Krause Oliver, Birkmann Stephan M, Rieke George H, Lemke Dietrich, Klaas Ulrich, Hines Dean C, Gordon Karl D
Steward Observatory, University of Arizona, 933 N Cherry Avenue, Tucson, Arizona 85721, USA.
Nature. 2004 Dec 2;432(7017):596-8. doi: 10.1038/nature03110.
A large amount (about three solar masses) of cold (18 K) dust in the prototypical type II supernova remnant Cassiopeia A was recently reported. It was concluded that dust production in type II supernovae can explain how the large quantities (approximately 10(8) solar masses) of dust observed in the most distant quasars could have been produced within only 700 million years after the Big Bang. Foreground clouds of interstellar material, however, complicate the interpretation of the earlier submillimetre observations of Cas A. Here we report far-infrared and molecular line observations that demonstrate that most of the detected submillimetre emission originates from interstellar dust in a molecular cloud complex located in the line of sight between the Earth and Cas A, and is therefore not associated with the remnant. The argument that type II supernovae produce copious amounts of dust is not supported by the case of Cas A, which previously appeared to provide the best evidence for this possibility.
最近有报道称，在典型的II型超新星遗迹仙后座A中存在大量（约三个太阳质量）低温（18K）尘埃。研究得出结论，II型超新星中的尘埃产生可以解释在大爆炸后仅7亿年内如何产生了在最遥远类星体中观测到的大量（约10⁸个太阳质量）尘埃。然而，星际物质的前景云团使早期对仙后座A的亚毫米波观测的解释变得复杂。在此我们报告远红外和分子线观测结果，这些观测表明，检测到的大部分亚毫米波辐射源自位于地球与仙后座A之间视线方向上的一个分子云复合体中的星际尘埃，因此与该遗迹无关。II型超新星产生大量尘埃这一观点并未得到仙后座A这一案例的支持，而仙后座A此前似乎为这种可能性提供了最佳证据。
