SN 2016dsg: A thermonuclear explosion involving a thick helium shell

Dong, Yize, Valenti, Stefano, Polin, Abigail, Boyle, Aoife, Flörs, Andreas, Vogl, Christian, Kerzendorf, Wolfgang E., Sand, David J., Jha, Saurabh W., Wyrzykowski, Łukasz, Bostroem, K. Azalee, Pearson, Jeniveve, McCully, Curtis, Andrews, Jennifer E., Benetti, Stefano, Blondin, Stéphane, Galbany, L., Gromadzki, Mariusz, Hosseinzadeh, Griffin, Howell, D. Andrew, Inserra, Cosimo ORCID: https://orcid.org/0000-0002-3968-4409, Jencson, Jacob E., Lundquist, Michael, Lyman, J. D., Magee, Mark, Maguire, Kate, Meza, Nicolas, Srivastav, Shubham, Taubenberger, Stefan, Terwel, J. H., Wyatt, Samuel and Young, D. R. 2022. SN 2016dsg: A thermonuclear explosion involving a thick helium shell. Astrophysical Journal 934 (2) , 102. 10.3847/1538-4357/ac75eb

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Abstract

Abstract: A thermonuclear explosion triggered by a He-shell detonation on a carbon–oxygen white-dwarf core has been predicted to have strong UV line blanketing at early times due to the iron-group elements produced during He-shell burning. We present the photometric and spectroscopic observations of SN 2016dsg, a subluminous peculiar Type I supernova consistent with a thermonuclear explosion involving a thick He shell. With a redshift of 0.04, the i-band peak absolute magnitude is derived to be around −17.5. The object is located far away from its host, an early-type galaxy, suggesting it originated from an old stellar population. The spectra collected after the peak are unusually red, show strong UV line blanketing and weak O i λ7773 absorption lines, and do not evolve significantly over 30 days. An absorption line around 9700–10500 Å is detected in the near-infrared spectrum and is likely from the unburnt He in the ejecta. The spectroscopic evolution is consistent with the thermonuclear explosion models for a sub-Chandrasekhar-mass white dwarf with a thick He shell, while the photometric evolution is not well described by existing models.

Item Type:	Article
Date Type:	Published Online
Status:	Published
Schools:	Physics and Astronomy
Additional Information:	License information from Publisher: LICENSE 1: URL: http://creativecommons.org/licenses/by/4.0/, Type: cc-by
Publisher:	American Astronomical Society
ISSN:	0004-637X
Date of First Compliant Deposit:	29 July 2022
Date of Acceptance:	31 May 2022
Last Modified:	14 May 2023 04:24
URI:	https://orca.cardiff.ac.uk/id/eprint/151548

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