2003ApJ...594L.123L

We show that the ``puzzling'' chemical composition observed in the extremely metal-poor star HE 0107-5240 may be naturally explained by the concurrent pollution of at least two supernovae. In the simplest possible model, a supernova of quite low mass (∼15 M<sub>☉</sub>) underwent a ``normal'' explosion and ejected ∼0.06 M_☉of ⁵⁶Ni while a second one was massive enough (∼35 M_☉) to experience a strong fallback that locked in a compact remnant all the carbon-oxygen core. In a more general scenario, the pristine gas clouds were polluted by one or more supernovae of relatively low mass (less than ∼25 M_☉). The successive explosion of a quite massive star experiencing an extended fallback would have largely raised the abundances of the light elements in its close neighborhood.