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A WC/WO star exploding within an expanding carbon–oxygen–neon nebula

Gal-Yam, A. and Bruch, R. and Schulze, S. and Yang, Y. and Perley, D. A. and Irani, I. and Sollerman, J. and Kool, E. C. and Soumagnac, M. T. and Yaron, O. and Strotjohann, N. L. and Zimmerman, E. and Barbarino, C. and Kulkarni, S. R. and Kasliwal, M. M. and De, K. and Yao, Y. and Fremling, C. and Yan, L. and Ofek, E. O. and Fransson, C. and Filippenko, A. V. and Zheng, W. and Brink, T. G. and Copperwheat, C. M. and Foley, R. J. and Brown, J. and Siebert, M. and Leloudas, G. and Cabrera Lavers, A. L. and Garcia Alvarez, D. and Marante-Barreto, A. and Frederick, S. and Hung, T. and Wheeler, J. C. and Vinkó, J. and Thomas, B. P. and Graham, M. J. and Duev, D. A. and Drake, A. J. and Dekany, R. and Bellm, E. C. and Rusholme, B. and Shupe, D. L. and Andreoni, I. and Sharma, Y. and Riddle, R. and van Roestel, J. and Knezevic, N. (2022) A WC/WO star exploding within an expanding carbon–oxygen–neon nebula. Nature, 601 (7892). pp. 201-204. ISSN 0028-0836. doi:10.1038/s41586-021-04155-1.

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[img] PDF (Supplementary Figs 1–5 and Supplementary Tables 1–3) - Supplemental Material
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[img] Image (JPEG) (Extended Data Fig. 1: Early spectroscopy shows strong emission lines of carbon, oxygen and neon) - Supplemental Material
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[img] Image (JPEG) (Extended Data Fig. 2: Evolution toward lower ionization) - Supplemental Material
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[img] Image (JPEG) (Extended Data Fig. 3: Development of the photospheric spectrum) - Supplemental Material
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[img] Image (JPEG) (Extended Data Fig. 4: Blackbody SED fits calculated using PhotoFitic spectrum) - Supplemental Material
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[img] Image (JPEG) (Extended Data Fig. 5: Light curves of SN 2019hgp extending from the UV to the NIR) - Supplemental Material
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[img] Image (JPEG) (Extended Data Fig. 6: Low-order polynomial fits to the early r-band photometry indicate that the explosion occurred on 2019 June 7.1 ± 0.2 d) - Supplemental Material
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[img] Image (JPEG) (Extended Data Fig. 7: A comparison of spectra of interacting SNe) - Supplemental Material
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[img] Image (JPEG) (Extended Data Fig. 8: SN 2019hgp (marked by the crosshair) exploded in the outskirts of its host galaxy at a projected distance of 4.4 kpc (3.54″)) - Supplemental Material
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[img] Image (JPEG) (Extended Data Fig. 9: Extinction fits to our first-epoch SED (+1.5 d) using various extinction laws) - Supplemental Material
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[img] Image (JPEG) (Extended Data Fig. 10: Modelling of the emission complex around 4,660Å during the first two Gemini epochs) - Supplemental Material
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[img] Image (JPEG) (Extended Data Fig. 11: A comparison of our +27.4 d Keck spectrum of SN 2019hgp to SYNOW models) - Supplemental Material
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The final fate of massive stars, and the nature of the compact remnants they leave behind (black holes and neutron stars), are open questions in astrophysics. Many massive stars are stripped of their outer hydrogen envelopes as they evolve. Such Wolf–Rayet stars emit strong and rapidly expanding winds with speeds greater than 1,000 kilometres per second. A fraction of this population is also helium-depleted, with spectra dominated by highly ionized emission lines of carbon and oxygen (types WC/WO). Evidence indicates that the most commonly observed supernova explosions that lack hydrogen and helium (types Ib/Ic) cannot result from massive WC/WO stars , leading some to suggest that most such stars collapse directly into black holes without a visible supernova explosion4. Here we report observations of SN 2019hgp, beginning about a day after the explosion. Its short rise time and rapid decline place it among an emerging population of rapidly evolving transients. Spectroscopy reveals a rich set of emission lines indicating that the explosion occurred within a nebula composed of carbon, oxygen and neon. Narrow absorption features show that this material is expanding at high velocities (greater than 1,500 kilometres per second), requiring a compact progenitor. Our observations are consistent with an explosion of a massive WC/WO star, and suggest that massive Wolf–Rayet stars may be the progenitors of some rapidly evolving transients.

