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High-entropy ejecta plumes in Cassiopeia A from neutrino-driven convection

Sato, Toshiki and Maeda, Keiichi and Nagataki, Shigehiro and Yoshida, Takashi and Grefenstette, Brian and Williams, Brian J. and Umeda, Hideyuki and Ono, Masaomi and Hughes, John P. (2021) High-entropy ejecta plumes in Cassiopeia A from neutrino-driven convection. Nature, 592 (7855). pp. 537-540. ISSN 0028-0836. doi:10.1038/s41586-021-03391-9. https://resolver.caltech.edu/CaltechAUTHORS:20210428-084643238

[img] PDF (Peer Review File) - Supplemental Material
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[img] Image (JPEG) (Extended Data Fig. 1: X-ray analysis for the southeastern Fe-rich region) - Supplemental Material
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[img] Image (JPEG) (Extended Data Fig. 2: X-ray spectral modelling around the Ti line) - Supplemental Material
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[img] Image (JPEG) (Extended Data Fig. 3: The Fe distribution (image) and the 44Ti upper limit map (coloured boxes) around the southeastern region) - Supplemental Material
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[img] Image (JPEG) (Extended Data Fig. 4: The one-dimensional core-collapse supernova nucleosynthesis model used in this study) - Supplemental Material
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[img] Image (JPEG) (Extended Data Fig. 5: Nucleosynthesis calculations in the peak temperature−density plane) - Supplemental Material
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[img] Image (JPEG) (Extended Data Fig. 6: The observed Ti/Fe and Cr/Fe mass ratios and nucleosynthesis models) - Supplemental Material
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[img] Image (JPEG) (Extended Data Fig. 7: The observed Ti/Fe and Mn/Fe mass ratios and nucleosynthesis models) - Supplemental Material
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[img] Image (JPEG) (Extended Data Fig. 8: Comparison between the Fe-rich and Si-rich regions) - Supplemental Material
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[img] Image (JPEG) (Extended Data Fig. 9: Comparisons of the observed Ni/Fe and Cr/Fe mass ratios in the Fe-rich ejecta region with those by theoretical calculations) - Supplemental Material
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[img] Image (JPEG) (Extended Data Fig. 10: Comparison of three Fe-rich regions in Cassiopeia A) - Supplemental Material
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Abstract

