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タイトル: | SN 2020uem: a Possible Thermonuclear Explosion within a Dense Circumstellar Medium (II). The Properties of the CSM from Polarimetry and Light-curve Modeling |
著者: | Uno, Kohki Nagao, Takashi Maeda, Keiichi Kuncarayakti, Hanindyo Tanaka, Masaomi Kawabata, Koji S. Nakaoka, Tatsuya Kawabata, Miho Yamanaka, Masayuki Aoki, Kentaro Isogai, Keisuke Ogawa, Mao Tajitsu, Akito Imazawa, Ryo |
著者名の別形: | 宇野, 孔起 前田, 啓一 川端, 美穂 山中, 雅之 磯貝, 桂介 小川, 真央 |
キーワード: | Supernovae Supernova dynamics Circumstellar matter Polarimetry Spectropolarimetry |
発行日: | 20-Feb-2023 |
出版者: | American Astronomical Society |
誌名: | The Astrophysical Journal |
巻: | 944 |
号: | 2 |
論文番号: | 204 |
抄録: | Type IIn/Ia-CSM supernovae (SNe IIn/Ia-CSM) are classified by their characteristic spectra, which exhibit narrow hydrogen emission lines originating from strong interaction with a circumstellar medium (CSM) together with broad lines of intermediate-mass elements. We performed intensive follow-up observations of SN IIn/Ia-CSM 2020uem, including photometry, spectroscopy, and polarimetry. In this paper, we focus on the results of polarimetry. We performed imaging polarimetry at 66 days and spectropolarimetry at 103 days after discovery. SN 2020uem shows a high continuum polarization of 1.0%–1.5% without wavelength dependence. Besides, the polarization degree and position angle keep roughly constant. These results suggest that SN 2020uem is powered by strong interaction with a confined and aspherical CSM. We performed simple polarization modeling, based on which we suggest that SN 2020uem has an equatorial-disk/torus CSM. Besides, we performed semi-analytic light-curve modeling and estimated the CSM mass. We revealed that the mass-loss rate in the final few hundred years immediately before the explosion of SN 2020uem is in the range of 0.01–0.05 M⊙ yr⁻¹, and that the total CSM mass is 0.5–4 M⊙. The CSM mass can be accommodated by not only a red supergiant (RSG), but also by a red giant (RG) or an asymptotic giant branch (AGB) star. As a possible progenitor scenario of SN 2020uem, we propose a white dwarf binary system including an RG, RSG, or AGB star, especially a merger scenario via common envelope evolution, i.e., the core-degenerate scenario or a variant. |
著作権等: | © 2023. The Author(s). Published by the American Astronomical Society. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. |
URI: | http://hdl.handle.net/2433/281946 |
DOI(出版社版): | 10.3847/1538-4357/acb5eb |
出現コレクション: | 学術雑誌掲載論文等 |
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