Item Type:Article
Related URLs:
URLURL TypeDescription ReadCube access Paper ItemWISeREP
Gal-Yam, A.0000-0002-3653-5598
Bruch, R.0000-0001-8208-2473
Schulze, S.0000-0001-6797-1889
Perley, D. A.0000-0001-8472-1996
Irani, I.0000-0002-7996-8780
Sollerman, J.0000-0003-1546-6615
Kool, E. C.0000-0002-7252-3877
Soumagnac, M. T.0000-0001-6753-1488
Yaron, O.0000-0002-0301-8017
Strotjohann, N. L.0000-0002-4667-6730
Zimmerman, E.0000-0001-8985-2493
Barbarino, C.0000-0002-3821-6144
Kulkarni, S. R.0000-0001-5390-8563
Kasliwal, M. M.0000-0002-5619-4938
De, K.0000-0002-8989-0542
Yao, Y.0000-0001-6747-8509
Fremling, C.0000-0002-4223-103X
Yan, L.0000-0003-1710-9339
Ofek, E. O.0000-0002-6786-8774
Fransson, C.0000-0001-8532-3594
Filippenko, A. V.0000-0003-3460-0103
Brink, T. G.0000-0001-5955-2502
Copperwheat, C. M.0000-0001-7983-8698
Brown, J.0000-0002-1885-6419
Siebert, M.0000-0003-2445-3891
Leloudas, G.0000-0002-8597-0756
Cabrera Lavers, A. L.0000-0002-9153-8724
Frederick, S.0000-0001-9676-730X
Hung, T.0000-0002-9878-7889
Wheeler, J. C.0000-0003-1349-6538
Vinkó, J.0000-0001-8764-7832
Graham, M. J.0000-0002-3168-0139
Duev, D. A.0000-0001-5060-8733
Dekany, R.0000-0002-5884-7867
Bellm, E. C.0000-0001-8018-5348
Rusholme, B.0000-0001-7648-4142
Shupe, D. L.0000-0003-4401-0430
Andreoni, I.0000-0002-8977-1498
Sharma, Y.0000-0003-4531-1745
Riddle, R.0000-0002-0387-370X
van Roestel, J.0000-0002-2626-2872
Additional Information:© 2022 Nature Publishing Group. Received 06 April 2021; Accepted 15 October 2021; Published 12 January 2022. This work is based on observations obtained with the Samuel Oschin 48-inch Telescope and the 60-inch Telescope at Palomar Observatory as part of the Zwicky Transient Facility project. ZTF is supported by the US National Science Foundation (NSF) under grant AST-1440341 and a collaboration including Caltech, IPAC, the Weizmann Institute for Science, the Oskar Klein Center at Stockholm University, the University of Maryland, the University of Washington, Deutsches Elektronen-Synchrotron and Humboldt University, Los Alamos National Laboratories, the TANGO Consortium of Taiwan, the University of Wisconsin at Milwaukee, and Lawrence Berkeley National Laboratories. Operations are conducted by COO, IPAC, and UW. This work includes observations made with the Nordic Optical Telescope (NOT), owned in collaboration by the University of Turku and Aarhus University, and operated jointly by Aarhus University, the University of Turku and the University of Oslo (representing Denmark, Finland and Norway, respectively), the University of Iceland and Stockholm University, at the Observatorio del Roque de los Muchachos, La Palma, Spain, of the Instituto de Astrofísica de Canarias. These data were obtained with ALFOSC, which is provided by the Instituto de Astrofísica de Andalucía (IAA) under a joint agreement with the University of Copenhagen and NOT. This work includes observations made with the GTC telescope, in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias, under Director’s Discretionary Time. Some of the data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration (NASA); the Observatory was made possible by the generous financial support of the W. M. Keck Foundation. This work includes observations obtained at the international Gemini Observatory, a programme of NSF’s NOIRLab, which is managed by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with the NSF on behalf of the Gemini Observatory partnership: the NSF (USA), National Research Council (Canada), Agencia Nacional de Investigación y Desarrollo (Chile), Ministerio