SN 2020bio: A Double-peaked, H-poor Type IIb Supernova with Evidence of Circumstellar Interaction
SN 2020bio: A Double-peaked, H-poor Type IIb Supernova with Evidence of Circumstellar Interaction
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DOI：
10.3847/1538-4357/ace595
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发表时间：
2023-01
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通讯作者：
C. Pellegrino;D. Hiramatsu;I. Arcavi;D. Howell;K. Bostroem;P. J. Brown;J. Burke;N. Elias-Rosa;K. Itagaki;H. Kaneda;C. McCully;M. Modjaz;E. P. Gonzalez;T. Pritchard;N. Yesmin
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作者：
C. Pellegrino;D. Hiramatsu;I. Arcavi;D. Howell;K. Bostroem;P. J. Brown;J. Burke;N. Elias-Rosa;K. Itagaki;H. Kaneda;C. McCully;M. Modjaz;E. P. Gonzalez;T. Pritchard;N. Yesmin
我们目前的光度和光谱观测SN 2020 bio，双峰IIb型超新星（SN）在爆炸的一天内发现，主要由拉斯坎布雷斯天文台和斯威夫特获得。SN 2020 bio在其光变曲线的第一周显示出快速而持久的初始下降，与其他研究充分的IIb型SNe相似。这种早期的辐射被认为是起源于被SN爆炸冲击加热的祖先星星的富氢（H）外层的冷却。我们将SN 2020 bio与其他双峰IIb型SNe样本进行比较，以研究其祖细胞特性。分析模型拟合早期的发射给出了与其他IIb型超新星一致的祖先半径（100-1500 R）和富氢包层质量（0.01-0.5 M）的估计。然而，SN 2020 bio显示出几个特点，包括（1）弱H光谱特征，表明比其他IIb型祖先有更大的质量损失;（2）不发光的二次光曲线峰，意味着少量合成的56 Ni（M Ni ≈0.02 M ⊙）;和（3）低光度星云[O i]和相互作用驱动的星云特征。这些观测结果与一个较低质量的祖先（M ZAMS 12 M）更一致，该祖先在爆炸前被剥离了大部分富含H的外壳。这项研究增加了IIb型SNe及其祖细胞观察到的特性的多样性。
We present photometric and spectroscopic observations of SN 2020bio, a double-peaked Type IIb supernova (SN) discovered within a day of explosion, primarily obtained by Las Cumbres Observatory and Swift. SN 2020bio displays a rapid and long-lasting initial decline throughout the first week of its light curve, similarly to other well-studied Type IIb SNe. This early-time emission is thought to originate from the cooling of the extended outer hydrogen-rich (H-rich) envelope of the progenitor star that is shock heated by the SN explosion. We compare SN 2020bio to a sample of other double-peaked Type IIb SNe in order to investigate its progenitor properties. Analytical model fits to the early-time emission give progenitor radius (≈100–1500 R ⊙) and H-rich envelope mass (≈0.01–0.5 M ⊙) estimates that are consistent with other Type IIb SNe. However, SN 2020bio displays several peculiarities, including (1) weak H spectral features indicating a greater amount of mass loss than other Type IIb progenitors; (2) an underluminous secondary light-curve peak that implies a small amount of synthesized 56Ni (M Ni ≈0.02 M ⊙); and (3) low-luminosity nebular [O i] and interaction-powered nebular features. These observations are more consistent with a lower-mass progenitor (M ZAMS ≈ 12 M ⊙) that was stripped of most of its H-rich envelope before exploding. This study adds to the growing diversity in the observed properties of Type IIb SNe and their progenitors.