银河核心的恒星在抛出碳、氧
本帖最后由 gohomeman1 于 2009-4-28 12:05 编辑www.universetoday.com的新闻一天好多条，翻译实在费劲。这次选个短文吧，长文放在最后面。
http://www.universetoday.com/2009/03/12/stars-at-milky-way-core-exhale-carbon-oxygen/
Stars at Milky Way Core 'Exhale' Carbon, OxygenMarch 12th, 2009
Written by Anne Minard
Carbon and oxygen have been spotted in the dust around stars in the center of the Milky Way galaxy, suggesting that the stars have undergone recent disruptions of some kind — and hinting at a new way that stars can send heavy elements — like oxygen, carbon, and iron —out across the universe, paving the way for life.
在银河系核心区，C和O元素被恒星抛到它周围的尘埃盘中。（天文学家）推测这些恒星最近经历了一些爆发抛射过程，这暗示恒星在它们的生命历程中，向宇宙抛射重元素（比如C、O、Fe等）的一条新途径。
Scientists have long expected to find carbon-rich stars in our galaxy because we know that significant quantities of carbon must be created in many such stars. But carbon had not previously shown up in the clouds of gas around these stars, said Matthew Bobrowsky,an astrophysicist at the University of Maryland and a co-author of a new study reporting the discovery.
“我们知道，相当数量C元素由这些恒星制造的，科学家相当期待发现富C恒星。但是，以前我们并没有在这些恒星附近的气体云中发现（大量的）碳元素。”最新研究报告的作者、马里兰大学的天体物理学家Matthew Bobrowsky如是说。
“Based on our findings, this is because medium-sized stars rich in carbon sometimes keep that carbon hidden until very near the end of their stellar lives, releasing it only with their final ‘exhalations’,” explained Bobrowsky.
Bobrowsky解释说：“根据我们的观察，这是因为中尺度的恒星持续富集C元素直到它们的生命末期，（向宇宙抛射）C元素仅仅在它们的最后“喷发期””。
PS：最后喷发期就是新星爆发嘛！不过这不是恒星的最后生命期吧。在银河核心区，由于恒星密集，白矮星还可能通过吸积外部物质从而发生Ia级超新星爆发，并把整个恒星全部炸碎抛射到宇宙中，但我们太阳系不会这样的。
disruption原词没有抛射含义，我想这样的翻译大家容易理解，因为从没听说恒星分裂的。本文中行星状星云的遥远外层区域不是由大规模爆发产生，而是红巨星阶段逐步抛掉外层气壳形成的。全文的中心论述点就是在这些外层中发现了C、O等元素，而且丰度远远超过了普通星云中的含量。——gohomeman1
http://www.universetoday.com/wp-content/uploads/2009/03/cats-eye1.jpg 本帖最后由 gohomeman1 于 2009-4-28 11:48 编辑
奇怪，他引用的图是这张，但spitzer中的文字好像不一样啊？
NASA/JPL-Caltech/J. Hora (Harvard-Smithsonian CfA)
'Cat's Eye' Planetary Nebula
The "Cat's Eye" nebula, or NGC 6543, is a well-studied example of a"planetary nebula." Such objects are the glowing remnants of dust and gas expelled from moderate-sized stars during their last stages oflife. Our own sun will generate such a nebula in about five billionyears.
NGC 6543,俗称“猫眼”星云，是研究“行星状星云”的一个范本。当中等质量的恒星走到它们生命的末期时，就会逐步抛出这样一个由气体、尘埃组成的炽热外壳残余。我们的太阳在50亿年后就会产生这样的星云。
NASA's Spitzer Space Telescope has studied many such planetary nebulaein infrared light, including a variety of more distant ones, which have helped scientists identify a population of carbon-bearing stars near our galaxy's center.
