charles 2009-3-27 10:50
X光波劃觀測的克卜勒超新星殘骸
Kepler's Supernova Remnant in X-Rays
[img]http://i12.tinypic.com/4hsrny8.jpg[/img]
影像提供: NASA/CXC/NCSU/S. Reynolds et al.
[color=navy]Explanation: [/color]
[color=dimgray]What caused this mess? Some type of star exploded to create the unusually shaped nebula known as Kepler's supernova remnant, but which type? Light from the stellar explosion that created this energized cosmic cloud was first seen on planet Earth in October 1604, a mere four hundred years ago. The supernova produced a bright new star in early 17th century skies within the constellation Ophiuchus. It was studied by astronomer Johannes Kepler and his contemporaries, with out the benefit of a telescope, as they searched for an explanation of the heavenly apparition. Armed with a modern understanding of stellar evolution, early 21st century astronomers continue to explore the expanding debris cloud, but can now use orbiting space telescopes to survey Kepler's supernova remnant (SNR) across the spectrum. Recent X-ray data and images of Kepler's supernova remnant taken by the orbiting Chandra X-ray Observatory has shown relative elemental abundances more typical of a Type Ia supernova, indicating that the progenitor was a white dwarf star that exploded when it accreted too much material and went over Chandrasekhar's limit. About 13,000 light years away, Kepler's supernova represents the most recent stellar explosion seen to occur within our Milky Way galaxy. [/color]
[color=navy]說明:[/color]
[color=dimgray]這團東西是怎麼形成的？有些恆星爆炸後，就會產生像克卜勒超新星殘骸這種奇形怪狀的星雲，但它是哪個類型的？由這次恆星爆炸並形成充滿能量的宇宙雲時所發出來的光，在大約400年前，也就是西元1604年10月時抵達地球。這次超新星爆炸彷彿在17世紀蛇夫座的天空中誕生了一顆明亮的新星。天文學家克卜勒 (Johannes Kepler) 和他的伙伴利用現代的望遠鏡來解釋這種天空中的特異景像。利用現代的星球演化知識，21世紀的天文學家繼續探索這向外擴張的星塵雲，並利用太空望遠鏡對克卜勒超新星殘骸 (SNR) 進行多波段觀測。由錢卓拉X光望遠鏡觀測到最新的X光資料和影像顯示，它的元素豐度是屬於Ia 型超新星爆炸，這表示它是因為一顆白矮星經由吸積太多質量，使得質量超過錢卓極限之後所產生的超新星爆炸。克卜勒超新星殘骸距離我們約13,000光年，是銀河系中最近一次的超新星星爆炸。 [/color]
[size=2]資料來源: Scientific American
Department of Physics, NCKU[/size][color=white][size=1]
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