Catching a Milky Way open cluster in its last breath

ANDRÉS E. PIATTI

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2023 vol. 519 p. 6239 - 6245

0035-8711

Theoretical models have suggested peculiar velocity dispersion profiles of star clustersfacing dissolution. They predicted that, besides bound stars that still belong to thestar cluster, and unbound ones already stripped off, there is an intermediate popu-lation of stars that having acquired the enough energy to escape the cluster are stillwithin the cluster Jacobi radius. Both, potential escapers and unbound stars, showhot kinematics, not observed along tidal tails of star clusters. We report on the firstevidence of an open cluster with stars crossing such a transitional scenario, namely:ASCC 92. The open cluster gathers nearly 10 percent of its initial total mass, and ismoving toward Galactic regions affected by higher interstellar absorption. Precisely,the obscured appearance of the cluster could have hampered disentangling its trueinternal dynamical evolutionary stage, previously.