Effects of the environment on the multiplicity properties of stars in the STARFORGE simulations

Abstract

Most observed stars are part of a multiple star system, but the formation of such systems and the role of environment and various physical processes is still poorly understood. We present a suite of radiation-magnetohydrodynamic simulations of star-forming molecular clouds from the STARFORGE project that include stellar feedback with varied initial surface density, magnetic fields, level of turbulence, metallicity, interstellar radiation field, simulation geometry and turbulent driving. In our fiducial cloud the raw simulation data reproduces the observed multiplicity fractions for Solar-type and higher mass stars, similar to previous works. However, after correcting for observational incompleteness the simulation under-predicts these values. The discrepancy is likely due to the lack of disk fragmentation, as the simulation only resolves multiples that form either through capture or core fragmentation. The raw mass distribution of companions is consistent with randomly drawing from the initial mass function for the companions of $>1{\mathrm{M}}_{\odot }$ stars, however, accounting for observational incompleteness produces a flatter distribution similar to observations. We show that stellar multiplicity changes as the cloud evolves and anti-correlates with stellar density. This relationship also explains most multiplicity variations between runs, i.e., variations in the initial conditions that increase stellar density (increased surface density, reduced turbulence) decrease multiplicity. While other parameters, such as metallicity, interstellar radiation, and geometry significantly affect the star formation history or the IMF, varying them produces no clear trend in stellar multiplicity properties.

20 pages, 21 figures, submitted to MNRAS

References in corpus (18)

• A Minimum Column Density of 1 g cm^-2 for Massive Star Formation
• The Effects of Radiative Transfer on Low-Mass Star Formation
• The Importance of Radiative Feedback for the Stellar Initial Mass Function
• Mapping the Shores of the Brown Dwarf Desert I.: Upper Scorpius
• STARFORGE: Toward a comprehensive numerical model of star cluster formation and feedback
• The dynamics and outcome of star formation with jets, radiation, winds, and supernovae in concert
• The statistical properties of stars and their dependence on metallicity
• The Turbulent Origin of Outflow and Spin Misalignment in Multiple Star Systems
• A model for the formation of stellar associations and clusters from giant molecular clouds
• The Formation and Evolution of Wide-Orbit Stellar Multiples In Magnetized Clouds
• The Formation of Stellar Clusters in Magnetized, Filamentary Infrared Dark Clouds
• Binaries in the field: fossils of the star formation process?
• The VLA/ALMA Nascent Disk and Multiplicity (VANDAM) Survey of Orion Protostars V. A Characterization of Protostellar Multiplicity
• The Mass-Size Relation and the Constancy of GMC Surface Densities in the Milky Way
• The IMF and multiplicity of stars from gravity, turbulence, magnetic fields, radiation and outflow feedback
• Can magnetized turbulence set the mass scale of stars?
• Continuity of accretion from clumps to Class 0 high-mass protostars in SDC335
• The impact of episodic outflow feedback on stellar multiplicity and the star formation efficiency

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• Wide-binary eccentricity distribution in young star clusters: dependence on the binary separation and mass
• The bound origin of low-mass stellar binaries
• Stellar masses and mass ratios for Gaia open cluster members
• The fragmentation of molecular clouds in starburst environments
• Non-ideal MHD and protostellar feedback effects on disc formation and evolution in numerical simulations of star cluster formation
• Formation of massive multiple-star systems: early migration and mergers