2013/01/23 by Mark Gieles, Gieles, Mark
Earth and Planetary Sciences · Physics and Astronomy · #Astro and Planetary Science #Astrophysics of Galaxies (astro-ph.GA) #FOS: Physical sciences #Geology and Paleoclimatology Research #Stellar, planetary, and galactic studies #astro-ph.GA
paper · pdf · doi:10.48550/arxiv.1301.5445
5 pages, 1 figure. To appear in the proceedings of the conference `Reading the book of globular clusters with the lens of stellar evolution', Rome, Nov. 26-28, 2012, to be published in Memorie della Societa Astronomica Italiana, Eds. Paolo Ventura and Corinne Charbonnel
arxiv created 2013/01/23 · openalex publication_date 2013/01/23 · arxiv updated 2013/01/24 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We present a simple theory for the evolution of initially compact clusters in a tidal field. The fundamental ingredient of the model is that a cluster conducts a constant fraction of its own energy through the half-mass radius by two-body interactions every half-mass relaxation time. This energy is produced in a self-regulative way in the core by an (unspecified) energy source. We find that the half-mass radius increases during the first part (roughly half) of the evolution and decreases in the second half, while the escape rate is constant and set by the tidal field. We present evolutionary tracks and isochrones for clusters in terms of cluster half-mass density, cluster mass and galacto-centric radius. We find substantial agreement between model isochrones and Milky Way globular cluster parameters, which suggests that there is a balance between the flow of energy and the central energy production for almost all globular clusters. We also find that the majority of the globular clusters are still expanding towards their tidal radius. Finally, a fast code for cluster evolution is presented.