Affiliation:
1. Department of Physics and Astronomy, University of Exeter , Stocker Road, Exeter EX4 4QL, UK
Abstract
ABSTRACT
We report the statistical properties of stars and brown dwarfs obtained from three radiation hydrodynamical simulations of star cluster formation with metallicities of 1, 1/10, and 1/100 of the solar value. The star-forming clouds are subjected to cosmic microwave background radiation that is appropriate for star formation at a redshift z = 5. The results from the three calculations are compared to each other, and to similar previously published calculations that had levels of background radiation appropriate for present-day (z = 0) star formation. Each of the calculations treats dust and gas temperatures separately and includes a thermochemical model of the diffuse interstellar medium. We find that whereas the stellar mass distribution is insensitive to the metallicity for present-day star formation, at z = 5 the characteristic stellar mass increases with increasing metallicity and the mass distribution has a deficit of brown dwarfs and low-mass stars at solar metallicity compared to the Galactic initial mass function. We also find that the multiplicity of M-dwarfs decreases with increasing metallicity at z = 5. These effects are a result of metal-rich gas being unable to cool to as low temperatures at z = 5 compared to at z = 0 due to the hotter cosmic microwave background radiation, which inhibits fragmentation at high densities.
Funder
European Research Council
Information Technology Center, Nagoya University
Science and Technology Facilities Council
Center for High Performance Computing
Department for Business, Innovation and Skills
BIS
National Science Foundation
Publisher
Oxford University Press (OUP)
Subject
Space and Planetary Science,Astronomy and Astrophysics
Cited by
2 articles.
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