FORMATION AND EVOLUTION OF DUST IN TYPE IIb SUPERNOVAE WITH APPLICATION TO THE CASSIOPEIA A SUPERNOVA REMNANT
FORMATION AND EVOLUTION OF DUST IN TYPE IIb SUPERNOVAE WITH APPLICATION TO THE CASSIOPEIA A SUPERNOVA REMNANT
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DOI：
10.1088/0004-637x/713/1/356
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发表时间：
2009-09
期刊：
影响因子：
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通讯作者：
T. Nozawa;T. Kozasa;N. Tominaga;K. Maeda;H. Umeda;K. Nomoto;O. Krause
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文献类型：
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作者：
T. Nozawa;T. Kozasa;N. Tominaga;K. Maeda;H. Umeda;K. Nomoto;O. Krause
核心崩塌超新星(CCSNe)喷出物中形成并注入星际介质(ISM)的尘埃的数量和大小取决于CCSNe的类型和其外层包层的不同厚度。最近，Cas A被鉴定为IIb型SN(SN IIb)，其特征是小质量的氢包膜。为了阐明在抛射物中形成并提供给ISM的尘埃量如何依赖于CCSNe的类型，我们考虑了星周介质(CSM)的两种密度结构(均匀分布和幂函数分布)，研究了SN IIb抛射物中尘埃颗粒的形成及其在SN残留物中的激波气体中的演化。在此基础上，我们还模拟了激波加热尘埃在SNR中的热发射随时间的演化，并与Cas A SNR的观测结果进行了比较。我们发现，SNIIb喷发出的尘埃总质量高达0.167 M☉，但尘埃的平均半径小于0.01μm，与SNE II-P中大质量氢包层的尘埃有很大不同；在小质量氢包层爆炸中，膨胀的He核经历的减速很小，导致He核内的气体密度太低，不利于大颗粒的形成。此外，SN IIb的低质量氢包络导致反向激波提前到达尘埃形成区。如果CSM呈球状，则当CSM氢密度为NH>；0.1cmISM时，在相对密度较高的冲击气中，新形成的细小颗粒将被完全破坏，而无需注入到−中。然而，实际的CSM很可能是非球形的，因此一部分尘埃颗粒可以被抛入ISM而不受冲击。我们证明了尘埃热发射的光谱能量分布(SED)的时间演化是对环境气体密度和结构敏感的，这影响了反向激波进入抛射物的通道。因此，SED演化反映了尘埃通过溅射和随机加热的侵蚀演化。对于CaS A，我们考虑了M☉yr−1在超巨相期间的稳定质量损失所产生的CSM。然后我们发现，由0.008 M☉激波加热的暖尘埃和0.072 M☉未激波的冷尘埃组成的0.08M☉新形成的尘埃的热发射合理地再现了观测到的CaS A的红外SED。
The amount and size of dust formed in the ejecta of core-collapse supernovae (CCSNe) and injected into the interstellar medium (ISM) depend on the type of CCSNe through the varying thicknesses of their outer envelopes. Recently Cas A was identified as a Type IIb SN (SN IIb) that is characterized by a small-mass hydrogen envelope. In order to clarify how the amount of dust formed in the ejecta and supplied into the ISM depends on the type of CCSNe, we investigate the formation of dust grains in the ejecta of an SN IIb and their evolution in the shocked gas in the SN remnant (SNR) by considering two sets of density structures (uniform and power-law profiles) for the circumstellar medium (CSM). Based on these calculations, we also simulate the time evolution of thermal emission from the shock-heated dust in the SNR and compare the results with the observations of Cas A SNR. We find that the total mass of dust formed in the ejecta of an SN IIb is as large as 0.167 M☉ but the average radius of dust is smaller than 0.01 μm and is significantly different from those in SNe II-P with massive hydrogen envelopes; in the explosion with the small-mass hydrogen envelope, the expanding He core undergoes little deceleration, so that the gas density in the He core is too low for large-sized grains to form. In addition, the low-mass hydrogen envelope of the SN IIb leads to the early arrival of the reverse shock at the dust-forming region. If the CSM is more or less spherical, then the newly formed small grains would be completely destroyed in the relatively dense shocked gas for the CSM hydrogen density of nH>0.1 cm−3 without being injected into the ISM. However, the actual CSM is likely to be non-spherical, so a portion of the dust grains could be ejected into the ISM without being shocked. We demonstrate that the temporal evolution of the spectral energy distribution (SED) by thermal emission from dust is sensitive to the ambient gas density and structure that affects the passage of the reverse shock into the ejecta. Thus, the SED evolution reflects the evolution of dust through erosion by sputtering and stochastic heating. For Cas A, we consider the CSM produced by the steady mass loss of M☉ yr−1 during the supergiant phase. Then we find that the observed infrared SED of Cas A is reasonably reproduced by thermal emission from the newly formed dust of 0.08 M☉, which consists of the 0.008 M☉ shock-heated warm dust and 0.072 M☉ unshocked cold dust.