TY - JOUR
T1 - The electron-capture origin of supernova 2018zd
AU - Hiramatsu, Daichi
AU - Howell, D. Andrew
AU - Van Dyk, Schuyler D.
AU - Goldberg, Jared A.
AU - Maeda, Keiichi
AU - Moriya, Takashi J.
AU - Tominaga, Nozomu
AU - Nomoto, Ken’ichi
AU - Hosseinzadeh, Griffin
AU - Arcavi, Iair
AU - McCully, Curtis
AU - Burke, Jamison
AU - Bostroem, K. Azalee
AU - Valenti, Stefano
AU - Dong, Yize
AU - Brown, Peter J.
AU - Andrews, Jennifer E.
AU - Bilinski, Christopher
AU - Williams, G. Grant
AU - Smith, Paul S.
AU - Smith, Nathan
AU - Sand, David J.
AU - Anand, Gagandeep S.
AU - Xu, Chengyuan
AU - Filippenko, Alexei V.
AU - Bersten, Melina C.
AU - Folatelli, Gastón
AU - Kelly, Patrick L.
AU - Noguchi, Toshihide
AU - Itagaki, Koichi
N1 - Publisher Copyright:
© 2021, The Author(s), under exclusive licence to Springer Nature Limited.
PY - 2021/9
Y1 - 2021/9
N2 - In the transitional mass range (~8–10 solar masses) between white dwarf formation and iron core-collapse supernovae, stars are expected to produce an electron-capture supernova. Theoretically, these progenitors are thought to be super-asymptotic giant branch stars with a degenerate O + Ne + Mg core, and electron capture onto Ne and Mg nuclei should initiate core collapse1–4. However, no supernovae have unequivocally been identified from an electron-capture origin, partly because of uncertainty in theoretical predictions. Here we present six indicators of electron-capture supernovae and show that supernova 2018zd is the only known supernova with strong evidence for or consistent with all six: progenitor identification, circumstellar material, chemical composition5–7, explosion energy, light curve and nucleosynthesis8–12. For supernova 2018zd, we infer a super-asymptotic giant branch progenitor based on the faint candidate in the pre-explosion images and the chemically enriched circumstellar material revealed by the early ultraviolet colours and flash spectroscopy. The light-curve morphology and nebular emission lines can be explained by the low explosion energy and neutron-rich nucleosynthesis produced in an electron-capture supernova. This identification provides insights into the complex stellar evolution, supernova physics, cosmic nucleosynthesis and remnant populations in the transitional mass range.
AB - In the transitional mass range (~8–10 solar masses) between white dwarf formation and iron core-collapse supernovae, stars are expected to produce an electron-capture supernova. Theoretically, these progenitors are thought to be super-asymptotic giant branch stars with a degenerate O + Ne + Mg core, and electron capture onto Ne and Mg nuclei should initiate core collapse1–4. However, no supernovae have unequivocally been identified from an electron-capture origin, partly because of uncertainty in theoretical predictions. Here we present six indicators of electron-capture supernovae and show that supernova 2018zd is the only known supernova with strong evidence for or consistent with all six: progenitor identification, circumstellar material, chemical composition5–7, explosion energy, light curve and nucleosynthesis8–12. For supernova 2018zd, we infer a super-asymptotic giant branch progenitor based on the faint candidate in the pre-explosion images and the chemically enriched circumstellar material revealed by the early ultraviolet colours and flash spectroscopy. The light-curve morphology and nebular emission lines can be explained by the low explosion energy and neutron-rich nucleosynthesis produced in an electron-capture supernova. This identification provides insights into the complex stellar evolution, supernova physics, cosmic nucleosynthesis and remnant populations in the transitional mass range.
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U2 - 10.1038/s41550-021-01384-2
DO - 10.1038/s41550-021-01384-2
M3 - Article
AN - SCOPUS:85115451852
SN - 2397-3366
VL - 5
SP - 903
EP - 910
JO - Nature Astronomy
JF - Nature Astronomy
IS - 9
ER -