ESO091111:研究太阳内部化学元素之系外行星法
本帖最后由 其祥 于 2009-11-13 22:52 编辑我也努力地尝试一下翻译。O(∩_∩)O，希望大家不吝赐教，有翻译不当之处给予意见和建议，谢谢。内容与版面设计参考借鉴并学习gohomeman1 兄。
http://www.eso.org/public/outreach/press-rel/pr-2009/pr-42-09.html
ESO 42/09 - Science Release
11 November 2009
For immediate release
ESO科学报告2009年度第42#，2009.11.11即时公布。
Exoplanets Clue to Sun's Curious Chemistry
通过系外行星研究太阳内部化学元素
A ground-breaking census of 500 stars, 70 of which are known to host planets, has successfully linked the long-standing “lithium mystery” observed in the Sun to the presence of planetary systems. Using ESO’s successful HARPS spectrograph, a team of astronomers has found that Sun-like stars that host planets have destroyed their lithium much more efficiently than “planet-free” stars. This finding does not only shed light on the lack of lithium in our star, but also provides astronomers with a very efficient way of finding stars with planetary systems.
一项对500颗恒星（它们中的70个含有行星系统）所进行的具有开创性意义的统计，成功地将长期存在的“锂谜团”事件与太阳本身含有行星系统联系在一起。通过利用欧洲南方天文台的“行星搜索器"，一个天文学家小组发现类似太阳（有行星绕转）的恒星相比“无行星”系统的恒星更快地将锂燃烧掉。这一发现不仅阐明了为何太阳中缺乏锂，而且也为天文学家们提供了一个用来搜寻系外行星系统（类似太阳系）非常行之有效的方法。
（其祥注：HARPS---High Accuracy Radial Velocity Planet Searcher高精度视向速度行星搜索器） 本帖最后由 其祥 于 2009-11-14 12:35 编辑
“For almost 10 years we have tried to find out what distinguishes stars with planetary systems from their barren cousins,” says Garik Israelian, lead author of a paper appearing this week in the journal Nature. “We have now found that the amount of lithium in Sun-like stars depends on whether or not they have planets.”
这周在《自然》杂志上以第一作者身份发表论文的Garik Israelian说，近大约10年来，我们一直在试图寻找”有行星“恒星系统与”无行星“恒星系统之间的差别。现在，我们已经发现”类太阳“恒星内部所含锂的多少与它本身是否有行星绕转有关。
Low levels of this chemical element have been noticed for decades in the Sun, as compared to other solar-like stars, and astronomers have been unable to explain the anomaly. The discovery of a trend among planet-bearing stars provides a natural explanation to this long-standing mystery. “The explanation of this 60 year-long puzzle is for us rather simple,” adds Israelian. “The Sun lacks lithium because it has planets.”
Israelian说，几十年来，相比其他”类太阳“恒星，天文学家一直无法解释为何太阳中锂的含量会如此之低。”有行星“恒星系统的演化过程为长期困惑科学家们的”锂谜团“事件提供了一种很自然地解释。他又说，”对于大约已经持续60年的困惑的解释简单之极---太阳缺锂，因为它有行星绕转。“
This conclusion is based on the analysis of 500 stars, including 70 planet-hosting stars. Most of these stars were monitored for several years with ESO’s High Accuracy Radial Velocity Planet Searcher. This spectrograph, better known as HARPS, is attached to ESO's 3.6-metre telescope and is the world’s foremost exoplanet hunter. “This is the best possible sample available to date to understand what makes planet-bearing stars unique,” says co-author Michel Mayor.