Recent multi-dimensional simulations suggest that high-entropy buoyant plumes help massive stars to explode. Outwardly protruding iron (Fe)-rich fingers of gas in the galactic supernova remnant Cassiopeia A seem to match this picture. Detecting the signatures of specific elements synthesized in the high-entropy nuclear burning regime (that is, α-rich freeze out) would constitute strong substantiating evidence. Here we report observations of such elements—stable titanium (Ti) and chromium (Cr)—at a confidence level greater than 5 standard deviations in the shocked high-velocity Fe-rich ejecta of Cassiopeia A. We found that the observed Ti/Fe and Cr/Fe mass ratios require α-rich freeze out, providing evidence of the existence of the high-entropy ejecta plumes that boosted the shock wave at explosion. The metal composition of the plumes agrees well with predictions for strongly neutrino-processed proton-rich ejecta. These results support the operation of the convective supernova engine via neutrino heating in the supernova that produced Cassiopeia A.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1038/s41586-021-03391-9DOIArticle
https://rdcu.be/cjBolPublisherFree ReadCube access
https://cxc.harvard.edu/cdaRelated ItemChandra Data Archive
https://heasarc.gsfc.nasa.gov/docs/nustar/nustar_archive.htmlRelated ItemNuSTAR Archive
https://cxc.cfa.harvard.edu/ciaoRelated ItemChandra Interactive Analysis of Observations: CIAO
http://www.atomdb.orgRelated ItematomDB
https://www.sron.nl/astrophysics-spexRelated ItemSPEX
https://heasarc.gsfc.nasa.gov/xanadu/xspecRelated ItemXspec
ORCID:
AuthorORCID
Sato, Toshiki0000-0001-9267-1693
Maeda, Keiichi0000-0003-2611-7269
Grefenstette, Brian0000-0002-1984-2932
Hughes, John P.0000-0002-8816-6800
Additional Information:© 2021 Nature Publishing Group. Received 15 July 2020; Accepted 24 February 2021; Published 21 April 2021. T.S. was supported by the Japan Society for the Promotion of Science (JSPS) KAKENHI grant number JP19K14739, the Special Postdoctoral Researchers Program, and FY 2019 Incentive Research Projects in RIKEN. K.M. was supported in part by Grants-in-Aid for the Scientific Research of JSPS (grant numbers JP18H05223 and JP20H00174). S.N. is partially supported by the Grants-in-Aid for the Scientific Research of JSPS (grant KAKENHI (A) 19H00693), the RIKEN programme for Evolution of Matter in the Universe (r-EMU), and the Theoretical and Mathematical Sciences Program of RIKEN (iTHEMS). J.PH. acknowledges support for X-ray studies of supernova remnants from NASA grant NNX15AK71G to Rutgers University. T.Y. is supported in part by a Grant-in-Aid for Scientific Research of Innovative Areas (JP20H05249). H.U. is supported in part by a Grant-in-Aid for Scientific Research (JP17H01130). Data availability: All the Chandra and NuSTAR data used in this research are available from the Chandra Data Archive (https://cxc.harvard.edu/cda/) and the NuSTAR Archive (https://heasarc.gsfc.nasa.gov/docs/nustar/nustar_archive.html) in raw and reduced formats. Code availability: To analyse X-ray data with Chandra, we used public software, Chandra Interactive Analysis of Observations: CIAO (https://cxc.cfa.harvard.edu/ciao/). We used public atomic data in atomDB (http://www.atomdb.org/) and SPEX (https://www.sron.nl/astrophysics-spex). We fitted the X-ray spectra with a public package, Xspec (https://heasarc.gsfc.nasa.gov/xanadu/xspec/). We have not made publicly available codes for the hydrodynamics and nucleosynthesis of supernova explosions because they are not prepared for open use. Instead, the simulated thermodynamic profiles of the supernova explosions and the composition distributions shown in this paper are available on request. Author Contributions: T.S. wrote the manuscript with comments from all the authors and analysed the Chandra data. K.M., S.N., H.U., J.P.H. and B.J.W. made important contributions to the overall science case and manuscript. B.G. analysed the NuSTAR data and made Fig. 1. T.Y., H.U. and M.O. calculated the nucleosynthesis models. The authors declare no competing interests. Peer review information: Nature thanks Patrick Young and the other, anonymous, reviewer(s) for their contribution to the peer review of this work. Peer reviewer reports are available.
Funders:
Funding AgencyGrant Number
Japan Society for the Promotion of Science (JSPS)JP19K14739
RIKENUNSPECIFIED
Japan Society for the Promotion of Science (JSPS)JP18H05223
Japan Society for the Promotion of Science (JSPS)JP20H00174
Japan Society for the Promotion of Science (JSPS)19H00693
NASANNX15AK71G
Japan Society for the Promotion of Science (JSPS)JP20H05249
Japan Society for the Promotion of Science (JSPS)JP17H01130
Subject Keywords:High-energy astrophysics; Stellar evolution
Issue or Number:7855
DOI:10.1038/s41586-021-03391-9
Record Number:CaltechAUTHORS:20210428-084643238
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20210428-084643238
Official Citation:Sato, T., Maeda, K., Nagataki, S. et al. High-entropy ejecta plumes in Cassiopeia A from neutrino-driven convection. Nature 592, 537–540 (2021). https://doi.org/10.1038/s41586-021-03391-9
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:108854
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:28 Apr 2021 16:52
Last Modified:28 Apr 2021 16:52

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