charles 2009-3-23 11:37
獵戶座星雲周圍的巴納德環
Barnard's Loop around the Horsehead Nebula
[img]http://i15.tinypic.com/473jif7.jpg[/img]
影像版權與提供: Peter Erdman (Embry-Riddle U.)
[color=navy]Explanation:[/color]
[color=dimgray]Why is the Horsehead Nebula surrounded by a bubble? Although glowing like an emission nebula, the origin of the bubble, known as Barnard's Loop, is currently unknown. Progenitor hypotheses include the winds from bright Orion stars and the supernovas of stars long gone. Barnard's Loop is too faint to be identified with the unaided eye. The nebula was discovered only in 1895 by E. E. Barnard on long duration film exposures. The above image was taken in a single specific color emitted by hydrogen to bring out detail. To the left of the Horsehead Nebula, visible as the small dark indentation near the image top, is the photogenic Flame Nebula. [/color]
[color=navy]說明:[/color]
[color=dimgray]為什麼獵戶座馬頭星雲周圍環繞一 個泡泡？這個被稱為巴納德環 (Barnard's Loop)的泡泡雖然像發射星雲一樣會發出輝光，但它的起因卻仍是未知。起源假設包括是由獵戶座亮星的恆星風及早已消失的超新星爆炸。太暗而肉眼不得見的巴納德環，是直到1895年才由巴納德在長時間曝光底片上發現了。上面這幅影像是透過特定的氫輻射波段所拍攝的影像，以帶出細部的結構。馬頭星雲的左方，靠近影像頂的小型淡色斑塊就是很上鏡頭的火焰星雲。(馬頭星雲 -- Horsehead Nebula; 巴納德 -- E. E. Barnard; 巴納德環 -- Barnard's Loop; 火焰星雲 -- Flame Nebula)[/color]
[size=2]資料來源: Scientific American
Department of Physics, NCKU[/size][color=white][size=1]
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