Confusing binaries: the role of stellar binaries in biasing disk properties in the Galactic Center

Abstract

The population of young stars near the Supermassive black hole (SMBH) in the Galactic Center (GC) has presented an unexpected challenge to theories of star formation. Kinematics measurements of these stars have revealed a stellar disk structure (with an apparent 20% disk membership) that has provided important clues to the origin of these mysterious young stars. However many of the apparent disk properties are difficult to explain, including the low disk membership fraction and the high eccentricities, given the youth of this population. Thus far, all efforts to derive the properties of this disk have made the simplifying assumption that stars at the GC are single stars. Nevertheless, stellar binaries are prevalent in our Galaxy, and recent investigations suggested that they may also be abundant in the Galactic Center. Here we show that binaries in the disk can largely alter the apparent orbital properties of the disk. The motion of binary members around each other adds a velocity component, which can be comparable to the magnitude of the velocity around the SMBH in the GC. Thus neglecting the contribution of binaries can significantly vary the inferred stars' orbital properties. While the disk orientation is unaffected the apparent disk's 2D width is increased to about 11.2deg, similar to the observed width. For a population of stars orbiting the SMBH with zero eccentricity, unaccounted for binaries will create a wide apparent eccentricity distribution with an average of 0.23.This is consistent with the observed average eccentricity of the stars' in the disk. We suggest that this high eccentricity value, which poses a theoretical challenge, may be an artifact of binary stars. Finally our results suggest that the actual disk membership might be significantly higher than the one inferred by observations that ignore the contribution of binaries, alleviating another theoretical challenge.

Accepted to ApJ Lett, 5 figures, 8 pages

References in corpus (18)

• Binary interaction dominates the evolution of massive stars
• The Two Young Star Disks in the Central Parsec of the Galaxy: Properties, Dynamics and Formation
• Gravitational waves from scattering of stellar-mass black holes in galactic nuclei
• An Update on Monitoring Stellar Orbits in the Galactic Center
• Starbursts near supermassive black holes: young stars in the Galactic Center, and gravitational waves in LISA band
• An Improved Distance and Mass Estimate for Sgr A* from a Multistar Orbit Analysis
• Mergers and Obliquities in Stellar Triples
• Simulations of the formation of stellar discs in the Galactic centre via cloud-cloud collisions
• Detection of Galactic Center source G2 at 3.8 $\mu$m during periapse passage
• Dynamical evolution of the young stars in the Galactic center: N-body simulations of the S-stars
• Secular Evolution Of Binaries Near Massive Black Holes: Formation of compact binaries, merger/collision products and G2-like objects
• Runaway and hypervelocity stars in the Galactic halo: Binary rejuvenation and triple disruption
• Photometric Stellar Variability in the Galactic Center
• The effect of binaries on the dynamical mass determination of star clusters
• Hypervelocity Collisions of Binary Stars at the Galactic Centre
• Cluster Core Dynamics at the Galactic Center
• The Post-Periapse Evolution of Galactic Center Source G1: The second case of a resolved tidal interaction with a supermassive black hole
• Eclipsing Stellar Binaries in the Galactic Center

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• The Inner 2 pc of Sagittarius A*: Simulations of the Circumnuclear Disk and Multiphase Gas Accretion in the Galactic Center
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• Detecting gravitational-wave bursts from black hole binaries in the Galactic Center with LISA
• The mean free path approximation and stellar collisions in star clusters: Numerical exploration of the analytic rates and the role of perturbations on binary star mergers
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