Fewer Companions in the Crowd: The Low Close Binary Fraction in Globular Clusters from Gaia RVS
arXiv:2507.00131 · doi:10.1093/mnras/staf1102
Abstract
In dense environments like globular clusters (GCs), dynamical interactions can disrupt or harden close binaries, nonetheless, detailed comparisons with field binary fractions remain limited. Here, we present an analysis of the close binary fraction in a carefully selected sample of field stars and 10 GCs using Gaia Radial Velocity Spectrometer (RVS) data, which is among the largest samples of GCs analysed using multi-epoch spectroscopy to date. By assessing the peak-to-peak variations of the sources' radial velocity (RV), we estimate the close binary fractions through a method that fits the distribution as the product of two Gaussian distributions. By applying the same RV-variability method to both cluster members and field stars, we ensure a homogeneous and inclusive comparison between the two environments. Despite matching stellar parameters between the field and GC samples, our findings confirm that GCs possess a significantly lower close binary fraction than field stars. Interestingly, we do not detect any clear trend of binary fraction with cluster metallicity; metal-rich and metal-poor GCs are uniformly binary-poor (within uncertainties). We discuss possible interpretations, including dynamical hardening in dense environments and the effects of common envelope evolution, which may lead to companion accretion or merger events.
arXiv comment8 pages, 6 figures. Resubmitted to MNRAS after addressing referee's comments
References in corpus (34)
- The Astropy Project: Sustaining and Growing a Community-oriented Open-source Project and the Latest Major Release (v5.0) of the Core Package
- Modules for Experiments in Stellar Astrophysics (MESA)
- MESA Isochrones and Stellar Tracks (MIST). I: Solar-Scaled Models
- MESA Isochrones and Stellar Tracks (MIST) 0: Methods for the construction of stellar isochrones
- A Survey of Stellar Families: Multiplicity of Solar-Type Stars
- Accurate masses and radii of normal stars: modern results and applications
- Common Envelope Evolution: Where we stand and how we can move forward
- A catalogue of masses, structural parameters and velocity dispersion profiles of 112 Milky Way globular clusters
- Gaia EDR3 view on Galactic globular clusters
- The ACS Survey of Galactic Globular Clusters. XII. Photometric Binaries along the Main-Sequence
- Gaia Data Release 3 Properties and validation of the radial velocities
- Gaia Data Release 3: Stellar multiplicity, a teaser for the hidden treasure
- The Close Binary Fraction of Solar-type Stars is Strongly Anti-correlated with Metallicity
- From dawn till disk: Milky Way's turbulent youth revealed by the APOGEE+Gaia data
- The Evolution of Binary Fractions in Globular Clusters
- The life cycle of star cluster in a tidal field
- A stellar census in globular clusters with MUSE: Binaries in NGC 3201
- Formation of close binaries by disc fragmentation and migration, and its statistical modeling
- Formation and evolution of compact binaries in globular clusters: I.Binaries with white dwarfs
- Close Binary Companions to APOGEE DR16 Stars: 20,000 Binary-star Systems Across the Color-Magnitude Diagram
- The core binary fractions of star clusters from realistic simulations
- A Correlation between Blue Straggler and Binary Fractions in the core of Galactic Globular Clusters
- The incidence of binaries in Globular Cluster stellar populations
- A search for spectroscopic binaries in the galactic globular cluster M4. Based on 5973 individual spectra collected at VLT
- The binary fraction in the globular cluster M10 (NGC 6254): comparing core and outer regions
- Gaia Data Release 3: Hot-star radial velocities
- The binary content of multiple populations in NGC 3201
- Is a binary fraction-age relation responsible for the lack of EHB binaries in globular clusters?
- Features of Gaia DR3 Spectroscopic Binaries I. Tidal circularization of Main-Sequence Stars
- Gaia Focused Product Release: Sources from Service Interface Function image analysis -- Half a million new sources in omega Centauri
- Predicting metallicities and carbon abundances from Gaia XP spectra for (carbon-enhanced) metal-poor stars
- Binary properties of the globular cluster 47 Tuc (NGC 104). A dearth of short-period binaries
- Studying Binary Systems in Omega Centauri with MUSE. I. Detection of Spectroscopic Binaries
- Kinematics of metallicity populations in Omega Centauri using Gaia Focused Product Release and Hubble Space Telescope