Copyright:Chinese astronomers
中文翻譯:
在185年，中國的天文學家們記錄到南門星系出現了一顆新的星星。這片天空的區域在現代星圖上可以找到對應於南方星座半人馬座的一部分。這顆新星被報告能夠在裸眼下可見幾個月，然後才慢慢消失，現在被認為是最早記錄的超新星。在這張21世紀的望遠鏡圖像中，可以看到一片淡淡的發射星雲，這是那場歷史性恆星爆炸的殘骸，與星空背景形成對比。這片名為RCW 86的星雲呈現出破碎卻大致圓形的範圍，它代表著被超新星仍在擴張的震波電離的星際氣體。太空中的圖像顯示RCW 86中有大量的鐵元素，而在這個殘骸中卻缺乏中子星或脈衝星，這暗示著原本的超新星是Ia型的。與大質量恆星的核心塌縮超新星爆炸不同，Ia型超新星是在一顆從伴星系統中累積物質的白矮星上發生的熱核爆炸。這個超新星殘骸位於我們的銀河系平面附近，大小超過滿月，但太過微弱，眼睛無法看到。RCW 86距離地球約8000光年，直徑有約100光年。
原文:
In 185 AD, Chinese astronomers recorded the appearance of a new star in the Nanmen asterism. That part of the sky is identified with part of the southern constellation Centaurus on modern star charts. In fact, the new star was reported to be visible to the naked-eye for months before it faded from view, and is now thought to be the earliest recorded supernova. In this 21st century telescopic image, the wispy outlines of a faint emission nebula recognized as the remnant of that historical stellar explosion can be traced against a starry background. The ragged but roughly circular extent of the nebula, cataloged as RCW 86, represents interstellar gas ionized by the supernova’s 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 has accreted material from its 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.
來源:NASA每日圖片
