Figure 1: Artist’s impression of a supernova.
A star's metallicity is basically a measure of the star's abundance of elements heavier than hydrogen and helium. J031300 is the most metal-poor star known to date. It also has an unusually low iron-to-hydrogen abundance ratio of only ~0.0000001. J031300 is suspected to have formed from the debris of the first supernovae explosions in the early universe. The first stars in the universe are comprised entirely of hydrogen and helium. These stars are known as Population III stars. They are predicted to be very massive and end their lives in supernovae explosions, seeding the early universe with the first nucleosynthetic yields of heavy elements.
The most metal-poor stars known in the present universe might be the direct descendents of Population III stars. Simulations performed by Chen et al. (2016) of supernovae explosions of Population III stars with 12 and 60 times the mass of the Sun indicate that they produce nucleosynthetic elemental yields that fit quite well with the abundance of metals measured for J031300. Furthermore, the simulations suggest that the fall back of iron-group elements into the newly formed black hole or neutron star following a supernova explosion can explain the remarkably low iron-to-hydrogen abundance ratio of J031300. More observations of such extremely metal-poor stars in the present universe might shed light on the properties of the first stars in the universe.
Figure 2: Simulated nucleosynthetic elemental yields for supernovae explosions of Population III stars with 12 (Z12) and 60 (Z60) times the mass of the Sun in comparison with the abundance of metals measured for J031300. Chen et al. (2016)
Chen et al. (2016), “Low Energy Population III Supernovae and the Origin of the Extremely Metal-Poor Star SMSS J031300.36-670839.3”, arXiv:1601.06896 [astro-ph.HE]