2006/12/05 by Evan Scannapieco, Daisuke Kawata, Chris B. Brook +4 · 1 citation
Physics and Astronomy · #Astronomy #Astronomy and Astrophysical Research #Astrophysics #Galactic halo #Galaxies: Formation, Evolution, Phenomena #Galaxy #Halo #Initial mass function #Milky Way #Physics #Star formation #Stars #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1086/508487
published as Astrophys.J.653:285-299,2006 · 17 Pages, ApJ, in Press. Higher resolution version available here: http://www.ociw.edu/~dkawata/for/evan/draft/final/ms.pdf
openalex publication_date 2006/12/05 · arxiv created 2006/12/06 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We study the spatial distribution of Galactic metal-free stars by combining an extremely high-resolution (7.8 × 10 5 M ☉ per particle) cold dark matter N -body simulation of the Milky Way with a semianalytic model of metal enrichment. This approach allows us to resolve halos with virial temperatures down to the 10 4 K atomic cooling limit, and it is sufficiently flexible to make a number of robust conclusions, despite the extremely uncertain properties of the first stars. Galactic metal-free stars are formed over a large redshift range, which peaks at z ≈ 10, but continues down to z ≈ 5, contributing stars at a wide range of Galactocentric radii. Stars containing only metals from primordial stars are similarly widespread. Neither changing the efficiency of metal dispersal by 2 orders of magnitude, nor drastically changing the approximations in our semianalytical model can affect these result. Thus, if they have sufficiently long lifetimes, a significant number of stars formed in initially primordial star clusters should be found in the nearby Galactic halo. Observations of metal abundances in Galactic halo stars should be taken as directly constraining the properties of primordial stars, and the lack of metal-free halo stars today should be taken as strongly suggesting a 0.8 M ☉ lower limit on the primordial initial mass function.