The Transformation of SN1987A into a Supernova Remnant

超新星1987A是近四个世纪以来观测到的距离最近的超新星，也是迄今为止研究最深入的超新星。随着爆炸喷出的物质撞击过去100万年中恒星脱落的星周包层，超新星1987A正迅速变成一颗超新星残骸。我们建议使用光学、红外和紫外程序的组合来观察这一过程，再加上进一步的天基研究（由美国宇航局支持）。这将使我们能够绘制出包络层的结构，包括其未受扰动状态和被喷出物破坏的状态。这将使对SN遗迹形成演化的首次完整研究成为可能。我们之前对三维结构、速度、密度和组成的观察将确定爆炸前星云的性质和形成它的质量损失过程，而碰撞中产生的X和EUV通量对星云的激发将使我们能够再次重新分析它。除了这些前所未有的SN遗迹研究之外，我们还将继续利用SN爆炸的光回波来探索剑鱼座30恒星形成区的星际介质，研究从震波爆发穿过祖先恒星表面的紫外线脉冲的回波，并准确确定到大麦哲伦云的距离（这是银河系外距离阶梯上的一个基本梯级）

AST-0206048CrottsSupernova 1987A, the closest SN seen in nearly four centuries, and the most intenselystudied ever, is rapidly turning into a SN remnant as the ejecta from the explosion nowstrikes the circumstellar envelope shed by the star over the last million years. We proposeto observe this process using a combination of optical, IR and UV programs, plus furtherspace-based studies (supported by NASA). These will allow us to map the structure ofthe envelope, both in its unperturbed state and as it is destroyed by the ejecta. Thiswill allow the first complete study of SN remnant formation evolution ever undertaken.Our previous observations of the 3-D structure, velocities, density and composition willestablish the nature of the pre-explosion nebula and the mass loss processes that created it,while the excitation of this nebula by the X and EUV flux created in the collision will allowus to re-analyze it once more. In addition to these unprecedented studies of a SN remnant,will continue to use light echoes from the SN explosion to explore the interstellarmedium in the 30 Doradus star-formation region, to study the echo of the UV pulse fromSN shock breakout through the progenitor star's surface, and to accurately determine thedistance to the Large Magellanic Cloud { a fundamental rung on the extragalactic distanceladder.***