RCW 86：历史超新星遗迹
(原标题: RCW 86: Historical Supernova Remnant)
2023-03-03
浏览次数: 17
公元185年，中国天文学家记录了南门星群出现了一颗新星。在现代星图上，这部分天空被认为是半人马座α星和β星。这颗新星在几个月的时间里都是肉眼可见的，现在被认为是有记录以来最早的超新星。这张深望远镜照片显示了发射星云RCW 86的纤细轮廓，在繁星点点的背景下刚好可见，它被认为是那次恒星爆炸的遗迹。这张照片是由智利塞罗·托洛洛美洲天文台的宽视场暗能量相机拍摄的，它追踪了被仍在膨胀的冲击波电离的不规则气体外壳的全部范围。天基图像显示，RCW 86富含铁元素，而残骸中没有中子星或脉冲星，这表明最初的超新星是Ia型。与大质量恒星的核心坍缩超新星爆炸不同，Ia型超新星是一颗白矮星上的热核爆炸，它从双星系统的伴星中吸积物质。在我们银河系的平面附近，比天空中的满月还要大，这颗超新星的遗迹太暗了，肉眼无法看到。rcw86距离地球约8000光年，直径约100光年。
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In 185 AD, Chinese astronomers recorded the appearance of a new star in the Nanmen asterism. That part of the sky is identified with Alpha and Beta Centauri on modern star charts. The new star was visible to the naked-eye for months, and is now thought to be the earliest recorded supernova. This deep telescopic view reveals the wispy outlines of emission nebula RCW 86, just visible against the starry background, understood to be the remnant of that stellar explosion. Captured by the wide-field Dark Energy Camera operating at Cerro Tololo Inter-American Observatory in Chile, the image traces the full extent of a ragged shell of gas ionized by the still expanding shock wave. Space-based images indicate an abundance of the element iron in RCW 86 and the absence of a neutron star or pulsar within the remnant, suggesting that the original supernova was Type Ia. Unlike the core collapse supernova explosion of a massive star, a Type Ia supernova is a thermonuclear detonation on a white dwarf star that accretes material from a companion in a binary star system. Near the plane of our Milky Way galaxy and larger than the full moon on the sky this supernova remnant is too faint to be seen by eye though. RCW 86 is some 8,000 light-years distant and around 100 light-years across.