Formation of Wide Binaries by Turbulent Fragmentation

Abstract

Understanding the formation of wide binary systems of very low mass stars (M $\le$ 0.1 Msun) is challenging. The most obvious route is via widely separated low-mass collapsing fragments produced through turbulent fragmentation of a molecular core. However, close binaries/multiples from disk fragmentation can also evolve to wide binaries over a few initial crossing times of the stellar cluster through tidal evolution. Finding an isolated low mass wide binary system in the earliest stage of formation, before tidal evolution could occur, would prove that turbulent fragmentation is a viable mechanism for (very) low mass wide binaries. Here we report high resolution ALMA observations of a known wide-separation protostellar binary, showing that each component has a circumstellar disk. The system is too young to have evolved from a close binary and the disk axes are misaligned, providing strong support for the turbulent fragmentation model. Masses of both stars are derived from the Keplerian rotation of the disks; both are very low mass stars.

Published in Nature Astronomy

References in corpus (10)

• A Triple Protostar System Formed via Fragmentation of a Gravitationally Unstable Disk
• The Spitzer c2d Survey of Nearby Dense Cores: I: First Direct Detection of the Embedded Source in IRAM 04191+1522
• Misaligned Protoplanetary Disks in a Young Binary System
• The Evolution of the Multiplicity of Embedded Protostars I: Sample Properties and Binary Detections
• The Turbulent Origin of Outflow and Spin Misalignment in Multiple Star Systems
• Discovery of a wide companion near the deuterium burning mass limit in the Upper Scorpius association
• ALMA Observations of the T Tauri Binary System AS 205: Evidence for Molecular Winds and/or Binary Interactions
• ALMA observations of a misaligned binary protoplanetary disk system in Orion
• Synthetic Observations of Magnetic Fields in Protostellar Cores
• The Taurus Boundary of Stellar/Substellar (TBOSS) Survey I: far-IR disk emission measured with Herschel

Cited by in corpus (15)

• On the diversity and statistical properties of protostellar discs
• Interferometric observations of magnetic fields in forming stars
• Identical or fraternal twins? : The chemical homogeneity of wide binaries from Gaia DR2
• Binary Stars in the New Millennium
• ALMA Survey of Orion Planck Galactic Cold Clumps (ALMASOP) II. Survey overview: a first look at 1.3 mm continuum maps and molecular outflows
• FRagmentation and Evolution of dense cores Judged by ALMA (FREJA). I (Overview). Inner $\sim$1000 au structures of prestellar/protostellar cores in Taurus
• Implementing Primordial Binaries in Simulations of Star Cluster Formation with a Hybrid MHD and Direct N-Body Method
• The ALMA-PILS survey: Gas dynamics in IRAS 16293$-$2422 and the connection between its two protostars
• FAUST III. Misaligned rotations of the envelope, outflow, and disks in the multiple protostellar system of VLA 1623$-$2417
• Very wide companion fraction from Gaia DR2: a weak or no enhancement for hot jupiter hosts, and a strong enhancement for contact binaries
• Chemical Properties of the Local Disk and Halo. II. Abundances of 3745 M dwarfs and Subdwarfs from Improved Model Fitting of Low-Resolution Spectra
• Precessing Jet and Large Dust Grains in the V380 Ori NE Star-forming Region
• Saturation level of turbulence in collapsing gas clouds
• Chemodynamics of metal-poor wide binaries in the Galactic halo: Association with the Sequoia event
• When did the initial mass function become bottom-heavy?