Type II Plateau supernovae as metallicity probes of the Universe
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We explore a method for metallicity determinations based on quantitative spectroscopy of Type II-Plateau supernovae (SNe II-P). For consistency, we first evolve a set of 15 M⊙ main-sequence stars at 0.1, 0.4, 1, and 2 times the solar metallicity. At the onset of core collapse, we trigger a piston-driven explosion and model the resulting ejecta and radiation. Our theoretical models of such red supergiant star explosions at different metallicity show that synthetic spectra of SNe II-P possess optical signatures during the recombination phase that are sensitive to metallicity variations. This sensitivity can be quantified and the metallicity inferred from the strengths of metal-line absorptions. Furthermore, these signatures are not limited to O, but also include Na, Ca, Sc, Ti, or Fe. When compared to a sample of SNe II-P from the Carnegie SN Project and previous SN followup programmes, we find that most events lie at a metallicity between 0.4 and 2 times solar, with a marked scarcity of SN II-P events at small magellanic cloud metallicity. This most likely reflects the paucity of low-metallicity star-forming regions in the local Universe. SNe II-P have high-plateau luminosities that make them observable spectroscopically at large distances. Because they exhibit signatures of diverse metal species, in the future they may offer a means to constrain the evolution of the composition (e.g. the O/Fe ratio) in the Universe out to a redshift of 1 and beyond. © 2014 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.
author list (cited authors)
Dessart, L., Gutierrez, C. P., Hamuy, M., Hillier, D. J., Lanz, T., Anderson, J. P., ... Suntzeff, N. B.