de Ciencia, Tecnología e Innovacíon (Argentina), Ministério da Ciência, Tecnologia, Inovações e Comunicações (Brazil), and Korea Astronomy and Space Science Institute (Republic of Korea). We wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Maunakea has always had within the Indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain. This work includes observations obtained at the Liverpool Telescope, which is operated on the island of La Palma by Liverpool John Moores University in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias with financial support from the UK Science and Technology Facilities Council. Research at Lick Observatory is partially supported by a generous gift from Google. This work includes observations obtained with the Hobby–Eberly Telescope, which is a joint project of the University of Texas at Austin, the Pennsylvania State University, Ludwig-Maximilians-Universität München, and Georg-August-Universität Göttingen. These results made use of the Lowell Discovery Telescope (LDT) at Lowell Observatory. Lowell is a private, non-profit institution dedicated to astrophysical research and public appreciation of astronomy and operates the LDT in partnership with Boston University, the University of Maryland, the University of Toledo, Northern Arizona University and Yale University. This work benefited from the OPTICON telescope access programme (, funded from the European Union’s Horizon 2020 research and innovation programme under grant agreement 730890. We made use of IRAF, which is distributed by the NSF NOIRLab. A.G.-Y. is supported by the EU via ERC grant no. 725161, the ISF GW excellence centre, an IMOS space infrastructure grant, BSF/Transformative and GIF grants, as well as by the Benoziyo Endowment Fund for the Advancement of Science, the Deloro Institute for Advanced Research in Space and Optics, The Veronika A. Rabl Physics Discretionary Fund, Minerva, Yeda-Sela and the Schwartz/Reisman Collaborative Science Program; A.G.-Y. is the incumbent of the The Arlyn Imberman Professorial Chair. M.M.K. acknowledges generous support from the David and Lucile Packard Foundation; the GROWTH project was funded by the NSF under grant AST-1545949. E.C.K., J.S. and S.S. acknowledge support from the G.R.E.A.T. research environment funded by Vetenskapsrå det, the Swedish Research Council, under project number 2016-06012; E.C.K. also received support from The Wenner-Gren Foundations. The Oskar Klein Center’s participation in ZTF was made available by the K.A.W. Foundation. G.L. is supported by a research grant (19054) from VILLUM FONDEN. J.C.W. and B.P.T. are supported by NSF grant AST-1813825. A.V.F.’s supernova group at UC Berkeley is supported by the TABASGo Foundation, the Christopher R. Redlich Fund, and the Miller Institute for Basic Research in Science (A.V.F. is a Senior Miller Fellow). Data availability: The photometry of SN 2019hgp is available in Supplementary Table 1, and all the observations (photometry and spectra) are available from WISeREP52 ( Matlab scripts that generate most of the plots within this paper are available from the corresponding author upon request. Opticon observations were obtained under programme ID OPT/2019A/024, PI A.G.-Y. Code availability: Relevant software sources have been provided in the text, web locations provided as references, and are publicly available. Author Contributions: A.G.