THE ROLE OF TYPE Ia SUPERNOVAE IN CHEMICAL EVOLUTION. I. LIFETIME OF TYPE Ia SUPERNOVAE AND METALLICITY EFFECT
THE ROLE OF TYPE Ia SUPERNOVAE IN CHEMICAL EVOLUTION. I. LIFETIME OF TYPE Ia SUPERNOVAE AND METALLICITY EFFECT
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DOI：
10.1088/0004-637x/707/2/1466
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发表时间：
2007-12
期刊：
影响因子：
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通讯作者：
C. Kobayashi;K. Nomoto
中科院分区：
文献类型：
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作者：
C. Kobayashi;K. Nomoto
在单简并假设的基础上，考虑了白矮风的金属丰度相关性和双星质量剥离效应，建立了一个新的Ia型超新星模型。我们的模型自然地预测了SnIa寿命分布在0.1Gyr-20Gyr的范围内，在∼0.1Gyr和1Gyr处有双峰。目前椭圆星系中的SNIa率可以用红巨星+WD系统的老年群体来再现，而射电星系中的大SNIa率可以用主序+WD系统的年轻群体来解释。由于金属丰度效应，即由于双星系统中没有来自WDS的风，在具有[Fe/H]≲−1的系统中，例如高z旋涡星系，SNIa率被认为是非常小的。与双简并假设等其他模型相比，我们的SN Ia模型能更好地再现太阳近邻的[(α，Mn，Zn)/Fe]-[Fe/H]关系。当SneIa的年轻群体存在时，金属丰度效应是更需要的。我们还成功地再现了星系超新星速率及其对星系形态类型的依赖关系，以及宇宙超新星速率历史，峰值在z∼1。在z≳1，预测的超新星速率向更高的红移方向下降，只有在化学富集度较短的系统中才能观察到SNIa。这表明超新星宇宙学中的演化效应可能很小。
We construct a new model of Type Ia Supernovae (SNe Ia), based on the single degenerate scenario, taking account of the metallicity dependences of white dwarf (WD) wind and the mass-stripping effect on the binary companion star. Our model naturally predicts that SN Ia lifetime distribution spans a range of 0.1–20 Gyr with the double peaks at ∼0.1 and 1 Gyr. While the present SN Ia rate in elliptical galaxies can be reproduced with the old population of the red giants+WD systems, the large SN Ia rate in radio galaxies could be explained with the young population of the main-sequence+WD systems. Because of the metallicity effect, i.e., because of the lack of winds from WDs in the binary systems, the SN Ia rate in the systems with [Fe/H] ≲−1, e.g., high-z spiral galaxies, is supposed to be very small. Our SN Ia model can give better reproduction of the [(α, Mn, Zn)/Fe]–[Fe/H] relations in the solar neighborhood than other models such as the double-degenerate scenario. The metallicity effect is more strongly required in the presence of the young population of SNe Ia. We also succeed in reproducing the galactic supernova rates with their dependence on the morphological type of galaxies, and the cosmic SN Ia rate history with a peak at z ∼ 1. At z ≳ 1, the predicted SN Ia rate decreases toward higher redshifts and SNe Ia will be observed only in the systems that have evolved with a short timescale of chemical enrichment. This suggests that the evolution effect in the supernova cosmology can be small.