Peculiar Spectral Evolution of the Type I Supernova 2019eix: A Possible Double Detonation from a Helium Shell on a Sub-Chandrasekhar-mass White Dwarf
Peculiar Spectral Evolution of the Type I Supernova 2019eix: A Possible Double Detonation from a Helium Shell on a Sub-Chandrasekhar-mass White Dwarf
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DOI：
10.3847/1538-4357/acdd6a
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发表时间：
2023-05
期刊：
影响因子：
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通讯作者：
E. P. Gonzalez;D. Howell;J. Burke;Yize Dong;D. Hiramatsu;C.McCully;C.Pellegrino;W. E. Kerzendorf;M. Modjaz;G. Terreran;M. Williamson
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作者：
E. P. Gonzalez;D. Howell;J. Burke;Yize Dong;D. Hiramatsu;C.McCully;C.Pellegrino;W. E. Kerzendorf;M. Modjaz;G. Terreran;M. Williamson
我们提供了附近I型超新星（SN Ia）2019eix（最初被归类为SN Ic）的光度和光谱数据，从发现之日到最大亮度后的100天。在最大亮度之前，SN 2019eix类似于典型的SN Ic，尽管缺乏通常的O i功能。它的光变曲线类似于典型的超新星Ic，衰减率（ΔM 15，V = 0.84），绝对星等MV = −18.35。然而，在最大光之后，该SN具有不寻常的光谱特征，大程度的线混合，蓝色中的显著线覆盖（λ < 5000 λ），以及在峰值亮度期间和之后的强Ca ii吸收特征。这些不寻常的光谱特征类似于亚发光热核爆炸的模型，特别是Ia超新星的双爆轰模型。在光度上，SN 2019eix似乎比其他双爆候选者更亮，衰减速度更慢。我们使用辐射转移代码TARDIS以SN 1994I（SN Ic）作为基础模型来模拟光谱，看看我们是否可以重现SN 2019eix的不寻常特征，并发现它们与O i特征的例外是一致的。我们还将SN 2019eix与双爆轰模型进行了比较，发现它们与SN 2019eix的观测结果最匹配，但未能再现其完整的光度和光谱演化。
We present photometric and spectroscopic data for the nearby Type I supernova (SN Ia) 2019eix (originally classified as an SN Ic), from the day of its discovery up to 100 days after maximum brightness. Before maximum light, SN 2019eix resembles a typical SN Ic, albeit lacking the usual O i feature. Its light curve is similar to the typical SN Ic with decline rates (ΔM 15,V = 0.84) and absolute magnitude M V = −18.35. However, after maximum light, this SN has unusual spectroscopic features, a large degree of line blending, significant line blanketing in the blue (λ < 5000 Å), and strong Ca ii absorption features during and after peak brightness. These unusual spectral features are similar to models of subluminous thermonuclear explosions, specifically double-detonation models of SNe Ia. Photometrically, SN 2019eix appears to be somewhat brighter with slower decline rates than other double-detonation candidates. We modeled the spectra using the radiative-transfer code TARDIS using SN 1994I (an SN Ic) as a base model to see whether we could reproduce the unusual features of SN 2019eix and found them to be consistent with the exception of the O i feature. We also compared SN 2019eix with double-detonation models and found them to best match the observations of SN 2019eix, but failed to reproduce its full photometric and spectroscopic evolution.