The binary fraction in the globular cluster M10 (NGC 6254): comparing core and outer regions

TL;DR

This study measures the binary star fraction in globular cluster M10 across different regions, revealing a decrease from core to outskirts, and discusses implications for cluster dynamics and black hole presence.

Contribution

It provides a detailed radial profile of binary fraction in M10 using Hubble data, highlighting its role in cluster evolution without requiring an intermediate-mass black hole.

Findings

Binary fraction decreases from 14% in the core to 1.5% at outer regions.

Radial binary fraction trend aligns with similar clusters.

Binary fraction explains suppressed mass segregation.

Abstract

We study the binary fraction of the globular cluster M10 (NGC 6254) as a function of radius from the cluster core to the outskirts, by means of a quan- titative analysis of the color distribution of stars relative to the fiducial main sequence. By taking advantage of two data-sets, acquired with the Advanced Camera for Survey and the Wide Field Planetary Camera 2 on board the Hubble Space Telescope, we have studied both the core and the external regions of the cluster. The binary fraction is found to decrease from 14% within the core, to 1.5% in a region between 1 and 2 half-mass radii from the cluster centre. Such a trend and the derived values are in agreement with previous results ob- tained in clusters of comparable total magnitude. The estimated binary fraction is sufficient to account for the suppression of mass segregation observed in M10, without any need to invoke the presence of an intermediate-mass black hole in its centre.