此结论建立在对500颗恒星（其中的70颗恒星为”有行星“系统）样本进行分析的基础上。这些恒星已被安装在欧洲南方天文台3.6米天文望远镜上世界最著名的行星猎手----HARPS观测了很长一段时间。论文的第二作者Michel Mayor说，”到目前为止，对于理解”有行星“恒星系统的独特性，这可能是可利用的最好样本“
The astronomers looked in particular at Sun-like stars, almost a quarter of the whole sample. They found that the majority of stars hosting planets possess less than 1% of the amount of lithium shown by most of the other stars. “Like our Sun, these stars have been very efficient at destroying the lithium they inherited at birth,” says team member Nuno Santos. “Using our unique, large sample, we can also prove that the reason
for this lithium reduction is not related to any other property of the star, such as its age.”
天文学家们尤其对于占据总样本容量1/4的”类太阳“恒星进行了分析。他们发现其中的大多数”有行星“恒星系统相比于”无行星“恒星系统仅仅含有不到1%的锂。项目成员Nuno Santos说，”像太阳一样，此类恒星自诞生之日燃烧锂的速度非常快。通过对这批大容量且具独特性的样本分析后，我们也可以说明锂的递减和恒星的固有性质（比如其年龄）无关“
Unlike most other elements lighter than iron, the light nuclei of lithium, beryllium and boron are not produced in significant amounts in stars. Instead, it is thought that lithium, composed of just three protons and four neutrons, was mainly produced just after the Big Bang, 13.7 billion years ago. Most stars will thus have the same amount of lithium, unless this element has been destroyed inside the star.
不同于大多数比铁轻的元素，Li、Be、B等轻元素大部分不是在恒星内制造的。相反，仅由三个质子和四个中子构成的锂主要出现在137亿年之前的大爆炸之后。于是，除非它自己被燃烧掉，大部分恒星都含有的差不多的锂。
This result also provides the astronomers with a new, cost-effective way to search for planetary systems: by checking the amount of lithium present in a star astronomers can decide which stars are worthy of further significant observing efforts.
这个结果也为科学家们提供了一种新的而且划算的搜索行星系统的方法：通过核算目前恒星中锂的含量，科学家可以做出哪些恒星值得进一步的观察的决定。
Now that a link between the presence of planets and curiously low levels of lithium has been established, the physical mechanism behind it has to be investigated. “There are several ways in which a planet can disturb the internal motions of matter in its host star, thereby rearrange the distribution of the various chemical elements and possibly cause the destruction of lithium. It is now up to the theoreticians to figure out which one is the most likely to happen,” concludes Mayor.
既然恒星中微量的锂和它本身含有行星绕转二者相互关联，它所蕴含的物理机制也会被研究。Mayor最后说，”一个行星可以在若干方面上影响其主星内部物质的运动，因此，就存在各种元素含量重新分配的可能性，这也可能导致了恒星中锂元素的减少。到目前为止，理论学家们在试图弄清楚究竟哪一种可能性占主导地位“。 本帖最后由 其祥 于 2009-11-14 00:47 编辑
More Information
更多信息
This research was presented in a paper that appears in the 12 November 2009 issue of Nature (Enhanced lithium depletion in Sun-like stars with orbiting planets, by G. Israelian et al.).
这项研究发表在2009年11月12日的《自然》杂志上：”对于含有行星绕转的类太阳恒星系统中锂损耗的研究”，作者G. Israelian等。
The team is composed of Garik Israelian, Elisa Delgado Mena, Carolina Domínguez Cerdeña, and Rafael Rebolo (Instituto de Astrofisíca de Canarias, La Laguna, Tenerife, Spain), Nuno Santos and Sergio Sousa (Centro de Astrofisica, Universidade de Porto, Portugal), Michel Mayor and Stéphane Udry (Observatoire de Genève, Switzerland), and Sofia Randich (INAF, Osservatorio di Arcetri, Firenze, Italy).
