An aspherical distribution for the explosive burning ash of core-collapse supernovae

ABSTRACT It is widely believed that asphericity in the explosion is the crucial ingredient leading to successful core-collapse (CC) supernovae. However, direct observational evidence for the

explosion geometry and for the connection with the progenitor properties are still missing. Based on the thus-far largest late-phase spectroscopic sample of stripped-envelope CC supernovae,

we demonstrate that about half of the explosions exhibit a substantial deviation from sphericity. For these aspherical CC supernovae, the spatial distributions of the oxygen-burning ash and

the unburnt oxygen, as traced by the profiles of [Ca ii] λλ7291,7323 and [O i] λλ6300,6363 emissions, respectively, appear to be anticorrelated, which can be explained if the explosion is

bipolar and the oxygen-rich material burnt into two detached iron-rich bubbles. Our combined analysis of the explosion geometry and the progenitor mass further suggests that the degree of

asphericity grows with the mass of the carbon–oxygen core, which may be used to guide state-of-the-art simulations of CC supernova explosions. Access through your institution Buy or

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ORIGIN OF SUPERNOVA 2018ZD Article 28 June 2021 INFANT-PHASE REDDENING BY SURFACE FE-PEAK ELEMENTS IN A NORMAL TYPE IA SUPERNOVA Article 17 February 2022 MILLISECOND PULSARS FROM

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(https://www.wiserep.org/) and Supernova Database of Berkeley (http://heracles.astro.berkeley.edu/sndb/). The data that support the plots within this paper and other findings of this study

are available from the corresponding author upon reasonable request. CODE AVAILABILITY Astropy, Matplotlib, Numpy and Scipy are available from the Python Package Index (PyPI)

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Lett._ 658, L5–L8 (2007). Article  ADS  Google Scholar  Download references ACKNOWLEDGEMENTS We thank J. Jiang, S. Mattila and A. Jerkstrand for reviewing the presubmission manuscript and

providing a number of constructive suggestions. Q.F. acknowledges support from the Japan Society for the Promotion of Science (JSPS) through KAKENHI grant 20J23342. K.M. acknowledges support

from JSPS KAKENHI grants JP18H05223, JP20H00174 and JP20H04737. H.K. and T.N. are funded by the Research Council of Finland through projects 324504, 328898 and 353019. This work is

supported by the JSPS Open Partnership Bilateral Joint Research Projects between Japan and Finland (K.M. and H.K.; JPJSBP120229923). AUTHOR INFORMATION AUTHORS AND AFFILIATIONS * Department

of Astronomy, Kyoto University, Kyoto, Japan Qiliang Fang & Keiichi Maeda * Tuorla Observatory, Department of Physics and Astronomy, University of Turku, Turku, Finland Hanindyo

Kuncarayakti & Takashi Nagao * Finnish Centre for Astronomy with ESO (FINCA), University of Turku, Turku, Finland Hanindyo Kuncarayakti * Aalto University Metsähovi Radio Observatory,

Kylmälä, Finland Takashi Nagao * Aalto University Department of Electronics and Nanoengineering, AALTO, Espoo, Finland Takashi Nagao Authors * Qiliang Fang View author publications You can

also search for this author inPubMed Google Scholar * Keiichi Maeda View author publications You can also search for this author inPubMed Google Scholar * Hanindyo Kuncarayakti View author

publications You can also search for this author inPubMed Google Scholar * Takashi Nagao View author publications You can also search for this author inPubMed Google Scholar CONTRIBUTIONS

Q.F., K.M. and T.N. initialized the project. Q.F. led the nebular spectroscopy analysis, model construction and the manuscript preparation. K.M. organized the efforts to interpret the

results and assisted in manuscript preparation. H.K. and T.N. contributed to the spectroscopy analysis and interpretations. All authors contributed to the discussions and editing the

manuscript. CORRESPONDING AUTHORS Correspondence to Qiliang Fang or Keiichi Maeda. ETHICS DECLARATIONS COMPETING INTERESTS The authors declare no competing interests. PEER REVIEW PEER REVIEW

INFORMATION _Nature Astronomy_ thanks Vishnu Varma and the other, anonymous, reviewer(s) for their contribution to the peer review of this work. ADDITIONAL INFORMATION PUBLISHER’S NOTE

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applicable law. Reprints and permissions ABOUT THIS ARTICLE CITE THIS ARTICLE Fang, Q., Maeda, K., Kuncarayakti, H. _et al._ An aspherical distribution for the explosive burning ash of

core-collapse supernovae. _Nat Astron_ 8, 111–118 (2024). https://doi.org/10.1038/s41550-023-02120-8 Download citation * Received: 23 February 2023 * Accepted: 02 October 2023 * Published:

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