论文标题
异构体对与中子星星合并相关的Kilonova的影响
The impact of isomers on a kilonova associated with neutron star mergers
论文作者
论文摘要
我们首次研究了异构体对与中子星（NSMS）相关的Kilonova的重要性。我们考虑了通过异构体$β^ - $衰减，计算出从NSMS弹出的丰度和能源产生速率（$ \dotε_{\ rm nuc} $）的演变。 We find that for ejecta with electron fraction ($Y_e$) of $0.2-0.3$, $\dotε_{\rm nuc}$ is appreciably changed from those without isomers, due to the large change in timing of $β^-$ decay through the isomeric states of ${}^{123, 125, 127} \rm Sn$ and $ {}^{128} \ rm sb $。特别是，异构体对$ \dotε_ {\ rm nuc} $的影响对于$ y_e \ sim 0.25 $的弹出很突出，这可能会散发出在GW170817中观察到的Kilonova的早期蓝色成分的一小部分。当从基态到其异构状态的激发很重要时，$ {}^{}^{129} \ rm sb $和$ {}^{129，131} \ rm te $的异构体也会导致$ \ dot $ \dotε_{\ rm rm nuc} $。此外，我们证明，如果考虑到异构体，则大量无灯笼的喷射会更好地拟合GW170817中基洛诺瓦的光曲线。
We investigate the significance of isomers on a kilonova associated with neutron star mergers (NSMs) for the first time. We calculate the evolution of abundances and energy generation rates ($\dotε_{\rm nuc}$) of ejecta from NSMs, taking into account $β^-$ decay through isomers. We find that for ejecta with electron fraction ($Y_e$) of $0.2-0.3$, $\dotε_{\rm nuc}$ is appreciably changed from those without isomers, due to the large change in timing of $β^-$ decay through the isomeric states of ${}^{123, 125, 127} \rm Sn$ and ${}^{128} \rm Sb$. In particular, the effects of the isomers on $\dotε_{\rm nuc}$ are prominent for ejecta of $Y_e \sim 0.25$, which could emit a fraction of an early, blue component of a kilonova observed in GW170817. When the excitation from a ground state to its isomeric state is important, the isomers of ${}^{129} \rm Sb$ and ${}^{129, 131} \rm Te$ also cause additional and appreciable change in $\dotε_{\rm nuc}$. Furthermore, we demonstrate that larger amounts of lanthanide-free ejecta result in a better fit of an observed light curve of the kilonova in GW170817 if the isomers are taken into account.