-Y. initiated the project, planned the observations, conducted spectroscopic and physical analysis, and wrote the manuscript. R.B. identified the transient, initiated follow-up observations, conducted photometric analysis, and contributed to the WIS infant SN programme. S.S. contributed to follow-up design and execution, conducted multiwavelength and host-galaxy analysis, and contributed to the manuscript. Y. Yang. contributed to follow-up design and execution, reduced the Gemini spectra, and contributed to the manuscript. D.A.P. conducted follow-up observations with the LT and contributed to the manuscript. I.I. conducted photometric and spectroscopic analysis and contributed to physical interpretation and manuscript writing. J.S. helped to plan and develop the manuscript and provided NOT data. E.C.K. analysed the bolometric light curve and provided physical modelling. M.T.S. contributed to photometric analysis. O.Y. conducted spectroscopic modelling. N.L.S. conducted a prediscovery variability search and contributed to the manuscript. E.Z. contributed to spectroscopic analysis. C.B. provided the sample of SNe Ic from PTF and reduced the NOT spectroscopy. S.R.K. is the ZTF PI. S.R.K., M.M.K., C. Fremling. and L.Y. provided Palomar and Keck data. K.D. and Y. Yao. reduced the Palomar and Keck data. E.O.O. and C. Fransson. contributed to physical interpretation. A.V.F., W.Z., T.G.B., R.J.F., J.B. and M.S. contributed Lick and Keck data; A.V.F. also contributed to the manuscript. C.M.C. contributed LT data. A.L.C.-L., D.G.-A. and A.M.-B. provided GTC observations. S.F. and T.H. provided LDT observations. J.C.W., B.P.T. and J.V. planned, obtained and reduced the HET observations. G.L. reduced the GTC spectra and contributed to the manuscript. M.J.G., D.A.D., A.J.D., R.D., E.C.B., B.R., D.L.S., I.A., Y.S., R.R. and J.v.R. are ZTF builders. N.K. contributed to the spectroscopic analysis. Many authors provided comments on the manuscript, and all authors have approved it. The authors declare no competing interests. Nature thanks the anonymous reviewers for their contribution to the peer review of this work.
Group:Astronomy Department, Infrared Processing and Analysis Center (IPAC), Zwicky Transient Facility
Funding AgencyGrant Number
ZTF partner institutionsUNSPECIFIED
W. M. Keck FoundationUNSPECIFIED
Gemini PartnershipUNSPECIFIED
Science and Technology Facilities Council (STFC)UNSPECIFIED
European Research Council (ERC)730890
European Research Council (ERC)725161
Israel Science FoundationUNSPECIFIED
Ministry of Science (Israel)UNSPECIFIED
Binational Science Foundation (USA-Israel)UNSPECIFIED
German-Israeli Foundation for Research and DevelopmentUNSPECIFIED
Benoziyo Endowment Fund for the Advancement of ScienceUNSPECIFIED
Deloro Institute for Advanced Research in Space and OpticsUNSPECIFIED
Veronika A. Rabl Physics Discretionary FundUNSPECIFIED
Schwartz/Reisman Collaborative Science ProgramUNSPECIFIED
Arlyn Imberman Professorial ChairUNSPECIFIED
David and Lucile Packard FoundationUNSPECIFIED
Swedish Research Council2016-06012
Wenner-Gren FoundationUNSPECIFIED
Knut and Alice Wallenberg FoundationUNSPECIFIED
Christopher R. Redlich FundUNSPECIFIED
Miller Institute for Basic Research in ScienceUNSPECIFIED
Subject Keywords:Time-domain astronomy; Transient astrophysical phenomena
Issue or Number:7892
Record Number:CaltechAUTHORS:20210927-205831656
Persistent URL:
Official Citation:Gal-Yam, A., Bruch, R., Schulze, S. et al. A WC/WO star exploding within an expanding carbon–oxygen–neon nebula. Nature 601, 201–204 (2022).
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:111051
Deposited By: George Porter
Deposited On:29 Nov 2021 23:35
Last Modified:12 Jan 2022 23:43

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