RATES AND DELAY TIMES OF TYPE Ia SUPERNOVAE
RATES AND DELAY TIMES OF TYPE Ia SUPERNOVAE
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DOI：
10.1088/0004-637x/699/2/2026
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发表时间：
2009-04
期刊：
影响因子：
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通讯作者：
A. Ruiter;K. Belczynski;Chris L. Fryer
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文献类型：
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作者：
A. Ruiter;K. Belczynski;Chris L. Fryer
我们通过分析双星的演化来计算最有希望的Ia型超新星（SNe Ia）原生体的合成率和延迟时间。我们介绍并讨论了白矮星（WD）达到钱德拉塞卡质量并有可能在Ia型超新星中爆发的演化情景。我们考虑了双变质（DDS；两个白矮星合并）、单变质（SDS；白矮星从富含H的伴星吸积）和AM Canum Venaticorum（AM CVn；白矮星从富含H的伴星吸积）三种情况。结果显示了两种不同的恒星形成历史：爆发（类椭圆星系）和连续（类螺旋星系）。研究发现，在我们的标准模型中（普通包层效率 αCE = 1），DDS 的延迟时间呈幂律分布。我们注意到SDS的延迟时间范围很宽，而AM CVn原生体在早期会产生短暂的SNE Ia爆发。根据假定的αCE，DDS的中位延迟时间介于0.5和1 Gyr之间；SDS介于2和3 Gyr之间；AM CVn介于0.8和0.6 Gyr之间。对于一个类银河系（MW-like），我们估计由不同原生星产生的SNE Ia的速率为：SDS和AM CVn为∼10-4 yr-1，DDS为∼10-3 yr-1。我们指出，只有两个合并的碳氧WD（DDS中发现的唯一系统）的速率与典型的类MW螺旋的观测速率一致。我们还注意到，DDS原生星是椭圆星系中的主要星群。DDS 的延迟时间分布遵循一个幂律，这意味着更多的 SNe Ia（单位质量）发生在年轻而非衰老的群体中。我们的结果并不排除其他情况，但强烈表明，至少在我们采用的演化模型框架内，DDS是螺旋星系中产生SNe Ia的主要通道。鉴于目前对吸积 WD 的理解，人们认为 WD 合并不可能产生热核爆炸，因此要么是进化计算和吸积物理学不正确，要么是爆炸计算不准确，需要重新研究。
We analyze the evolution of binary stars to calculate synthetic rates and delay times of the most promising Type Ia Supernovae (SNe Ia) progenitors. We present and discuss evolutionary scenarios in which a white dwarf (WD) reaches the Chandrasekhar mass and potentially explodes in a SNe Ia. We consider Double Degenerate (DDS; merger of two WDs), Single Degenerate (SDS; WD accreting from H-rich companion), and AM Canum Venaticorum (AM CVn; WD accreting from He-rich companion) scenarios. The results are presented for two different star formation histories: burst (elliptical-like galaxies) and continuous (spiral-like galaxies). It is found that delay times for the DDS in our standard model (with common envelope efficiency αCE = 1) follow a power-law distribution. For the SDS we note a wide range of delay times, while AM CVn progenitors produce a short burst of SNe Ia at early times. The DDS median delay time falls between ∼0.5 and 1 Gyr; the SDS between ∼2 and 3 Gyr; and the AM CVn between ∼0.8 and 0.6 Gyr depending on the assumed αCE. For a Milky-Way-like (MW-like) galaxy, we estimate the rates of SNe Ia arising from different progenitors as: ∼10−4 yr−1 for the SDS and AM CVn, and ∼10−3 yr−1 for the DDS. We point out that only the rates for two merging carbon–oxygen WDs, the only systems found in the DDS, are consistent with the observed rates for typical MW-like spirals. We also note that DDS progenitors are the dominant population in elliptical galaxies. The fact that the delay time distribution for the DDS follows a power law implies more SNe Ia (per unit mass) in young rather than in aged populations. Our results do not exclude other scenarios, but strongly indicate that the DDS is the dominant channel generating SNe Ia in spiral galaxies, at least in the framework of our adopted evolutionary models. Since it is believed that WD mergers cannot produce a thermonuclear explosion given the current understanding of accreting WDs, either the evolutionary calculations along with accretion physics are incorrect, or the explosion calculations are inaccurate and need to be revisited.