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We derive dynamical parameters for a large sample of 446 $r$-process-enhanced(RPE) metal-poor stars in the halo and disk systems of the Milky Way, based ondata releases from the $R$-Process Alliance, supplemented by additionalliterature samples. This sample represents more than a ten-fold increase insize relative to that previously considered by Roederer et al., and, by design,covers a larger range of $r$-process-element enrichment levels. We test anumber of clustering analysis methods on the derived orbital energies and otherdynamical parameters for this sample, ultimately deciding on application of theHDBSCAN algorithm, which obtains 30 individual Chemo-Dynamically Tagged Groups(CDTGs); 21 contain between 3 and 5 stars, and 9 contain between 6 and 12stars. Even though the clustering was performed solely on the basis of theirdynamical properties, the stars in these CDTGs exhibit statisticallysignificant similarities in their metallicity ([Fe/H]), carbonicity ([C/Fe]),and neutron-capture element ratios ([Sr/Fe], [Ba/Fe], and [Eu/Fe]). Theseresults demonstrate that the RPE stars in these CDTGs have likely experiencedcommon chemical-evolution histories, presumably in their parent satellitegalaxies or globular clusters, prior to being disrupted into the Milky Way'shalo. We also confirm the previous claim that the orbits of the RPE starspreferentially exhibit pericentric distances that are substantially lower thanthe present distances of surviving ultra-faint dwarf and canonical dwarfspheroidal galaxies, consistent with the disruption hypothesis. The deriveddynamical parameters for several of our CDTGs indicate their association withpreviously known substructures, Dynamically Tagged Groups, and RPE Groups.

The R-Process Alliance: Chemo-Dynamically Tagged Groups of Halo $r$-Process-Enhanced Stars Reveal a Shared Chemical-Evolution History