Resumo

PASQUATO, M.. Analytical Solutions for the Dynamical Clock A+ Indicator in a Toy Model of Pure Dynamical Friction. Rev. mex. astron. astrofis [online]. 2020, vol.56, n.1, pp.3-6.  Epub 19-Mar-2021. ISSN 0185-1101.  https://doi.org/10.22201/ia.01851101p.2020.56.01.01.

Blue straggler stars are more massive than the average star in globular clusters, as they originate from the merger of two stars. Consequently, they experience dynamical friction, progressively sinking to the cluster center. Recently, several indicators of the degree of dynamical relaxation of a globular cluster have been proposed, based on the observed radial distribution of blue straggler stars. The most successful is the Alessandrini indicator, or A+ for short, which is the integral of the cumulative distribution of the blue straggler stars minus that of a lighter reference population. A+ correlates with the dynamical age of a cluster both in realistic simulations and in observations. Here I calculate the temporal dependence of the A+ indicator analytically in a simplied model of the evolution of the blue straggler star distribution under dynamical friction only.

Palavras-chave : blue stragglers; globular clusters: general; methods: analytical.

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