Spitzer太空望远镜已经研究了大量的此类行星状星云的红外辐射，包括非常遥远的各种类型，这有助于科学家标识我们银河系核心附近的含碳恒星的数量、比例。
The infrared emission from the Cat's Eye is generated by a variety of elements and molecules. The bright inner region of this nebula shows a complex structure reminiscent of a feline eye. Outside this compact region lies a series of other structures representing material that was ejected slightly earlier in the central star's life, when it was agiant star.
猫眼星云的红外辐射由各种分子和原子产生。明亮的内部区域显示出一个猫眼的复合结构（我们常见的猫眼可见光图像区域），这个紧密结构的外部则是一系列不同的结构（图中的蓝、绿色区域——译者注），表示外部的物质是中央恒星在它早期的红巨星阶段轻微抛射出来的。
The image is a composite of data from Spitzer's infrared array camera.Light with a wavelength of 3.6 microns is rendered as blue, 5.8 micronsis displayed as green and 8.0 microns is represented in red. The brightness of the central area has been greatly reduced to make itpossible to maintain its visibility while enhancing the brightness ofthe much fainter outer features. Overall colors have been enhanced to better show slight variations in hue.
本图是Spitzer的红外阵列相机数据组合的伪彩色图，蓝——3.6微米波段，绿——5.8微米，红——8.0微米。明亮的中央区域已经被大幅度消光以便显示外部区域（早期喷发物）微弱的细节。色彩、色调已经增强，以便更好的显示变化情况。
PS：其实猫眼星云论坛中有好多帖子，本文说的是外部那些一般情况下不明显的早期喷发物。猫眼星云的索引帖：
http://www.astronomy.com.cn/bbs/viewthread.php?tid=106987&extra=&highlight=&page=13第251#楼
http://ipac.jpl.nasa.gov/media_images/sig09-001_Sm.jpg 本帖最后由 gohomeman1 于 2009-3-27 15:10 编辑
图像方面的信息
About the Object (1)Object name:Cat's Eye, NGC 6543Object type:NebulaPosition (J2000):RA: 17h 58m 33.42sDec: 66° 37' 59.52"Distance:3300 Light YearsConstellation:Draco About the Data Spitzer Data Image Credit:NASA/JPL-Caltech/J. Hora (Harvard-Smithsonian CfA)Instrument:IRACWavelength:3.6 Micron (Blue), 5.8 Micron (Green), 8.0 Micron (Red)Release Date:2009/03/12 Additional Info Related links:Galactic Dust Bunnies Found to Contain Carbon After All
大图链接
http://ipac.jpl.nasa.gov/media_images/sig09-001.jpg
http://ipac.jpl.nasa.gov/media_images/sig09-001.jpg
本帖最后由 gohomeman1 于 2010-11-24 12:31 编辑
http://www.universetoday.com/2009/03/12/stars-at-milky-way-core-exhale-carbon-oxygen/
Stars at Milky Way Core 'Exhale' Carbon, Oxygen
银河系核心区的恒星“呼出”碳、氧
March 12th, 2009，Written by Anne Minard
作者安妮.Minard，写于2009.3.12
Carbon and oxygen have been spotted in the dust around stars in the center of the Milky Way galaxy, suggesting that the stars have undergone recent disruptions of some kind — and hinting at a new way that stars can send heavy elements— like oxygen, carbon, and iron — out across the universe, paving the way for life.
在银河系核心区，碳（C）和氧（O）元素被恒星抛到它周围的尘埃云中。天文学家推测它们最近经历了一系列的瓦解过程，这暗示着恒星向宇宙抛射重元素（比如C、O、Fe等）的一条新途径，为生命形成铺平道路。
Scientists have long expected to find carbon-rich stars in ourgalaxy because we know that significant quantities of carbon must be created in many such stars. But carbon had not previously shown up in the clouds of gas around these stars, said Matthew Bobrowsky, an astrophysicist at the University of Maryland and a co-author of a new study reporting the discovery.
