The correlation between blue straggler and binary fractions in the core of Galactic globular clusters

  title={The correlation between blue straggler and binary fractions in the core of Galactic globular clusters},
  author={Antonio Sollima and Barbara Lanzoni and Giacomo Beccari and Francesco R. Ferraro and Flavio Fusi Pecci},
  journal={Astronomy and Astrophysics},
Context. Blue stragglers stars (BSSs) are thought to form in globular clusters by two main formation channels: $i)$ mergers induced by stellar collisions; and $ii)$ coalescence or mass transfer between companions in binary systems. The detailed study of the BSS properties is therefore crucial for understanding the binary evolution mechanisms and the complex interplay between dynamics and stellar evolution in dense stellar systems. Aims. We present the first comparison between the BSS specific… 

Figures and Tables from this paper

The origins of blue stragglers and binarity in globular clusters
This work uses newly available empirical binary fractions for globular clusters to carry out a more direct test of the binary evolution hypothesis, but also of collisional channels that involve binary stars.
Stellar Collisions and Blue Straggler Stars in Dense Globular Clusters
Blue straggler stars (BSSs) are abundantly observed in all Galactic globular clusters (GGCs) where data exist. However, observations alone cannot reveal the relative importance of various formation
A binary origin for ‘blue stragglers’ in globular clusters
It is reported that there is a clear, but sublinear, correlation between the number of blue stragglers found in a cluster core and the total stellar mass contained within it, and it is concluded that most blue stragglers, even those found in cluster cores, come from binary systems.
Two separated sequences of blue straggler stars (BSSs) have been revealed by Ferraro et al. in the color–magnitude diagram (CMD) of the Milky Way globular cluster M30. Their presence has been
An analytic model for blue straggler formation in globular clusters
We present an analytic model for blue straggler formation in globular clusters. We assume that blue stragglers are formed only through stellar collisions and binary star evolution, and compare our
Blue Stragglers in Globular Clusters: Observations, Statistics and Physics
This chapter explores how we might use the observed statistics of blue stragglers in globular clusters to shed light on their formation. This means we will touch on topics also discussed elsewhere in
Spectroscopy of Binaries in Globular Clusters
The natural constants in the universe are adjusted so that dense and massive star forming regions can end up in gravitational bound star clusters, called globular clusters. These objects are found in
We present a homogeneous study of blue straggler stars across 10 outer halo globular clusters, 3 classical dwarf spheroidal galaxies, and 9 ultra-faint galaxies based on deep and wide-field
Formation and Evolution of Blue Stragglers in 47 Tucanae
Blue stragglers (BSS) are stars whose position in the color–magnitude diagram (CMD) places them above the main sequence (MS) turn-off (TO) point of a star cluster. Using data from the core of 47 Tuc
MOCCA code for star cluster simulations - V. Initial globular cluster conditions influence on blue stragglers
The paper presents an analysis of properties of populations of blue stragglers (BSs) in evolving globular clusters, based on numerical simulations done with the MOCCA code for various initial


Relative Frequencies of Blue Stragglers in Galactic Globular Clusters: Constraints for the Formation Mechanisms
We discuss the main properties of the Galactic globular cluster (GC) blue straggler stars (BSSs), as inferred from our new catalog containing nearly 3000 BSSs. The catalog has been extracted from the
The radial distribution of blue straggler stars and the nature of their progenitors
The origin of blue straggler stars (BSS) in globular clusters (GCs) is still not fully understood: they can form from stellar collisions, or through mass transfer in isolated, primordial binaries
The fraction of binary systems in the core of 13 low-density Galactic globular clusters
By analysing the colour distribution of main-sequence stars, the minimum fraction of binary systems required to reproduce the observed colour–magnitude diagram morphologies was derived, finding that all the analysed globular clusters contain a minimum binary fraction larger than 6 per cent within the core radius.
Search and analysis of blue straggler stars in open clusters
Aims. This paper presents a new homogeneous catalogue of blue straggler stars (BSS) in Galactic open clusters. Methods. Photometric data for 216 clusters were collected from the literature and 2782
Blue Stragglers in Low-Luminosity Star Clusters
We examine the blue straggler populations of 13 low-luminosity (M ≳ -6) globular clusters and two old open clusters. These clusters test blue straggler formation in environments intermediate between
The evolution of binary fractions in globular clusters
The combination of stellar evolution and dynamical interactions (binary–single and binary–binary) leads to a rapid depletion of the binary population in the cluster core, suggesting that “realistic models” should incorporate much larger initial binary fractions.
Blue straggler production in globular clusters
Recent Hubble Space Telescope observations of a large sample of globular clusters reveal that every cluster contains between 40 and 400 blue stragglers.The population does not correlate with either
The blue plume population in dwarf spheroidal galaxies - Genuine blue stragglers or young stellar population?
Aims. Blue stragglers (BSS) in the Milky Way field and globular/open clusters are thought to be the product of either primordial or collisional binary systems. In the context of dwarf spheroidal
Building Up the Globular Cluster System of the Milky Way: The Contribution of the Sagittarius Galaxy
We demonstrate that there is a clear statistical correlation between the (X, Y, Z, Vr) phase-space distribution of the outer halo Galactic globular clusters (having 10 kpc ≤ RGC ≤ 40 kpc) and the
Where the Blue Stragglers Roam: Searching for a Link between Formation and Environment
The formation of blue stragglers is still not completely understood, particularly the relationship between formation environment and mechanism. We use a large, homogeneous sample of blue stragglers