Pearls on a String: Numerous Stellar Clusters Strung Along the Same Orbit

Stars originate from the dense interstellar medium, which exhibits filamentary structure to scales of $\sim 1$ kpc in galaxies like our Milky Way. We explore quantitatively how much resulting large-scale correlation there is among different stellar clusters and associations \emph{orbit phase space}, characterized here by actions angles. As a starting point, we identified 55 prominent overdensities 6D space orbit (actions) orbital (angles), $\sim$ 2.8 million stars with radial velocities Gaia EDR3 $d \leq 800$ pc. then explored \emph{phase} distribution all sample same \emph{orbit} patch as any one these overdensities. find that very commonly numerous other distinct exist along orbits, pearls on string. These `pearls' range known loose, unrecognized associations. Among patches defined initial orbit-phase overdensity 50\% contain at least 8 additional orbital-phase 10 cataloged members; 20\% them 20 pearls. This contrast matching sampled smooth mock catalog, or offset nearby patches, where are only 2 (or 5, respectively) comparable Our findings quantify for first time common it star form phases nearly orbit. may eventually offer new way probe medium.