Detecting primordial stars

If metal-free stars have masses 140M⊙ ≲ M* ≲ 260M⊙, they are expected to end their lives as pair-production supernovae (PPSNe), in which an electron-positron pair-production instability triggers explosive nuclear burning. Using the implicit hydrodynamics code KEPLER, we calculate a set of PPSNe light curves that allows us to assess observational strategies for finding these objects. The peak luminosities of typical PPSNe are only slightly greater than those of Type Ia supernovae, but they remain bright much longer (∼1 year) and have hydrogen lines. Ongoing supernova searches may soon be able to place stringent limits on the fraction of very massive stars out to z ≈ 2. The planned Joint Dark Energy Mission satellite will be able to extend these limits out to z ≈ 6.