Probing the role of dynamical friction in shaping the BSS radial distribution. I - Semi-analytical models and preliminary N-body simulations

Abstract

We present semi-analytical models and simplified $N$-body simulations with $10^4$ and $10^5$ particles aimed at probing the role of dynamical friction (DF) in determining the radial distribution of Blue Straggler Stars (BSSs) in globular clusters. The semi-analytical models show that DF (which is the only evolutionary mechanism at work) is responsible for the formation of a bimodal distribution with a dip progressively moving toward the external regions of the cluster. However, these models fail to reproduce the formation of the long-lived central peak observed in all dynamically evolved clusters. The results of $N$-body simulations confirm the formation of a sharp central peak, which remains as a stable feature over the time regardless of the initial concentration of the system. In spite of a noisy behavior, a bimodal distribution forms in many cases, with the size of the dip increasing as a function of time. In the most advanced stages the distribution becomes monotonic. These results are in agreement with the observations. Also the shape of the peak and the location of the minimum (which in most of the cases is within 10 core radii) turn out to be consistent with observational results. For a more detailed and close comparison with observations, including a proper calibration of the timescales of the dynamical processes driving the evolution of the BSS spatial distribution, more realistic simulations will be necessary.

Accepted for publication by ApJ; 11 pages, 11 figures

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Cited by in corpus (7)

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• The "dynamical clock": dating the internal dynamical evolution of star clusters with Blue Straggler Stars
• Determination of dynamical ages of open clusters through the A${}^{+}$ parameter -- I
• Introducing a new multi-particle collision method for the evolution of dense stellar systems. Crash-test N-body simulations
• Relativistic dynamical friction in stellar systems
• A disturbance in the force. How force fluctuations hinder dynamical friction and induce core stalling
• Taking apart the dynamical clock. Fat-tailed dynamical kicks shape the blue-straggler star bimodality