The lowest-metallicity type II supernova from the highest-mass red supergiant progenitor

J. Anderson , Luc Dessart (1) , C. P. Gutiérrez (2) , T. Krühler , L. Galbany , A. Jerkstrand , S. Smartt , C. Contreras , N. Morrell , M. Phillips , M. Stritzinger , E. Hsiao , S. González-Gaitán , C. Agliozzo , S. Castellón , K. Chambers , T. -W. Chen , H. Flewelling , C. González , G. Hosseinzadeh , M. Huber , M. Fraser , C. Inserra (2) , E. Kankare (3) , S. Mattila , E. Magnier (4) , K. Maguire , T. Lowe , J. Sollerman (5) , M. Sullivan (2) , D. Young , S. Valenti

1 LFCA - Laboratoire Franco-Chilien d'Astronomie
2 University of Southampton
3 ARC - Astrophysics Research Centre [Belfast]
4 UH - University of Hawai'i [Honolulu]
5 Oskar Klein Centre [Stockholm]

Red supergiants have been confirmed as the progenitor stars of the majority of hydrogen-rich type II supernovae1. However, while such stars are observed with masses >25 M⊙ (ref. 2), detections of >18 M⊙ progenitors remain elusive1. Red supergiants are also expected to form at all metallicities, but discoveries of explosions from low-metallicity progenitors are scarce. Here, we report observations of the type II supernova, SN 2015bs, for which we infer a progenitor metallicity of ≤0.1 Z⊙ from comparison to photospheric-phase spectral models3, and a zero-age main-sequence mass of 17–25 M⊙ through comparison to nebular-phase spectral models4,5. SN 2015bs displays a normal ‘plateau’ light-curve morphology, and typical spectral properties, implying a red supergiant progenitor. This is the first example of such a high-mass progenitor for a ‘normal’ type II supernova, suggesting a link between high-mass red supergiant explosions and low-metallicity progenitors.

Domaines: Astrophysique stellaire et solaire [astro-ph.SR]

J. Anderson, Luc Dessart, C. P. Gutiérrez, T. Krühler, L. Galbany, et al.. The lowest-metallicity type II supernova from the highest-mass red supergiant progenitor. Nature Astronomy, 2018, 2 (7), pp.574-579. ⟨10.1038/s41550-018-0458-4⟩. ⟨hal-02351317⟩