团队成员：
西班牙， 特纳利夫岛，拉拉古纳，加那利群岛天文研究院：Elisa Delgado Mena, Carolina Domínguez Cerdeña, Rafael Rebolo
葡萄牙，波尔图大学，空间研究中心：Nuno Santos，Sergio Sousa
瑞士，日内瓦天文台：Michel Mayor，Stéphane Udry
意大利，佛罗伦萨，阿萨特里观测站，天体物理研究所：Sofia Randich
ESO, the European Southern Observatory, is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive astronomical observatory. It is supported by 14 countries: Austria, Belgium, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Portugal, Spain, Sweden, Switzerland and the United Kingdom. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world’s most advanced visible-light astronomical observatory. ESO is the European partner of a revolutionary astronomical telescope ALMA, the largest astronomical project in existence. ESO is currently planning a 42-metre European Extremely Large optical/near-infrared Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.
ESO，欧洲南方天文台,它是欧洲著名的天文合作组织，也是世界上最有成效的天文台之一。它得到了14个国家的支持：奥地利，比利时，捷克共和国，丹麦，法国，芬兰，德国，意大利，荷兰，葡萄牙，西班牙，瑞典，瑞士和英国。欧洲南方天文台致力于设计、建设、运作强大的地基观测设施，它所进行的宏伟计划，使天文学家取得了重要的科学发现。ESO也在促进和进行天文研究方面的合作发挥了积极地主导作用。ESO所占据三个世界级的观测地点都在智利：拉西拉，帕瑞纳和查南托。在帕拉那山，是世界上最顶级的可见光天文台---ESO甚大望远镜。同时，ESO也是欧洲合作伙伴具有划时代意义的最大天文项目的所在地。此外，ESO目前正在规划的42米欧洲极大光学/近红外线望远镜（缩写为E-ELT）,将成为“遥望天空中世界上最大的眼睛”。 本帖最后由 其祥 于 2009-11-14 14:06 编辑
Links
链接
Research paper （pdf文件，可以下载）
研究论文
More info: Exoplanet Media Kit （pdf文件，可以下载。大小：1.11M）
更多信息：系外行星探索系列
Project page of G. Israelian : http://www.iac.es/proyecto/abuntest/framesetwelcome.htm
G. Israelian 的项目首页
ESO press release 10/01
ESO新闻稿
附图一：环绕HD69830的行星系统（艺术想象图） 本帖最后由 其祥 于 2009-11-14 14:10 编辑
Contacts
联系方式
Garik Israelian
Insitituto de Astrofisica de Canarias, Tenerife, Spain
西班牙， 特纳利夫岛，拉拉古纳，加那利群岛天文研究院
Phone: +34 922 60 5258
E-mail: gil (at) iac.es
Nuno Santos, Sergio Sousa
Centro de Astrofisica da Universidade do Porto,Portugal
葡萄牙，波尔图大学，空间研究中心
Phone: +351 226 089 893
E-mail: Nuno.Santos (at) astro.up.pt, sousasag (at) astro.up.pt
Michel Mayor, Stéphane Udry
Observatory of Geneva University, Switzerland
瑞士，日内瓦天文台
Phone: +41 22 379 22 00
Email: Michel.Mayor (at) obs.unige.ch, Stephane.Udry (at) obs.unige.ch
环绕Gliese的行星系统（艺术想象图）
本帖最后由 其祥 于 2009-11-14 13:29 编辑
Burning lithium inside a star
恒星内部的锂燃烧
原始链接：http://www.eso.org/gallery/v/ESOPIA/illustrations/phot-42a-09-fullres.tif.html
Artist’s impression of a baby star still surrounded by a protoplanetary disc in which planets are forming. Using ESO’s very successful HARPS spectrograph, a team of astronomers has found that Sun-like stars which host planets have destroyed their lithium much more efficiently than planet-free stars. This finding does not only shed light on the low levels of this chemical element in the Sun, solving a long-standing mystery, but also provides astronomers with a very efficient way to pick out the stars most likely to host planets. It is not clear what causes the lithium to be destroyed. The general idea is that the planets or the presence of the protoplanetary disc disturb the interior of the star, bringing the lithium deeper down into the star than usual, into regions where the temperature is so hot that it is destroyed.
