Open AccessProbing the formation of the first low‐mass stars with stellar archaeology
Author(s) -
Frebel Anna,
Johnson Jarrett L.,
Bromm Volker
Publication year - 2007
Publication title -
monthly notices of the royal astronomical society: letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.067
H-Index - 122
eISSN - 1745-3933
pISSN - 1745-3925
DOI - 10.1111/j.1745-3933.2007.00344.x
Subject(s) - globular cluster , physics , stars , astrophysics , initial mass function , galaxy , population , astronomy , star formation , galactic halo , star cluster , halo , demography , sociology
We investigate the conditions under which the first low‐mass stars formed in the Universe by confronting theoretical predictions governing the transition from massive Population III to low‐mass Population II stars with recent observational C and/or O abundance data of metal‐poor Galactic stars. We introduce a new ‘observer‐friendly’ function, the transition discriminant D trans , which provides empirical constraints as well as a powerful comparison between the currently available data of metal‐poor halo stars and theoretical predictions of the formation of the first low‐mass stars (≲ 1 M ⊙ ) . Specifically, we compare the empirical stellar results with the theory that fine‐structure lines of C and O dominate the transition from Population III to Population II in the early Universe. We find the currently available data for halo stars as well as for dwarf spheroidal (dSph) galaxies and globular clusters to be consistent with this theory. An explanation for the observed lack of metal‐poor stars in dSph galaxies and globular clusters is also suggested. Finally, we predict that any star to be found with [Fe/H]≲−4 should have enhanced C and/or O abundances. The high C and O abundances of the two most iron‐poor stars are in line with our prediction.