Dunne Loretta, Eales Stephen, Ivison Rob, Morgan Haley, Edmunds Mike
Department of Physics and Astronomy, Cardiff University, 5 The Parade, Cardiff CF24 3YB, UK.
Nature. 2003 Jul 17;424(6946):285-7. doi: 10.1038/nature01792.
Large amounts of dust (>10(8)M(o)) have recently been discovered in high-redshift quasars and galaxies corresponding to a time when the Universe was less than one-tenth of its present age. The stellar winds produced by stars in the late stages of their evolution (on the asymptotic giant branch of the Hertzsprung-Russell diagram) are thought to be the main source of dust in galaxies, but they cannot produce that dust on a short enough timescale (&<1 Gyr) to explain the results in the high-redshift galaxies. Supernova explosions of massive stars (type II) are also a potential source, with models predicting 0.2-4M(o) of dust. As massive stars evolve rapidly, on timescales of a few Myr, these supernovae could be responsible for the high-redshift dust. Observations of supernova remnants in the Milky Way, however, have hitherto revealed only 10(-7)-10(-3)M(o) each, which is insufficient to explain the high-redshift data. Here we report the detection of approximately 2-4M(o) of cold dust in the youngest known Galactic supernova remnant, Cassiopeia A. This observation implies that supernovae are at least as important as stellar winds in producing dust in our Galaxy and would have been the dominant source of dust at high redshifts.
最近在高红移类星体和星系中发现了大量尘埃（>10⁸M⊙），这对应于宇宙年龄还不到目前年龄十分之一的时期。恒星在其演化后期（在赫罗图的渐近巨星分支上）产生的星风被认为是星系中尘埃的主要来源，但它们无法在足够短的时间尺度（<10亿年）内产生这些尘埃，以解释高红移星系中的观测结果。大质量恒星（II型）的超新星爆发也是一个潜在来源，模型预测可产生0.2 - 4M⊙的尘埃。由于大质量恒星演化迅速，时间尺度为几百万年，这些超新星可能是高红移尘埃的来源。然而，迄今为止对银河系中超新星遗迹的观测显示，每个遗迹的尘埃量仅为10⁻⁷ - 10⁻³M⊙，不足以解释高红移数据。在此，我们报告在已知最年轻的银河系超新星遗迹仙后座A中检测到约2 - 4M⊙的冷尘埃。这一观测结果表明，超新星在我们银河系中产生尘埃方面至少与星风同样重要，并且在高红移时可能是尘埃的主要来源。