这是一张在行星形成过程初期，被行星盘围绕的婴儿恒星的艺术幻想图。通过利用欧洲南方天文台的“行星搜索器"，一个天文学家小组发现类似太阳（有行星绕转）的恒星相比“无行星”系统的恒星更快地将锂燃烧掉。这一发现不仅阐明了为何太阳中仅含有微量的锂，解决了这个长久以来的谜团，而且也为天文学家们提供了一个用来搜寻系外行星系统（类似太阳系）非常行之有效的方法。但是，目前为何锂会衰减的机制还不是很清楚。大体上的研究表明，行星或行星盘的存在会影响其主星内部物质的运动，致使恒星内部（靠近核心处）的锂含量比平常情况下少得多，因为温度在这个区域中相当高以至于锂可以被燃烧掉。
本帖最后由 其祥 于 2009-11-14 14:12 编辑
Object Information
目标信息
ID: phot-42a-09-fullres
图片编号
Science Release: 42-09
科学报告
Size: 3000x2000
图像大小
Credit: ESO/L. Calçada
版权
Available Formats
可供下载格式
Full Size Original 12604 kB TIFF
原始全景图 http://www.eso.org/gallery/d/214467-3/phot-42a-09-fullres.tif 12.3M TIFF格式
Screensize
屏幕大小
1600px228 kB JPEG
1600像素 http://www.eso.org/gallery/d/214984-2/phot-42a-09-fullres.jpg 228K JPEG格式
pdf附件中艺术想象图
建议链接ESO的图片, 又大又快 过来学习一下！ 建议链接ESO的图片, 又大又快
gohomeman1 发表于 2009-11-13 22:12 http://www.astronomy.com.cn/bbs/images/common/back.gif
G兄稍安勿躁，还没有编辑到图片，刚才有事，刚开始翻译。只是先占领了几个楼层。BTW,PDF里的图片怎么不能另存呢，我记得是可以的啊。这次科学报告的图片不多，但是所给链接论文中的图片倒是很多。 本帖最后由 gohomeman1 于 2009-11-13 23:20 编辑
有可能是被安全性限制住了，用Acrobat专业版取消其安全性限制吧。如果还不行，就把图放大到足够大，然后使用QQ等工具截图吧，我一直使用Vista自己的截图工具。
另外第2个PDF中的图片选择几张发就是了，这是ESO的系外行星搜索广告片，就如同其宣传自己ESO怎么强一样的。第一个PDF中的图请单独发几楼，无论如何要配解说的，否则大家都看不懂在说什么。 有可能是被安全性限制住了，用Acrobat专业版取消其安全性限制吧。如果还不行，就把图放大到足够大，然后使用QQ等工具截图吧，我一直使用Vista自己的截图工具。 ...
gohomeman1 发表于 2009-11-13 23:17 http://www.astronomy.com.cn/bbs/images/common/back.gif
哦，也罢，那我也用自带的截图工具吧。我用的win7，vista我很不喜欢它，速度太慢，也可能是我内存小的原因。 不错不错啊!!LZ的翻译!!!::42::::42::::42::
zheng123 发表于 2009-11-14 06:51 http://www.astronomy.com.cn/bbs/images/common/back.gif
不敢，zheng兄过奖啦。::070821_19.jpg:: 本帖最后由 其祥 于 2009-11-14 13:55 编辑
有关系外行星知识:
维基百科中文版链接：
http://zh.wikipedia.org/zh-cn/%E ... 6%E8%A1%8C%E6%98%9F
维基百科英文版链接：
http://en.wikipedia.org/wiki/Exoplanet
此贴4#可供下载第二个pdf中部分内容可参考：
（gohomeman1兄 ESO091019：新发现32颗太阳系外行星）
http://www.astronomy.com.cn/bbs/ ... d=122180&highlight= 本帖最后由 其祥 于 2009-11-15 18:31 编辑
论文中附图说明：（不用看此楼层，后有补充）
Figure 1.
表一
Lithium abundance against effective temperature in solar-analogue stars with and without detected planets.
