The electron-capture origin of supernova 2018zd

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,...

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Detalles Bibliográficos
Autores principales: Hiramatsu, Daichi, Howell, D. Andrew, Van Dyk, Schuyler D., Goldberg, Jared A., Maeda, Keiichi, Moriya, Takashi J., Tominaga, Nozomu, Nomoto, Ken’ichi, Hosseinzadeh, Griffin, Arcavi, Iair, McCully, Curtis, Burke, Jamison, Bostroem, K. Azalee, Valenti, Stefano, Dong, Yize, Brown, Peter J., Andrews, Jennifer E., Bilinski, Christopher, Williams, G. Grant, Smith, Paul S., Smith, Nathan, Sand, David J., Anand, Gagandeep S., Xu, Chengyuan, Filippenko, Alexei V., Bersten, Melina Cecilia, Folatelli, Gastón, Kelly, Patrick L., Noguchi, Toshihide, Itagaki, Koichi
Formato: Articulo Preprint
Lenguaje:Inglés
Publicado: 2021
Materias:
Ciencias Astronómicas
Stellar evolution
Physics
Supernova
Light curve
Stars
Solar mass
White dwarf
Nucleosynthesis
Astrophysics
Emission spectrum
Neutron star
Black hole
Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/126415
Aporte de:
SEDICI (UNLP) de Universidad Nacional de La Plata
Descripción
Sumario: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. Electron-capture supernovae are thought to come from progenitors with a narrow range of masses, and thus they are rare. Here the authors present six indicators of an electron-capture supernova origin, and find that supernova 2018zd fulfils all six criteria.

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