长期以来，科学家都很期待在银河系内发现富碳恒星，因为我们知道大量的C元素是它们制造的。但是，新研究报告的联合作者、马里兰大学天体物理学家Matthew Bobrowsky 说：“以前我们并没有在这些恒星附近的气体云中发现（大量的）碳元素。”
“Based on our findings, this is because medium-sized stars rich in carbon sometimes keep that carbon hidden until very near the end of their stellar lives, releasing it only with their final ‘exhalations’,” explained Bobrowsky.
Bobrowsky继续说：“根据我们的观测，这是因为中等尺度的恒星（比如太阳——译注）持续富集C元素直到它们的生命末期，仅在它们的最后'喘息'时才释出碳。”
The new results appear in the February issue of the journal Astronomy and Astrophysics.
新研究报告发表在2009.2月的《天文学与天体物理学》期刊上。
Bobrowsky and his team, led by J. V. Perea-Calderón at the EuropeanSpace Astronomy Centre in Madrid, Spain, used the Spitzer Space Telescope to view each star and its surrounding clouds of dust and particles, called a planetary nebulae. The researchers measured the light emitted by the stars and the surrounding dust and were able to identify carbon compounds based on the wavelengths of light emitted by the stars. Looking in an area at the center of the Milky Way called the“Galactic Bulge,” the team observed 26 stars and their planetary nebulae and found 21 with carbon “signatures.”
Bobrowsky和他的团队，由位于西班牙马德里的欧洲天文学中心的J. V. Perea-Calderón牵头（关系好复杂的说——译注），使用Spitzer红外空间望远镜观测了多个带有行星状星云的恒星（这些星云由气体尘埃等组成，貌似废话）。 研究人员测量恒星和它的尘埃环的光谱，从而把碳化合物谱线从恒星的光谱线中分辨出来。在银河中心的“星系核球区”，研究人员研究了26个恒星和它们的行星状星云，发现其中的21个带有碳“签名”。
But the scientists did not just find carbon around these stars;they also found oxygen in these 21 dust clouds, revealing a surprising mixture of ingredients for space dust. They report in their paper that this is likely due to a thermal pulse where a wave of high-pressure gas mixes layers of elements like carbon and oxygen and spews them out into the surrounding cloud.
科学家不仅发现了C，他们还在21个尘埃环中都发现了O，惊讶于发现太空尘埃就像拌和的饲料一样。在报告中，他们解释说这可能是因为高压气体产生的热脉冲波把各层的C、O元素混合在一起并喷发到周围的气体云。
The finding of carbon and oxygen in the dust clouds surrounding stars suggests a recent change of chemistry in this population of stars, according to the authors.
根据作者的看法，在行星状星云中发现C、O的事实将对此类恒星的化学组成产生新的改变。
“Stars in the center of the Milky Way are old and ‘metal-rich’ with a high abundance of heavy elements,” Bobrowsky said. “They are different in chemical composition than those found in the disc, farther out from the center.”
Bobrowsky解释道：“银河中心的恒星都比较古老，是‘富金属’星，重元素丰度很高。它们与远离核心区的银盘上的恒星的化学组成很不一样。”
Studying the chemistry of the stars helps scientists learn how the matter that makes up our earth and other planets in our galaxy left its stellar birth places long ago.
研究恒星的化学组成有助于科学家了解组成我们地球和其他行星的物质，很久以前是怎样离开恒星诞生地的。
As a star burns hotter and hotter, the hydrogen gas that originally made up almost all of its mass is converted, through nuclearfusion, first to helium, and then to progressively heavier elements.The hottest region in the core fuses together the heaviest elements. And these can reach the surface of the star only when its life is almost over.
随着恒星演化，它的核心越来越热，最初几乎全部由氢（H）组成的物质将逐步聚变。通过热核反应，开始是氦（He），接着是更重的元素。恒星最热的核心区进行最重元素的融合。只有当恒星生命将结束时，重元素才能抵达恒星表面。（太阳这样的恒星最多能进行3He聚变为C的反应和C+He=O+2v（简化式）的反应，更多重元素需要大质量恒星——译注）
“The Big Bang produced only hydrogen and helium,” Bobrowsky said. “Heavier elements like carbon and oxygen only come from getting ‘cooked up’ in stars. Nuclear reactions in stars created the heavier elements found in ‘life as we know it’.”
