文章基本信息

标题：Mergers, tidal interactions, and mass exchange in a population of disc globular clusters
其他标题：II. Long-term evolution
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作者：Alessandra Mastrobuono-Battisti ; Sergey Khoperskov ; Paola Di Matteo 等
期刊名称：Astronomy & Astrophysics
印刷版ISSN：0004-6361
电子版ISSN：1432-0746
出版年度：2019
卷号：622
DOI：10.1051/0004-6361/201834087
语种：English
出版社：EDP Sciences
摘要：Globular clusters (GCs), the oldest stellar systems observed in the Milky Way, have long been considered single stellar populations. As such, they provided an ideal laboratory to understand stellar dynamics and primordial star formation processes. However, during the last two decades, observations have unveiled their true, complex nature. Beside their pristine stars, GCs host one or more helium enriched and possibly younger stellar populations whose formation mechanism is still unknown. Even more puzzling is the existence of GCs showing star-by-star iron spreads. Using detailedN-body simulations we explore the hypothesis that these anomalies in metallicity could be the result of mutual stripping and mergers between a primordial population of disc GCs. In the first paper of this series we proved, both with analytical arguments and short-termN-body simulations, that disc GCs have larger fly-by and close-encounter rates with respect to halo clusters. These interactions lead to mass exchange and even mergers that form new GCs, possibly showing metallicity spreads. Here, by means of long-term directN-body simulations, we provide predictions on the dynamical properties of GCs that have undergone these processes. The comparison of our predictions with currently available and future observational data could provide insights into the origin of GCs and the Milky Way build-up history as a whole.
关键词：enGalaxy: diskGalaxy: evolutionGalaxy: formationGalaxy: kinematics and dynamicsglobular clusters: general