Gum 19恒星形成星云的亮面与暗面
文章来源:未知 文章作者:meng 发布时间:2010-04-01 02:56 字体: [ ]  进入论坛
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Gum 19 is located in the direction of the constellation1(星座,荟萃) Vela (the Sail) at a distance of approximately 22 000 light years. The Gum 19 moniker(绰号,名字) derives2 from(源于,来自) a 1955 publication by the Australian astrophysicist(天体物理学家) Colin S. Gum that served as the first significant survey of so-called HII (read "H-two") regions in the southern sky. HII refers to hydrogen gas that is ionised(电离) , or energised(供给……能量) to the extent that the hydrogen atoms lose their electrons(电子) . Such regions emit light at well-defined wavelengths3 (or colours), thereby4 giving these cosmic clouds their characteristic glow. And indeed, much like terrestrial(陆地的,陆生的) clouds, the shapes and textures5 of these HII regions change as time passes, though over the course of eons(万古,永世) rather than before our eyes. For now, Gum 19 has somewhat of a science fiction-esque(似……的) , "rip in spacetime" look to it in this image, with a narrow, near-vertical bright region slashing6 across the nebula7(星云) . Looking at it, you could possibly see a resemblance to a two-toned angelfish(扁鲨,神仙鱼) or an arrow with a darkened point. This new image of the evocative(唤起的) Gum 19 object was captured by an infrared8 instrument called SOFI, mounted on ESO's New Technology Telescope (NTT) that operates at the La Silla Observatory9 in Chile. SOFI stands for Son of ISAAC, after the "father" instrument, ISAAC, that is located at ESO's Very Large Telescope observatory at Paranal to the north of La Silla. Observing this nebula in the infrared allows astronomers10 to see through at least parts of the dust.

The furnace(火炉,熔炉) that fuels Gum 19's luminosity(光度,光辉) is a gigantic, superhot star called V391 Velorum. Shining brightest in the scorching11(灼热的,激烈的) blue range of visible light, V391 Velorum boasts a surface temperature in the vicinity of 30 000 degrees Celsius12. This massive star has a temperamental nature, however, and is categorised as a variable star accordingly. V391 Velorum's brightness can fluctuate(动摇,波动) suddenly as a result of strong activity that can include ejections of shells of matter, which contribute to Gum 19's composition and light emissions13.

Stars on the grand scale of V391 Velorum do not burn bright for long, and after a relatively14 short lifetime of about ten million years these titans blow up as supernovae(超新星) . These explosions, which temporarily rival whole galaxies15 in their light intensity16, blast heated matter in surrounding space, an event that can radically17 change the colour and shape of its enclosing(封闭,围合) nebula. As such, V391 Velorum's death throes may well leave Gum 19 unrecognisable.

Within the neighbourhood of this fitful supergiant, new stars nonetheless continue to grow. HII regions denote sites of active star formation wherein great quantities of gas and dust have begun to collapse18 under their own gravity. In several million years — a blink of an eye in cosmic time — these shrinking knots of matter will eventually reach the high density19 at their centres necessary to ignite(点燃,燃烧) nuclear fusion20. The fresh outpouring(流露,流出) of energy and stellar winds(恒星风) from these newborn stars will also modify the gaseous21 landscape of Gum 19.



