The Progeny of Stellar Dynamics and Stellar Evolution within an N-body model of NGC 188

TL;DR

This paper presents a detailed N-body simulation of the old open cluster NGC 188, integrating observed initial binary populations from M35, and compares the simulation results with actual observations to understand stellar dynamics and evolution.

Contribution

First N-body simulation of an open cluster using observed initial binary populations from a specific cluster, M35, to improve realism and comparison accuracy.

Findings

Simulation reproduces key features of NGC 188's color-magnitude diagram.

Binary period and eccentricity distributions match observations closely.

Discrepancies identified suggest areas for model refinement.

Abstract

We present a direct N-body simulation modeling the evolution of the old (7 Gyr) open cluster NGC 188. This is the first N-body open cluster simulation whose initial binary population is directly defined by observations of a specific open cluster: M35 (150 Myr). We compare the simulated color-magnitude diagram at 7 Gyr to that of NGC 188, and discuss the blue stragglers produced in the simulation. We compare the solar-type main sequence binary period and eccentricity distributions of the simulation to detailed observations of similar binaries in NGC 188. These results demonstrate the importance of detailed observations in guiding N-body open cluster simulations. Finally, we discuss the implications of a few discrepancies between the NGC 188 model and observations and suggest a few methods for bringing N-body open cluster simulations into better agreement with observations.