Off-centre carbon burning in He-accreting carbon-oxygen white dwarfs
Off-centre carbon burning in He-accreting carbon-oxygen white dwarfs
复制标题
He 吸积碳氧白矮星中的偏心碳燃烧
DOI：
10.1093/mnras/stz1028
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发表时间：
2019
影响因子：
4.8
通讯作者：
王博
中科院分区：
文献类型：
--
作者：
Wu Chengyuan;王博
碳氧白矮星(CO WD) + He星通道是产生Ia型超新星（SNe Ia）的一种很有希望的短延迟方式。最近的研究发现，当CO WD的质量吸积速率高于临界速率（约）时，He壳下的碳可以被点燃，引发向内传播的碳火焰。以前的研究通常认为，偏离中心的碳火焰会到达中心，导致氧氖（ONe） WD的形成，最终坍缩成中子星。然而，对离中心碳燃烧过程的研究并不充分。这可能导致CO - WDs的最终命运存在一些不确定性。采用台地模型，模拟了高吸合二氧化碳排放区离中心碳燃烧的长期演化过程。我们发现，由于燃烧锋面的高温，向内传播的碳火焰直接将CO WDs转化为OSi核心，而不是ONe核心。我们认为CO WDs的最终命运可能是在偏离中心的碳燃烧条件下的OSi WDs，或者在质量吸积继续的情况下作为铁核坍缩SNe爆炸。我们还发现OSi核心中硅的质量分数对质量吸积率敏感。
The carbon–oxygen white dwarf (CO WD) + He star channel is one of the promising ways for producing type Ia supernovae (SNe Ia) with short delay times. Recent studies found that carbon under the He shell can be ignited if the mass-accretion rate of CO WD is higher than a critical rate (about), triggering an inwardly propagating carbon flame. Previous studies usually supposed that the off-centre carbon flame would reach the centre, resulting in the formation of an oxygen–neon (ONe) WD that will collapse into a neutron star. However, the process of off-centre carbon burning is not well studied. This may result in some uncertainties on the final fates of CO WDs. By employingmesa, we simulated the long-term evolution of off-centre carbon burning in He-accreting CO WDs. We found that the inwardly propagating carbon flame transforms the CO WDs into OSi cores directly but not ONe cores owing to the high temperature of the burning front. We suggest that the final fates of the CO WDs may be OSi WDs under the conditions of off-centre carbon burning, or explode as iron-core-collapse SNe if the mass accretion continues. We also found that the mass fractions of silicon in the OSi cores are sensitive to the mass-accretion rates.