“无行星”恒星与“类太阳”恒星锂含量对比图。（有效温度与太阳接近）
The planet hosts and “single” stars are red filled and empty circles, respectively. The redcircle with the black point at its center indicates the Sun. The minimum detectable Li abundance varies among the stars used in this study because their spectra have different signal-to-noise ratios. The straight line log N(Li)=1.5 matches the upper envelope of the lower limits corresponding to a minimum S/N = 200 in a typical solar twin. We employ this line as a cut-off for selecting Li-depleted stars in our sample. Note that the two planet host stars with the highest Li abundance also have nearly the highest effective temperatures and therefore the thinner convective zones, which help to preserve this element. Apart from these stars, log N(Li)=1.5 is the highest value found in a planet-host star. The mean statistical errors (1σ) for the log N(Li) and Teff averaged over all stars are 0.06 dex and 30K, respectively12. Errors in log N(Li) (bottom right corner) include uncertainties in Teff and equivalent width measurement.
图中：“有行星”恒星用实心红圈表示；“无行星”恒星用空心红圈表示；太阳用空心红圈中含有黑点表示。在这项研究中所分析的恒星锂丰度的最小值不同，是因为它们的光谱有不同的信噪比。图中直线log N(Li)=1.5代表信噪比最小值为200的典型的类太阳... 我们用这条直线作为样本中选择“锂耗尽”恒星的分界线。既然两颗具有最高锂丰度的“有行星”恒星的有效温度同时也几乎是最高的，因此，对流层越薄，锂元素就会被燃烧的越少。除了这些被研究的恒星以外，log N(Li)=1.5也是目前所发现“有行星”恒星的最大值。log N(Li)的平均统计误差为1σ。。。 右下角处的log N(Li)中的错误包含有效温度以及等效宽度测量的不确定性。
Figure 2.
Lithium and physical properties of planet-host solar-analogue and comparison stars.
Chromospheric activity indices RHK were taken from the literature17, 27, 28 while rotationa lvelocities of the comparison sample stars and many planet hosts were measured from CORALIE and HARPS spectra using a cross correlation function29. Typical 1σ uncertainties for log RHK and vsini (panels (a) and (b), bottom right corner) are 0.1 dex and 0.3 km sec-1, respectively17,29. Rotational velocities of several planet-hosts were taken from the literature29,30. The metallicities were measured12 with a 1σ precision of 0.05 dex (bottom
right corner in panel (c)). In the panel (c )we plot Li abundances versus effective temperature in planet-hosts (red filled circles), and stars of the open clusters M67 (blue triangles) and NGC 6253 (open squares). The data for M67 were taken from the literature15. Li abundances in NGC 6253 have been derived from VLT/Giraffe spectra using standard methods (Randich et al., in preparation). Typical 1σ error bars (panel (c), bottom right
corner) are 0.15 dex and 100 K for log N(Li) and Teff, respectively.
（其祥注：此论文小弟个人能力有限，有很多不理解的地方。图表翻译不当之处请各位指正。） 本帖最后由 其祥 于 2009-11-14 14:24 编辑
4楼 附件2 Exoplanet Media Kit 中部分说明：
（图中演示的内容为探索发现系外行星的方法之一——掩星法）
示意图一：行星环绕时，若其在视向上挡住主星，则恒星亮度会降低。
（其祥注：太阳系称凌日）
图二：掩星法发现的两颗恒星亮度变化图。图片来源：ESO 原来翻译这么耗时耗神啊，向如gohomeman1兄等众位同好致以深切的感谢。牧夫需要大家共同的建设。 感谢楼主的翻译,工作量好大哦,呵呵!!!::42::::42::::42::
zheng123 发表于 2009-11-14 17:32 http://www.astronomy.com.cn/bbs/images/common/back.gif
zheng兄，这个工作量比起很多同好来说真的是很小很小的。。。呵呵。不过读论文确实让我头痛了。