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arXiv 1105.0936astro-ph.HEastro-ph.SR
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Ia型超新星爆炸前沸腾过程中的G模激发

G-Mode Excitation During the Pre-explosive Simmering of Type Ia Supernovae

Anthony L. Piro

摘要:

在一颗白矮星(WD)爆炸性燃烧形成Ia型超新星(SN Ia)之前,这颗恒星在一个对流的碳燃烧区“沸腾”了大约10^3年。我估计在这一阶段的对流g模式的激发,并探讨其可能对WD的影响。当这些模式从WD的核心向其表面传播时,它们的振幅随着密度的减小而增大。一旦这些模式达到非线性振幅,它们就会破裂并将其能量沉积到质量为~10^{-4}M_ \odot的壳层中。这使表面温度升高了6*10^8 K,这足以点燃一层氦,这在某些Ia超新星的情况下是可能存在的。这主要合成28 Si、32 S、40 Ca和一些44 Ti。这些灰烬在随后的爆炸中膨胀,速度高达20,000 km/s,这可以解释在许多Ia超新星中看到的高速特征(HVFs)。因此,HVFs的出现将是一个有用的判别确定之间的祖先,因为易燃的富氦层将不会存在的C/O WD的吸积在合并的情况下。我还讨论了44 Ti生产的影响。

英文摘要:

Prior to the explosive burning of a white dwarf (WD) that makes a Type Ia supernova (SN Ia), the star "simmers" for ~10^3 yrs in a convecting, carbon burning region. I estimate the excitation of g-modes by convection during this phase and explore their possible affect on the WD. As these modes propagate from the core of the WD toward its surface, their amplitudes grow with decreasing density. Once the modes reach nonlinear amplitudes, they break and deposit their energy into a shell of mass ~10^{-4}M_\odot. This raises the surface temperature by 6*10^8 K, which is sufficient to ignite a layer of helium, as is expected to exist for some SN Ia scenarios. This predominantly synthesizes 28Si, 32S, 40Ca, and some 44Ti. These ashes are expanded out with the subsequent explosion up to velocities of ~20,000 km/s, which may explain the high velocity features (HVFs) seen in many SNe Ia. The appearance of HVFs would therefore be a useful discriminant for determining between progenitors, since a flammable helium-rich layer will not be present for accretion from a C/O WD as in a merger scenario. I also discuss the implications of 44Ti production.

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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