Induced Formation of Primordial Low-Mass Stars

Astrophysics, abstract
astro-ph/0304074

From: Ruben Salvaterra <salvater@sissa.it>

Date: Thu, 3 Apr 2003 16:57:23 GMT   (44kb)

Authors:
R. Salvaterra,
A. Ferrara,
R. Schneider

Comments: 5 pages, 2 figures, MNRAS submitted

We show that the explosion of the first pair-unstable supernovae can trigger
low-mass star formation via gravitational fragmentation of the supernova-driven
gas shell. The necessary conditions for such instability are: (i) the mean
density of the ambient medium is 14 cm^{-3} < n_0 < 790 cm^{-3}; (ii) the
explosion energy E_SN > 3×10^{52} erg (i.e. core-collapse supernovae are not
suitable triggers). The typical mass of the unstable fragments is ~ 10^{5-6}
M_sun; their density is in the range 8×10^3 – 10^9 cm^{-3}. Fragments have a
metallicity strictly lower than 10^{-2.6} Z_sun and large values of the
gravitational-to-pressure force ratio f> 400. Based on these findings, we
conclude that the second generation of stars produced by such self-propagating
star formation is predominantly constituted by low-mass, long-living, extremely
metal-poor (or even metal-free, if mixing is suppressed) stars. We discuss the
implications of such results for Pop III star formation scenarios and for the
recently discovered most iron-poor halo star HE0107-5240.

References and citations for this submission:

SLAC-SPIRES HEP (refers to ,
cited by, arXiv reformatted)