Low-energy Population III supernovae and the origin of extremely
  metal-poor stars
  Some ancient, dim, metal-poor stars may have formed in the ashes of the first
supernovae (SNe). If their chemical abundances can be reconciled with the
elemental yields of specific Population III (Pop III) explosions, they could
reveal the properties of primordial stars. But multidimensional simulations of
such explosions are required to predict their yields because dynamical
instabilities can dredge material up from deep in the ejecta that would
otherwise be predicted to fall back on to the central remnant and be lost in
one-dimensional (1D) models. We have performed two-dimensional (2D) numerical
simulations of two low-energy Pop III SNe, a 12.4 Msun explosion and a 60 Msun
explosion, and find that they produce elemental yields that are a good fit to
those measured in the most iron-poor star discovered to date, SMSS
J031300.36-670839.3 (J031300). Fallback on to the compact remnant in these weak
explosions accounts for the lack of measurable iron in J031300 and its low
iron-group abundances in general. Our 2D explosions produce higher abundances
of heavy elements (atomic number Z > 20) than their 1D counterparts due to
dredge-up by fluid instabilities. Since almost no Ni is ejected by these weak
SNe, their low luminosities will prevent their detection in the near-infrared
with the James Webb Space Telescope and future 30-m telescopes on the ground.
The only evidence that they ever occurred will be in the fossil abundance
record.
