The origin of dust in galaxies revisited: the mechanism determining dust content
The origin of dust in galaxies revisited: the mechanism determining dust content
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重新审视星系中尘埃的起源：决定尘埃含量的机制
DOI：
10.5047/eps.2011.02.013
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
A. Inoue
中科院分区：
文献类型：
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作者：
A. Inoue
宇宙尘埃的起源是行星科学中的一个基本问题。本文利用由恒星、星际介质、金属（比氦重的元素）和尘埃组成的星系的化学演化模型，重新探讨了星系，特别是银河系中尘埃的起源。我们开始从四个组件的时间演化方程的审查，然后，我们提出了简单的食谱恒星残余质量和产量的金属和尘埃的基础上恒星核合成和尘埃形成的模型。在用太阳邻域的观测数据对模型参数进行校正后，我们证实了如果理论工作所建议的尘埃破坏效率是正确的，那么恒星尘埃产生率相对于超新星尘埃破坏率是不足的。如果分子云中物质吸积引起的尘埃质量增长是活跃的，那么在太阳附近观测到的尘埃量就被重现了。我们提出了一个明确的分析解释的机制，用于确定星系中的尘埃含量后，激活的吸积增长：吸积增长和超新星破坏之间的平衡。因此，尘埃含量是独立的恒星尘埃产量的不确定性后的增长激活。活化的时间由取决于生长和破坏效率的临界金属质量分数决定。太阳系的形成似乎发生在激活之后很久，在原太阳星云中存在大量的尘埃。
The origin of cosmic dust is a fundamental issue in planetary science. This paper revisits the origin of dust in galaxies, in particular, in the Milky Way, by using a chemical evolution model of a galaxy composed of stars, interstellar medium, metals (elements heavier than helium), and dust. We start from a review of time-evolutionary equations of the four components, and then, we present simple recipes for the stellar remnant mass and yields of metal and dust based on models of stellar nucleosynthesis and dust formation. After calibrating some model parameters with the data from the solar neighborhood, we have confirmed a shortage of the stellar-dust-production rate relative to the dust-destruction rate by supernovae if the destruction efficiency suggested by theoretical works is correct. If the dust-mass growth by material accretion in molecular clouds is active, the observed dust amount in the solar neighborhood is reproduced. We present a clear analytic explanation of the mechanism for determining dust content in galaxies after the activation of accretion growth: a balance between accretion growth and supernova destruction. Thus, the dust content is independent of the uncertainty of the stellar dust yield after the growth activation. The timing of the activation is determined by a critical metal mass fraction which depends on the growth and destruction efficiencies. The solar system formation seems to have occurred well after the activation and plenty of dust would have existed in the proto-solar nebula.