Helium as a signature of the double detonation in Type Ia supernovae
Helium as a signature of the double detonation in Type Ia supernovae
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氦作为 Ia 型超新星双重爆炸的标志
DOI：
10.1093/mnras/stad2170
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发表时间：
2023
影响因子：
4.8
通讯作者：
Kromer, Markus
中科院分区：
文献类型：
--
作者：
Collins, Christine E.;Sim, Stuart A.;Shingles, Luke J.;Gronow, Sabrina;Röpke, Friedrich K.;Pakmor, Rüdiger;Seitenzahl, Ivo R.;Kromer, Markus
双爆轰是一种被广泛讨论的解释Ia型超新星的机制，它来自于亚克拉塞卡质量的白色矮星的爆炸。在这种情况下，氦爆炸在碳/氧白色矮星的表面氦壳层中被点燃，这导致二次碳爆炸。爆炸模拟预测高丰度的未燃烧的氦在喷出物中，然而，辐射传输模拟还没有能够完全解决氦光谱特征是否会形成。这是因为氦不能通过热过程被充分激发以形成光谱特征，但可以通过与非热电子的碰撞被激发，这是大多数研究所忽略的。我们对一个双爆轰爆炸模型的实例进行了完整的非局域热力学平衡辐射传输模拟，并包括了对快电子的非热处理。我们发现了一个明显的Heiλ10830特征，在爆发后的最初几天内最强，并随着时间的推移而减弱。最初，这个特征与M10927特征混合，但随着时间的推移，M10927特征的蓝翼分离成次要特征。我们将我们的模拟与iPTF 13 ebh的观测结果进行了比较，iPTF 13 ebh显示出与先前确定为Ci的M10927特征的蓝色机翼相似的特征。我们的模拟结果与这一特征的演变很好地吻合，我们将其识别为高速Heiλ10830。这表明Heiλ10830可能是双重爆炸情景的标志。
The double detonation is a widely discussed mechanism to explain Type Ia supernovae from explosions of sub-Chandrasekhar mass white dwarfs. In this scenario, a helium detonation is ignited in a surface helium shell on a carbon/oxygen white dwarf, which leads to a secondary carbon detonation. Explosion simulations predict high abundances of unburnt helium in the ejecta, however, radiative transfer simulations have not been able to fully address whether helium spectral features would form. This is because helium can not be sufficiently excited to form spectral features by thermal processes, but can be excited by collisions with non-thermal electrons, which most studies have neglected. We carry out a full non-local thermodynamic equilibrium radiative transfer simulation for an instance of a double detonation explosion model, and include a non-thermal treatment of fast electrons. We find a clear Heiλ10830 feature which is strongest in the first few days after explosion and becomes weaker with time. Initially this feature is blended with the Mgiiλ10927 feature but over time separates to form a secondary feature to the blue wing of the Mgiiλ10927 feature. We compare our simulation to observations of iPTF13ebh, which showed a similar feature to the blue wing of the Mgiiλ10927 feature, previously identified as Ci. Our simulation shows a good match to the evolution of this feature and we identify it as high velocity Heiλ10830. This suggests that Heiλ10830 could be a signature of the double detonation scenario.