What sodium absorption lines tell us about Type Ia supernovae
What sodium absorption lines tell us about Type Ia supernovae
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DOI：
10.1093/mnrasl/slu119
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发表时间：
2014-05
影响因子：
4.8
通讯作者：
N. Soker
中科院分区：
文献类型：
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作者：
N. Soker
我们认为，在某些Ia型超新星（SN Ia）中，引起可变NaI - D吸收谱线的钠主要来自距离超新星约1pc的尘埃。在这个从尘埃中吸收钠（NaDA）的模型中，SN Ia的峰值亮度从距离SN 1pc的尘埃中释放钠的过程与彗星接近距离太阳1au时太阳辐射从彗星尘埃中释放钠的过程类似。尘埃颗粒没有升华，而是保持完整，并通过光子刺激解吸（PSD；或光溅射）释放钠。一些Na可能在爆炸前就开始于气相。吸收强度的减弱是由SN的na电离辐射引起的。我们将NaDA模型应用于SN 2006X和SN 2007le，发现它比Na复合模型更符合NaI D吸收谱线的时间变异性。NaDA模型的尘埃壳层的质量太高，无法在超新星Ia的单简并情景中得到解释。因此，在一些SN Ia中存在可变NaI - D线，进一步削弱了SN Ia已经非常有问题的单简并情况。
We propose that the sodium responsible for the variable NaI D absorption lines in some type Ia supernovae (SN Ia) originate mainly from dust residing at ~1 pc from the supernovae. In this Na-from-dust absorption (NaDA) model the process by which the SN Ia peak luminosity releases sodium from dust at 1 pc from the SN is similar to the processes by which solar radiation releases sodium from cometary dust when comets approach a distance of 1 AU from the Sun. The dust grains are not sublimated but rather stay intact, and release sodium by photon-stimulated desorption (PSD; or photo-sputtering). Some of the Na might start in the gas phase before the explosion. Weakening in absorption strength is caused by Na-ionizing radiation of the SN. We apply the NaDA model to SN 2006X and SN 2007le, and find it to comply better with the observed time variability of the NaI D absorption lines than the Na recombination model. The mass in the dusty shell of the NaDA model is much too high to be accounted for in the single-degenerate scenario for SN Ia. Therefore, the presence of variable NaI D lines in some SN Ia further weakens the already very problematic single-degenerate scenario for SN Ia.