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arXiv 1005.3092astro-ph.SR
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Ia型超新星产生的白矮星的冷却时间

The cooling time of white dwarfs produced from type Ia supernovae

Xiang-Cun Meng, Wu-Ming Yang, Zhong-Mu Li

摘要:

Ia型超新星(SNe Ia)是测量宇宙学参数的关键,其中Phillips关系被采用。然而,这种关系的起源仍然不清楚。提出了几个参数,如碳氧比(C/O)和点火时白矮星(WD)的中心密度。这些参数主要取决于WD的初始质量和冷却时间。利用孟和杨发展的先驱体模型,我们给出了初始WD质量和冷却时间的分布。我们没有发现这些参数之间的任何相关性。然而,我们注意到,WD的质量范围减小,而其平均值增加的冷却时间。这些结果可以在模拟超新星Ia爆炸时提供约束,即具有高C/O比的WDs通常在点火时具有较低的中心密度,而具有最高中心密度的WDs通常具有较低的C/O比。冷却时间主要由次生烃的演化年龄决定,冷却时间的离散度随演化年龄的增大而减小。我们的结果可能表明,冷却时间长的WD比冷却时间短的WD具有更均匀的性质,这可能有助于解释为什么椭圆星系中的SNe Ia比螺旋星系中的SNe Ia具有更均匀的最大光度。

英文摘要:

Type Ia supernovae (SNe Ia) play a key role in measuring cosmological parameters, in which the Phillips relation is adopted. However, the origin of the relation is still unclear. Several parameters are suggested, e.g. the relative content of carbon to oxygen (C/O) and the central density of the white dwarf (WD) at ignition. These parameters are mainly determined by the WD's initial mass and its cooling time, respectively. Using the progenitor model developed by Meng and Yang, we present the distributions of the initial WD mass and the cooling time. We do not find any correlation between these parameters. However, we notice that the range of the WD's mass decreases, while its average value increases with the cooling time. These results could provide a constraint when simulating the SN Ia explosion, i.e. the WDs with a high C/O ratio usually have a lower central density at ignition, while those having the highest central density at ignition generally have a lower C/O ratio. The cooling time is mainly determined by the evolutionary age of secondaries, and the scatter of the cooling time decreases with the evolutionary age. Our results may indicate that WDs with a long cooling time have more uniform properties than those with a short cooling time, which may be helpful to explain why SNe Ia in elliptical galaxies have a more uniform maximum luminosity than those in spiral galaxies.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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