Thor's Helmet from CFHT
影像提供與版權: Jean-Charles Cuillandre (CFHT), Hawaiian Starlight, CFHT
Explanation:
NGC 2359 is a striking emission nebula with an impressive popular name - Thor's Helmet Sure, its suggestive winged appearance might lead some to refer to it as the "duck nebula", but if you were a nebula which name would you choose? By any name NGC 2359 is a bubble-like nebula some 30 light-years across, blown by energetic winds from an extremely hot star seen near the center and classified as a Wolf-Rayet star. Wolf-Rayet stars are rare massive blue giants which develop stellar winds with speeds of millions of kilometers per hour. Interactions with a nearby large molecular cloud are thought to have contributed to this nebula's more complex shape and curved bow-shock structures. NGC 2359 is about 15,000 light-years distant toward the constellation Canis Major.
說明:
NGC 2359 是一個醒目的發射星雲，它有另外一個響亮的名字 -- 雷神的頭盔。當然，有人會因為它有翼狀的側邊而認為它應該稱為"鴨子"星雲，不過如果你是個星雲，你會選擇哪個名字？不管NGC 2359 要用哪個名字，它是一個大小約 30 光年的泡泡狀星雲，是由中央有顆極高溫星球強烈的恆星風所吹出來的，這類星球是屬於沃夫-瑞葉型星。 沃夫-瑞葉型星是種罕見的大質量藍巨星，能吹出時速高達數百萬公里的恆星風。在恆星風和鄰近的巨大分子雲的交互作用之下，便產生了這個星雲複雜的外型和彎曲的弓狀震波結構。NGC 2359位於大犬座內，距離地球約15,000光年遠。
資料來源: Scientific American
Department of Physics, NCKU
