大麦哲伦星系的星云
影像来源与版权:Team Ciel Austral –
J. C. Canonne, N. Outters, P. Bernhard, D. Chaplain, L. Bourgon

说明:大麦哲伦星系(LMC)是南天一个很吸睛的天体。而这幅细致、费时超过10个月才完成的望远镜长曝光影像,呈现了地球大多数的环球航行者难以见到的景观。这幅由4×4个版面组合成的,视野涵盖超过5度天区(10个满月)的影像,建构自总曝光分时间1,060小时,并透过宽与窄波段滤镜拍摄的3,900照片。其中的窄波段滤镜,只有硫、氢和氧原子辐射出的光才能透过。被高能星光电离的这些原子,在重新捕获失去的电子跃迁到较低能态的过程中,会辐射出该原子特有的特征色光。因此在这张影像里,大麦哲伦星系看似到处都是包裹在大质量年轻恒星周围的电离气体云。在强烈恒星风和紫外辐射的雕塑下,这些明亮星云最主宰性的辐射是氢原子发出的光,故它们亦称为H II(电离氢)区。位在影像左侧名为蜘蛛星云的大形恒星形成区,基本上是由许多HII区叠成的天体。位在剑鱼座方向,宽约15,000光年,距离近在160,000光年之处的大麦哲伦星系,是我们银河系最大的伴星系。
翻译:“每日一天文图”成大物理分站

Clouds of the Large Magellanic Cloud
Image Credit & Copyright: Team Ciel Austral –
J. C. Canonne, N. Outters, P. Bernhard, D. Chaplain, L. Bourgon

Explanation: The Large Magellanic Cloud (LMC) is an alluring sight in southern skies. But this deep and detailed telescopic view, over 10 months in the making, goes beyond what is visible to most circumnavigators of planet Earth. Spanning over 5 degrees or 10 full moons, the 4×4 panel mosaic was constructed from 3900 frames with a total of 1,060 hours of exposure time in both broadband and narrowband filters. The narrowband filters are designed to transmit only light emitted by sulfur, hydrogen, and oxygen atoms. Ionized by energetic starlight, the atoms emit their characteristic light as electrons are recaptured and the atoms transition to a lower energy state. As a result, in this image the LMC seems covered with its own clouds of ionized gas surrounding its massive, young stars. Sculpted by the strong stellar winds and ultraviolet radiation, the glowing clouds, dominated by emission from hydrogen, are known as H II (ionized hydrogen) regions. Itself composed of many overlapping H II regions, the Tarantula Nebula is the large star forming region at the left. The largest satellite of our Milky Way Galaxy, the LMC is about 15,000 light-years across and lies a mere 160,000 light-years away toward the constellation Dorado.
Astronomy Picture of the Day 05/03/2019