/A+A/516/A46 : HE 2327-5642 abundance analysis (Mashonkina+, 2010)J/ApJ/742/54 : CASH project II. Extremely metal-poor stars (Hollek+, 2011)J/A+A/548/A34 : Abund. of carbon-enhanced metal-poor stars (Allen+, 2012)J/ApJ/753/64 : Abundances for 97 metal-poor stars (Ishigaki+, 2012)J/ApJ/778/56 : Hamburg/ESO Survey extremely metal-poor stars (Cohen+, 2013)J/ApJ/771/67 : Abundances for 97 metal-poor stars. II. (Ishigaki+, 2013)J/ApJ/775/L27 : Abundances in a metal-poor RGB star (Johnson+, 2013)J/ApJ/779/102 : Metallicities of RGB stars in dwarf galaxies (Kirby+, 2013)J/ApJ/767/134 : Abund. of red giant stars in UFD galaxies (Vargas+, 2013)J/A+A/569/A43 : HE 2252-4225 abundance analysis (Mashonkina+, 2014)J/AJ/147/136 : Stars of very low metal abundance. VI. (Roederer+, 2014)J/ApJ/807/171 : SkyMapper Survey metal-poor star sp. (Jacobson+, 2015)J/MNRAS/450/815 : Red giants in NGC 5286 (Marino+, 2015)J/ApJ/808/103 : Kapteyn moving group star abundances (Navarrete+, 2015)J/MNRAS/449/3889 : Abundances of 15 stars in NGC 4833 (Roederer+, 2015)J/ApJ/808/108 : M2FS stellar spectroscopy of Reticulum 2 (Walker+, 2015)J/MNRAS/460/884 : EMBLA survey. Galactic bulge metal-poor stars (Howes+, 2016)J/ApJ/823/157 : LOS velocities & [Fe/H] of Pal 5 (Ishigaki+, 2016)J/AJ/151/82 : The 4 brightest red giants in Ret 2 (Roederer+, 2016)J/A+A/607/A91 : CS 29497-004 abundances (Hill+, 2017)J/ApJ/844/18 : RAVE J203843.2-002333 high-res. spectroscopy (Placco+, 2017)J/ApJ/864/43 : Abund. of 3 bright extremely metal-poor giants (Cain+, 2018)J/ApJ/858/92 : RPA Southern Pilot Search of 107 Stars (Hansen+, 2018)J/AJ/156/179 : r-process-enhanced field stars kinematics (Roederer+, 2018)J/ApJ/865/129 : Abundance analysis of HD 222925 (Roederer+, 2018)J/ApJ/868/110 : R-Process Alliance: 1st release in Gal. halo (Sakari+, 2018)J/MNRAS/485/4726 : An all-sky view of the Orphan Stream (Koposov+, 2019)J/ApJ/874/74 : Local stellar halo member stars from Gaia/LAMOST (Li+, 2019)J/ApJ/874/148 : Metal-poor star RAVE J093730.5-062655 abund. (Sakari+, 2019)J/A+A/627/A173 : Abundances for 4 metal-poor stars (Valentini+, 2019)J/ApJ/898/40 : 2MASSJ15213995-3538094 abundances from sp. (Cain+, 2020)J/ApJ/898/150 : High-res. MIKE obs. of metal-poor stars (Ezzeddine+, 2020)J/A+A/635/A104 : Chemical abundance analysis of HD 20 (Hanke+, 2020)J/A+A/643/A49 : Linelist (Hansen+, 2020)J/ApJS/249/30 : R-Process Alliance: metal-poor star sp. (Holmbeck+, 2020)J/AJ/160/181 : Chemical abundances in red giants with Magellan (Ji+, 2020)J/ApJ/903/88 : Ions individual abund. in LAMOST J1109+0754 (Mardini+, 2020)J/ApJ/905/20 : Metal-poor stars observed with SALT/HRS (Rasmussen+, 2020)J/ApJ/891/39 : LAMOST DR3 very metal-poor stars of Gal. halo (Yuan+, 2020)J/ApJ/908/79 : The r-process Alliance; abund. in 519 stars (Gudin+, 2021)J/ApJ/915/103 : Oscillator strength for Indus_0 & Indus_13 (Hansen+, 2021)J/ApJ/914/123 : Gaia DR2 and EDR3 stars with sp. follow-up (Ibata+, 2021)J/MNRAS/505/5978 : Gaia EDR3 view on Gal. globular clusters (Vasiliev+, 2021)J/ApJ/931/147 : Very metal-poor stars with LAMOST & Subaru. II. (Li+, 2022)J/A+A/665/A57 : The stellar halo near the Sun. I. (Lovdal+, 2022)J/ApJS/260/27 : R-Process Alliance: UV sp. of HD 222925 (Roederer+, 2022)J/ApJ/926/26 : Groups of metal-poor stars. I. (Shank+, 2022)J/ApJ/927/13 : Metal-poor stars observed with SALT/HRS. II. (Zepeda+, 2022)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/946/48https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/946/48http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/946/48https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/946/48https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/946/48http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/946/48GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/946/48/members (Basic properties (Table 2) and kinematics (Table 3) of the member stars of the clusters)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/946/48/members?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/946/48/members?