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arXiv · 1405.0173

What sodium absorption lines tell us about type Ia supernovae

Noam Soker
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Abstract

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.

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Noam Soker. 2014-07-21. What sodium absorption lines tell us about type Ia supernovae. https://doi.org/10.1093/mnrasl%2Fslu119

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