The eccentricity distribution of wide binaries and their individual measurements

Abstract

Eccentricity of wide binaries is difficult to measure due to their long orbital periods. With Gaia's high-precision astrometric measurements, eccentricity of a wide binary can be constrained by the angle between the separation vector and the relative velocity vector (the $v$-$r$ angle). In this paper, by using the $v$-$r$ angles of wide binaries in Gaia Early Data Release 3, we develop a Bayesian approach to measure the eccentricity distribution as a function of binary separations. Furthermore, we infer the eccentricities of individual wide binaries and make them publicly available. Our results show that the eccentricity distribution of wide binaries at $10^2$ AU is close to uniform and becomes superthermal at $>10^3$ AU, suggesting two formation mechanisms dominating at different separation regimes. The close binary formation, most likely disk fragmentation, results in a uniform eccentricity distribution at $<10^2$ AU. The wide binary formation that leads to highly eccentric wide binaries at $>10^3$ AU may be turbulent fragmentation and/or the dynamical unfolding of compact triples. With Gaia, measuring eccentricities is now possible for a large number of wide binaries, opening a new window to understanding binary formation and evolution.

arXiv commentAccepted for publication in MNRAS. Fig. 7 is the key result. The online catalog of individual eccentricity measurements is available at: https://drive.google.com/file/d/11D4FeLxQjOaNfP8tw5DAKANt2A7zLbpn/view?usp=sharing. The codes and pre-computed grid are available at: https://github.com/HC-Hwang/Eccentricity-of-wide-binaries

References in corpus (63)

• SciPy 1.0--Fundamental Algorithms for Scientific Computing in Python
• Array Programming with NumPy
• Astropy: A Community Python Package for Astronomy
• emcee: The MCMC Hammer
• The Astropy Project: Building an inclusive, open-science project and status of the v2.0 core package
• A Survey of Stellar Families: Multiplicity of Solar-Type Stars
• Shrinking binary and planetary orbits by Kozai cycles with tidal friction
• Stellar Multiplicity
• Mind your Ps and Qs: the Interrelation between Period (P) and Mass-ratio (Q) Distributions of Binary Stars
• The Disk Substructures at High Angular Resolution Project (DSHARP): I. Motivation, Sample, Calibration, and Overview
• The Eccentric Kozai-Lidov Effect and Its Applications
• Origins of Hot Jupiters
• Hot Jupiters from Secular Planet--Planet Interactions
• The Disk Substructures at High Angular Resolution Project (DSHARP): II. Characteristics of Annular Substructures
• A million binaries from Gaia eDR3: sample selection and validation of Gaia parallax uncertainties
• Stellar, Brown Dwarf, and Multiple Star Properties from Hydrodynamical Simulations of Star Cluster Formation
• Evolution in Binary and Triple Stars, with an application to SS Lac
• Secular Dynamics in Hierarchical Three-Body Systems
• Radiation-Hydrodynamic Simulations of Collapse and Fragmentation in Massive Protostellar Cores
• Unresolved stellar companions with Gaia DR2 astrometry
• From binaries to multiples II: hierarchical multiplicity of F and G dwarfs
• On the Role of Disks in the Formation of Stellar Systems: A Numerical Parameter Study of Rapid Accretion
• The Formation of Close Binary Systems by Dynamical Interactions and Orbital Decay
• The Formation of Low-Mass Binary Star Systems Via Turbulent Fragmentation
• The Close Binary Fraction of Solar-type Stars is Strongly Anti-correlated with Metallicity
• Mergers and Obliquities in Stellar Triples
• Inferring the eccentricity distribution
• Formation of the Widest Binaries from Dynamical Unfolding of Triple Systems
• The formation of very wide binaries during the star cluster dissolution phase
• Fragmentation of Massive Protostellar Disks
• Global Models for the Evolution of Embedded, Accreting Protostellar Disks
• Circumstellar and Circumbinary Disks in Eccentric Stellar Binaries
• The Evolution of Wide Binary Stars
• Comoving stars in Gaia DR1: An abundance of very wide separation co-moving pairs
• Formation of close binaries by disc fragmentation and migration, and its statistical modeling
• Stellar Multiplicity Meets Stellar Evolution And Metallicity: The APOGEE View
• Tidal dissipation in binary systems
• Imprints of white dwarf recoil in the separation distribution of Gaia wide binaries
• Impact of Binary Stars on Planet Statistics -- I. Planet Occurrence Rates, Trends with Stellar Mass, and Wide Companions to Hot Jupiter Hosts
• Discovery of an equal-mass "twin" binary population reaching 1000+ AU separations
• Eccentricity distribution of wide binaries
• Hot Jupiters are Destroyed by Tides While Their Host Stars are on the Main Sequence
• The statistical properties of stars and their dependence on metallicity: the effects of opacity
• Dense Stellar Populations: Initial Conditions
• Identical or fraternal twins? : The chemical homogeneity of wide binaries from Gaia DR2
• The formation of permanent soft binaries in dispersing clusters
• The Separation Distribution of Ultra-Wide Binaries across Galactic Populations
• The evolution of large cavities and disc eccentricity in circumbinary discs
• The wide binary fraction of solar-type stars: emergence of metallicity dependence at a < 200 AU
• The SUPERWIDE Catalog: A Catalog of 99,203 Wide Binaries Found in Gaia and Supplemented by the SUPERBLINK High Proper Motion Catalog
• Testing Gravity with wide binary stars like $\alpha$ Centauri
• The Close Binary Fraction as a Function of Stellar Parameters in APOGEE: A Strong Anti-Correlation With $\alpha$ Abundances
• Testing Modified Gravity with Wide Binaries in GAIA DR2
• Formation of wide binary stars from adjacent cores
• In Search of the Thermal Eccentricity Distribution
• Eccentricity distribution of wide low-mass binaries
• Stellar Companions to TESS Objects of Interest: A Test of Planet-Companion Alignment
• Lifetime of short-period binaries measured from their Galactic kinematics
• The non-monotonic, strong metallicity dependence of the wide-binary fraction
• Binary companions of evolved stars in APOGEE DR14: Orbital circularization
• Secular dynamics of binaries in stellar clusters I: general formulation and dependence on cluster potential
• The geometric challenge of testing gravity with wide binaries
• Very wide companion fraction from Gaia DR2: a weak or no enhancement for hot jupiter hosts, and a strong enhancement for contact binaries