The extended halo and tidal tails of the old open cluster NGC 2112.

This article focuses on the spatial structure and tidal tails of the nearby old open cluster NGC 2112, located approximately 1100 parsecs from the Sun and about 1.2 billion years old. Using Gaia Data Release 3 astrometric data and the DBSCAN clustering algorithm, the study identifies over 1200 reliable cluster members and reveals a two-component structure consisting of a near-circular core and an elongated halo influenced by the Galactic tidal field. The authors detect tidal tails extending roughly 36 parsecs, aligned with the cluster's orbit, containing various stellar types including high-mass stars such as main-sequence turn-off and blue straggler stars, suggesting that mechanisms beyond simple two-body relaxation contribute to their formation. The tidal tails are estimated to have formed within the last ~30 million years, providing insights into the dynamical disruption processes affecting old open clusters in the solar neighborhood.