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    [双语文摘] 神秘的尘埃消失事件

    The Mysterious Case of the Disappearing Dust



    This artist's concept illustrates a dusty planet-forming disk, similar to the one that vanished around the star called TYC 8241 2652. Image credit: NASA/JPL-Caltech Larger view

    示意图:这是类似消失的环绕在名为TYC8241 2652恒星周围的行星构成尘埃。作者:NASA/JPL-Caltech

    Imagine if the rings of Saturn suddenly disappeared. Astronomers have witnessed the equivalent around a young sun-like star called TYC 8241 2652. Enormous amounts of dust known to circle the star are unexpectedly nowhere to be found.

    天文学家已经目睹了在一个年轻的太阳般的恒星(TYC8241 2652)周围的(行星构成尘埃)的消失。你们可以试想一下,就像土星环突然消失了一样。已知数量巨大的尘埃如今却出人意外的消失不见无处可寻。

    "It's like the classic magician's trick: now you see it, now you don't. Only in this case we're talking about enough dust to fill an inner solar system and it really is gone!" said Carl Melis of the University of California, San Diego, who led the new study appearing in the July 5 issue of the journal Nature.


    A dusty disk around TYC 8241 2652 was first seen by the NASA Infrared Astronomical Satellite (IRAS) in 1983, and continued to glow brightly for 25 years. The dust was thought to be due to collisions between forming planets, a normal part of planet formation. Like Earth, warm dust absorbs the energy of visible starlight and reradiates that energy as infrared, or heat, radiation.

    这围绕TYC8241 2652的尘埃盘最早于1983年被NASA的红外天文卫星(IRAS)发现,并观测到它连续25年的发光。这些尘埃被认为是行星成型过程中的正常的组成部分——尘埃互相碰撞凝聚的过程。像地球一样,尘埃吸收着可见星光的能量和再辐射例如红外线,热量,辐射等。

    The first strong indication of the disk's disappearance came from images taken in January 2010 by NASA's Wide-field Infrared Survey Explorer, or WISE. An infrared image obtained at the Gemini telescope in Chile on May 1, 2012, confirmed that the dust has now been gone for two-and-a-half years.


    "Nothing like this has ever been seen in the many hundreds of stars that astronomers have studied for dust rings," said co-author Ben Zuckerman of UCLA, whose research is funded by NASA. "This disappearance is remarkably fast even on a human time scale, much less an astronomical scale. The dust disappearance at TYC 8241 2652 was so bizarre and so quick, initially I figured that our observations must simply be wrong in some strange way."

    “这样的事情在过去天文学者对数百个恒星尘埃环的研究中从未见过”合著者加州大学洛杉矶分校的本·朱克曼说(他的研究是NASA资助的),“这种消失是非常快的甚至在人类的时间尺度上,比一个天文时间单位要小的多(注:众所周知,天文中时间单位尺度都是很长的)。TYC8241 2652的尘埃盘消失的如此离奇与迅速,以至于我们最初认为可能是我们犯了一些简单的错误。”

    The astronomers have come up with a couple of possible solutions to the mystery, but they say none are compelling. One possibility is that gas produced in the impact that released the dust helped to quickly drag the dust particles into the star and thus to their doom. In another possibility, collisions of large rocks left over from an original major impact provide a fresh infusion of dust particles into the disk, which caused the dust grains to chip apart into smaller and smaller pieces.


    The result is based upon multiple sets of observations of TYC 8241 2652 obtained with the Thermal-Region Camera Spectrograph on the Gemini South telescope in Chile; IRAS; WISE; NASA's Infrared Telescope on Mauna Kea in Hawaii; the European Space Agency's Herschel Space Telescope, in which NASA plays an important role; and the Japanese/European Space Agency AKARI infrared satellite.

    结论的得出是依据智利南双子望远镜远红外摄像摄谱仪、IRAS、WISE、夏威夷冒纳基的NASA红外望远镜、欧洲航天局赫歇尔太空望远镜(NASA主导的)、日本/欧洲航天局Akari号红外卫星对TYC 8241 2652所获得的图像

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