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/946/48/members?GETtext/xml+votable180.050000true231.5044572-9.1941350.0055555555555555566/51 5580 5886 7186 7240 8221 8266 8340 8917 9574 10249 10476 10720 14674 15872 16462 16503 16569 16582 16815 17039 17245 17374 17406 17420 17516 17570 17579 18452 18550 18587 19070 19209 19861 20390 20882 22087 22635 22814 23107 23220 23304 24588 24683 25207 25369 25413 25482 25595 25696 25710 25737 25755 25835 25943 25959 26242 26994 27131 27147 27668 28740 28744 28938 30031 30184 30858 32352 32639 32949 33019 33200 33249 33391 33470 33696 33821 34019 34254 34952 34995 35105 35649 36587 36642 36788 36806 36825 37424 38316 38868 38919 38957 39084 39157 39328 39725 39809 40278 40322 41148 41244 41247 41721 42076 42308 42323 43367 43635 44035 44053 44304 44331 44445 44890 44926 44940 45309 45397 45564 45679 45743 45804 45818 46059 46090 46098 46155-46156 46309 46490 46493 46580 46659 46722 46851 46880 46902 47084 47169 47172 47201 47331 47353 47431 47458 47544 47608 47634 47650 47672 47776 47802 47854-47855 47941 47955 48501 48926 49001https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/946/48?format=asciiOpticaldefaultJ/ApJ/946/48/table1Properties of the clustersrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintDTC[1/30] Cluster identification (H22:DTC-) running sequence number (k) (1)meta.id;meta.mainintprimaryNm[1/18] Number of members in clustermeta.numberintJr[67/8014] Radial orbital action of cluster centerkpc.km/sarith.grad;phys.velocintJz[52/3390] Vertical orbital action of cluster centerkpc.km/sarith.grad;phys.velocintJphi[-3751/1757] Azimuthal orbital action of cluster centerkpc.km/sarith.grad;phys.velocintsigJr[8/153]? Dispersion of Jr in clusterkpc.km/sphys.dispMeasureintnullablesigJz[4/193]? Dispersion of Jz in clusterkpc.km/sphys.dispMeasureintnullablesigJphi[0/233]? Dispersion of Jphi in clusterkpc.km/sphys.dispMeasureintnullablesigk[24/150]? Average of Jr, Jz, & Jphi dispersionskpc.km/sphys.dispMeasure;stat.meanintnullable[Fe/H]Avg[-3.71/-1.39] Average log Fe/H number abundancelog(Sun)phys.abund.Fe;stat.meanfloatsig[Fe/H][0.05/0.83]? Dispersion of log Fe/H number abundancelog(Sun)stat.error;phys.abund.Fefloatnullableq[Fe/H][0.56/97.7]? Percentile rank of {sigma}<[Fe/H]>, see Section 7.1stat.error;phys.abund.Fefloatnullable[Eu/H]Avg[-2.71/-0.39] Average log Eu/H number abundancelog(Sun)phys.abund;stat.meanfloatsig[Eu/H][0.01/0.9]? Dispersion of log Eu/H number abundancelog(Sun)stat.error;phys.abundfloatnullableq[Eu/H][0.78/98]? Percentile rank of {sigma}[Eu/H], see Section 7.1stat.error;phys.abundfloatnullableCommComment (2)meta.noteJ/ApJ/946/48/membersBasic properties (Table 2) and kinematics (Table 3) of the member stars of the clustersSimbadNameSimbad column added by the CDSmeta.idcharnullableDTC[1/30] The cluster identifiermeta.id.parentintrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameStar namemeta.id;meta.mainchar[Fe/H][-3.71/-0.94] log Fe/H number abundancelog(Sun)phys.abund.Fefloat[Eu/H][-2.71/-0.14] log Eu/H number abundancelog(Sun)phys.abundfloat[Eu/Fe][0.7/2.23] log Eu/Fe number abundancelog(Sun)phys.abundfloatJr[0/8014] Radial orbital actionkpc.km/sarith.grad;phys.velocintJz[2/3462] Vertical orbital actionkpc.km/sarith.grad;phys.velocintJphi[-3751/1757] Azimuthal orbital actionkpc.km/sarith.grad;phys.velocintEnergy[-2.2/-0.56] Orbital energy100000km**2.s**-2phys.energyfloatplx/err[0.14/640] Gaia parallax/error valuestat.error;pos.parallax;arith.ratiofloatx[-16.1/3.1] Galactic X coordinatekpcpos.cartesian.x;pos.galacticfloaty[-7.1/4.6] Galactic Y coordinatekpcpos.cartesian.y;pos.galacticfloatz[-16.1/16.1] Galactic Z coordinatekpcpos.cartesian.z;pos.galacticfloatVx[-372.1/346.4] Velocity along the X coordinatekm/spos.cartesian.x;phys.velocfloatVy[-294/439.1] Velocity along the Y coordinatekm/spos.cartesian.y;phys.velocfloatVz[-434.4/408.2] Velocity along the Z coordinatekm/spos.cartesian.z;phys.velocfloatrperi[0.1/9.6] Perigalactic radiuskpcpos.distance;src.orbitalfloatrapo[3.27/129.5] Apogalactic radiuskpcpos.distance;src.orbitalfloatZmax[0.4/77.6] Maximum height above the Galactic planekpcpos.cartesian.z;pos.galactic;stat.maxfloate[0.04/0.99] Eccentricitysrc.orbital.eccentricityfloat_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.mainRefReference bibcodemeta.refchar