NASA每日一图 B.doc

NASA每日一图 A
蜘蛛星云附近的天区 
2008 April 26 
The Tarantula Zone 
Explanation: The Tarantula Nebula is more than 1,000 light-years in diameter -- a giant star forming region within our neighboring galaxy the Large Magellanic Cloud (LMC). That cosmic arachnid lies at the upper left of this expansive mosiac covering a part of the LMC over 6,000 light-years across. Within the Tarantula (NGC 2070), intense radiation, stellar winds and supernova shocks from the central young cluster of massive stars, cataloged as R136, energize the nebular glow and shape the spidery filaments. Around the Tarantula are other violent star-forming regions with young star clusters, filaments and bubble-shaped clouds. The small but expanding remnant of supernova 1987a, the closest supernova in modern history, is located near the center of the view. The rich field is about as wide as four full moons on the sky, located in the southern constellation Dorado.
影像版权与提供: Robert Gendler 
说明: 蜘蛛星云是邻近大麦哲伦星系(LMC)里的巨大恒星诞生区,其大小超过一千光年。在这张跨幅达六千光年的广大组合影像里,这只宇宙级节肢动物位在左上角。在蜘蛛星云(NGC 2070)之内,强烈的辐射、恒星风和中心年轻大质量恒星群(R136)的超新星爆炸震波,除了激发星云发出辉光之外,也雕塑出它酷似蜘蛛的丝缕状外观。蜘蛛星云附近还有其它很活跃的恒星形成区,它们都具有年轻星团、云气丝和泡泡状云气团等结构。近代历史上最邻近的超新星1987A,它小小但扩张中的遗骸就位在影像的中心附近。这幅含有众多天体的星场,位在剑鱼座,跨幅相当于四个满月的寛度(大约二度)。
M86星系群 
2008 April 25 
M86 in the Virgo Cluster 
Explanation: Bright lenticular galaxy M86 is near center of this cosmic view, at the heart of the Virgo Galaxy Cluster. Other bright galaxies in the neighborhood include M84 at the upper right, edge-on spiral NGC4388 near the right edge, a striking pair of interacting galaxies, Markarian's Eyes, in the lower left corner, and edge-on spiral NGC 4402 at about 11 o'clock. With well over a thousand members, the Virgo Cluster is the closest large cluster of galaxies. On average the cluster galaxies are measured to be about 50 million light-years away. The entire Virgo Cluster is difficult to appreciate because it covers such a large area, spanning over 10 degrees on the sky. This cluster close-up c