The statistical properties of stars at redshift, z=5, compared with the present epoch by Matthew R. Bate. on Tuesday 29 November

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 treat dust and gas temperatures separately

and include 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.

arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2211.15727v1