Krause Oliver, Birkmann Stephan M, Usuda Tomonori, Hattori Takashi, Goto Miwa, Rieke George H, Misselt Karl A
Max-Planck-Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany.
Science. 2008 May 30;320(5880):1195-7. doi: 10.1126/science.1155788.
Cassiopeia A is the youngest supernova remnant known in the Milky Way and a unique laboratory for supernova physics. We present an optical spectrum of the Cassiopeia A supernova near maximum brightness, obtained from observations of a scattered light echo more than three centuries after the direct light of the explosion swept past Earth. The spectrum shows that Cassiopeia A was a type IIb supernova and originated from the collapse of the helium core of a red supergiant that had lost most of its hydrogen envelope before exploding. Our finding concludes a long-standing debate on the Cassiopeia A progenitor and provides new insight into supernova physics by linking the properties of the explosion to the wealth of knowledge about its remnant.
仙后座A是银河系中已知最年轻的超新星遗迹，也是超新星物理学的一个独特实验室。我们展示了仙后座A超新星在接近最大亮度时的光谱，该光谱是通过对散射光回波的观测获得的，此时距离爆炸的直接光线扫过地球已经过去了三个多世纪。光谱显示仙后座A是一颗IIb型超新星，起源于一颗红色超巨星的氦核坍缩，这颗红色超巨星在爆炸前已经失去了大部分氢包层。我们的发现结束了关于仙后座A前身星的长期争论，并通过将爆炸的特性与关于其遗迹的丰富知识联系起来，为超新星物理学提供了新的见解。