Bobrowsky说：“宇宙大爆炸后只形成了H和He，更重的元素像C、O等只能在恒星熔炉中锻造。热核反应创造的重元素构成了'我们所知道的生命'。”（一首重金属摇滚歌曲，这是双关语——gohomeman1注）
In the last 50,000 years of their 10 billion-year lives,sun-sized stars expel carbon atoms along with hydrogen and helium to form a surrounding cloud of gas that soon disperses into space, perhaps to eventually become the stuff of new stars, solar systems, or perhaps even life on some earth-like planet. Much larger stars expel their heavier matter in massive explosions called supernovae.
在类太阳恒星100亿年生命的最后5万年期间，C和H、He等一起被恒星驱离并形成周围的气体云，然后迅速消散在宇宙空间中。这些物质可能最后形成了新的恒星、太阳系，还可能形成像我们地球这样的行星。大质量恒星（一般指10个太阳质量以上）通过巨大的超新星爆发抛射它们的重元素。
“All the heavy elements on Earth were created by nuclear fusion reactions in previous generations of stars,”said Bobrowsky. “Those earlier stars expelled those elements into space and then our solar system formed out of that gas containing all the heavy elements that we now find in Earth and in life on Earth.”
Bobrowsky总结道：“地球上的所有重元素都是N世代以前其他恒星的热核反应产生的，早期恒星制造并抛射重元素到太空中。我们的太阳系就从包含各种重元素的气体云中形成，而今，这些重元素在地球上和我们的生命中”。（注：天文学家所说的“金属”指所有原子序数大于He的元素）
LEAD IMAGE CAPTION: Cat's Eye Nebula.
题头图片：猫眼星云 NGC 6543
Credit: NASA/JPL-Caltech/J. Hora (Harvard-SmithsonianCfA)
版权：美国宇航局（NASA），加州理工学院、喷气推进实验室（JPL），哈佛—史密松天体物理中心（CfA）J. Hora
Source: Astronomy & Astrophysics and Spitzer, via AAS
原文来源：《天文学与天体物理学》网站、斯必泽红外卫星网站、美国天文学会网站 嘿嘿，多翻译翻译貌似英语单词水平有所提高了。一眼就看懂的那句直接翻译了，不查字典了。 1# gohomeman1
此段感觉不太达意。
另外，最后的"stellar lives"译成主序星阶段就行了嘛，相信作者肯定是这个意思。 1# gohomeman1
此段感觉不太达意。
另外，最后的"stellar lives"译成主序星阶段就行了嘛，相信作者肯定是这个意思。
positron 发表于 2009-4-28 10:38 http://www.astronomy.com.cn/bbs/images/common/back.gif
谢谢版主一个个仔细的检查。最初一些翻译确实质量不行，现在翻译了好多，如果不是别人去细看，自己不太可能再一个个去回顾问题了。
不过，主序星英文一般都写为Main-Sequence Star，而这些作者的恒星生命末期一般都是指新星、超新星爆发。他不写这个词，我不好这样翻译。
再次感谢！ 稍微修改了一下，但是主序星阶段这个词我没改，全文总体看，没有提到中等恒星能在主序星阶段把重元素扩散到宇宙去，而是说在红巨星阶段就在扩散C、O元素了，如此就算不会经历新星爆发的恒星，也能把部分重元素散布到宇宙中。 漩涡星系的相比喷出的应该更多。如M87 当年的翻译不是一般的差，今天重新修正了主要的内容，并且补充一张对比图吧：
这是哈勃ACS拍摄的猫眼星云中心图，摄于2002.5.4 贼牛叉 顶顶 11楼的图片真漂亮！！！ 哈哈 又知道一个好的网站 多去看看 好得很
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