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1 constellation CptzI     
n.星座n.灿烂的一群
参考例句:
  • A constellation is a pattern of stars as seen from the earth. 一个星座只是从地球上看到的某些恒星的一种样子。
  • The Big Dipper is not by itself a constellation. 北斗七星本身不是一个星座。
2 derives c6c3177a6f731a3d743ccd3c53f3f460     
v.得到( derive的第三人称单数 );(从…中)得到获得;源于;(从…中)提取
参考例句:
  • English derives in the main from the common Germanic stock. 英语主要源于日耳曼语系。 来自《简明英汉词典》
  • He derives his income from freelance work. 他以自由职业获取收入。 来自《简明英汉词典》
3 wavelengths 55c7c1db2849f4af018e7824d42c3ff2     
n.波长( wavelength的名词复数 );具有相同的/不同的思路;合拍;不合拍
参考例句:
  • I find him difficult to talk to—we're on completely different wavelengths. 我没法和他谈话,因为我们俩完全不对路。 来自《简明英汉词典》
  • Sunlight consists of different wavelengths of radiation. 阳光由几种不同波长的射线组成。 来自辞典例句
4 thereby Sokwv     
adv.因此,从而
参考例句:
  • I have never been to that city,,ereby I don't know much about it.我从未去过那座城市,因此对它不怎么熟悉。
  • He became a British citizen,thereby gaining the right to vote.他成了英国公民,因而得到了投票权。
5 textures c5e62798e528da9080811018cbb27cd3     
n.手感( texture的名词复数 );质感;口感;(音乐或文学的)谐和统一感
参考例句:
  • I'm crazy about fabrics textures and colors and designs. 我喜欢各式各样的纺织物--对它的质地,色彩到花纹图案--简直是入了迷。 来自辞典例句
  • Let me clear up the point about the textures. 让我明确了一点有关的纹理。 来自互联网
6 slashing dfc956bca8fba6bcb04372bf8fc09010     
adj.尖锐的;苛刻的;鲜明的;乱砍的v.挥砍( slash的现在分词 );鞭打;割破;削减
参考例句:
  • Slashing is the first process in which liquid treatment is involved. 浆纱是液处理的第一过程。 来自辞典例句
  • He stopped slashing his horse. 他住了手,不去鞭打他的马了。 来自辞典例句
7 nebula E55zw     
n.星云,喷雾剂
参考例句:
  • A powerful telescope can resolve a nebula into stars.一架高性能的望远镜能从星云中分辨出星球来。
  • A nebula is really a discrete mass of innumerous stars.一团星云实际上是无数星体不连续的集合体。
8 infrared dx0yp     
adj./n.红外线(的)
参考例句:
  • Infrared is widely used in industry and medical science.红外线广泛应用于工业和医学科学。
  • Infrared radiation has wavelengths longer than those of visible light.红外辐射的波长比可见光的波长长。
9 observatory hRgzP     
n.天文台,气象台,瞭望台,观测台
参考例句:
  • Guy's house was close to the observatory.盖伊的房子离天文台很近。
  • Officials from Greenwich Observatory have the clock checked twice a day.格林威治天文台的职员们每天对大钟检查两次。
10 astronomers 569155f16962e086bd7de77deceefcbd     
n.天文学者,天文学家( astronomer的名词复数 )
参考例句:
  • Astronomers can accurately foretell the date,time,and length of future eclipses. 天文学家能精确地预告未来日食月食的日期、时刻和时长。 来自《简明英汉词典》
  • Astronomers used to ask why only Saturn has rings. 天文学家们过去一直感到奇怪,为什么只有土星有光环。 来自《简明英汉词典》
11 scorching xjqzPr     
adj. 灼热的
参考例句:
  • a scorching, pitiless sun 灼热的骄阳
  • a scorching critique of the government's economic policy 对政府经济政策的严厉批评
12 Celsius AXRzl     
adj.摄氏温度计的,摄氏的
参考例句:
  • The temperature tonight will fall to seven degrees Celsius.今晚气温将下降到七摄氏度。
  • The maximum temperature in July may be 36 degrees Celsius.七月份最高温度可能达到36摄氏度。
13 emissions 1a87f8769eb755734e056efecb5e2da9     
排放物( emission的名词复数 ); 散发物(尤指气体)
参考例句:
  • Most scientists accept that climate change is linked to carbon emissions. 大多数科学家都相信气候变化与排放的含碳气体有关。
  • Dangerous emissions radiate from plutonium. 危险的辐射物从钚放散出来。
14 relatively bkqzS3     
adv.比较...地,相对地
参考例句:
  • The rabbit is a relatively recent introduction in Australia.兔子是相对较新引入澳大利亚的物种。
  • The operation was relatively painless.手术相对来说不痛。
15 galaxies fa8833b92b82bcb88ee3b3d7644caf77     
星系( galaxy的名词复数 ); 银河系; 一群(杰出或著名的人物)
参考例句:
  • Quasars are the highly energetic cores of distant galaxies. 类星体是遥远星系的极为活跃的核心体。
  • We still don't know how many galaxies there are in the universe. 我们还不知道宇宙中有多少个星系。
16 intensity 45Ixd     
n.强烈,剧烈;强度;烈度
参考例句:
  • I didn't realize the intensity of people's feelings on this issue.我没有意识到这一问题能引起群情激奋。
  • The strike is growing in intensity.罢工日益加剧。
17 radically ITQxu     
ad.根本地,本质地
参考例句:
  • I think we may have to rethink our policies fairly radically. 我认为我们可能要对我们的政策进行根本的反思。
  • The health service must be radically reformed. 公共医疗卫生服务必须进行彻底改革。
18 collapse aWvyE     
vi.累倒;昏倒;倒塌;塌陷
参考例句:
  • The country's economy is on the verge of collapse.国家的经济已到了崩溃的边缘。
  • The engineer made a complete diagnosis of the bridge's collapse.工程师对桥的倒塌做了一次彻底的调查分析。
19 density rOdzZ     
n.密集,密度,浓度
参考例句:
  • The population density of that country is 685 per square mile.那个国家的人口密度为每平方英里685人。
  • The region has a very high population density.该地区的人口密度很高。
20 fusion HfDz5     
n.溶化;熔解;熔化状态,熔和;熔接
参考例句:
  • Brass is formed by the fusion of copper and zinc. 黄铜是通过铜和锌的熔合而成的。
  • This alloy is formed by the fusion of two types of metal.这种合金是用两种金属熔合而成的。
21 gaseous Hlvy2     
adj.气体的,气态的
参考例句:
  • Air whether in the gaseous or liquid state is a fluid.空气,无论是气态的或是液态的,都是一种流体。
  • Freon exists both in liquid and gaseous states.氟利昂有液态和气态两种形态。
TAG标签: light gas star bright
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