2024年08月19日:IC 5146：茧状星云-（IC 5146: The Cocoon Nebula） 2024年08月19日:IC 5146：茧状星云-（IC 5146: The Cocoon Nebula）--原图下载{mtitle title="IC 5146：茧状星云"/}Image Credit & Copyright: Luis Romero Ventura说明: 茧状星云内有个正在形成的星团。直径将近15光年、编录号为IC 5146的茧状星云，座落在北半球夏季夜空的天鹅座方向约4,000光年远之处。如同其他的恒星形成区一样，这个位在一团不可见分子云边缘的星云，其内的氢气因受到炽热年轻恒星激发而发出泛红的辉光，而部分尘埃则因为反射星光而呈蓝色。事实上，位在星云中心附近、可能只有数百万年稚龄的亮星，除了激发星云发光之外，也在孕育恒星的分子云尘埃和气体里清出一个空穴。这幅总曝光时间长达48小时的极深空彩色影像，清楚呈现了这个满是尘埃的恒星形成区内部与周围的迷人特徵结构。{lamp/}原文：{mtitle title="IC 5146: The Cocoon Nebula"/}Image Credit & Copyright: Luis Romero VenturaExplanation: Inside the Cocoon Nebula is a newly developing cluster of stars.Cataloged asIC 5146, the beautifulnebula is nearly 15 light-years wide.Soaring high innorthern summer night skies,it's located some 4,000 light years away toward the constellation of the Swan (Cygnus). Like other star forming regions, it stands outin red, glowing, hydrogen gasexcited by young, hot stars,and dust-reflected starlightat the edge of an otherwise invisiblemolecular cloud. In fact, the bright star found near the center of this nebula is likelyonly a few hundred thousand years old, powering the nebular glow as itclears out a cavity in the molecular cloud's star forming dust and gas.A 48-hour long integration resulted in thisexceptionally deep color view tracing tantalizing features within and surrounding the dustystellarnursery.

2024年01月29日:昴宿星团：有尘埃环绕的七姐妹星团-（The Pleiades: Seven Dusty Sisters） 2024年01月29日:昴宿星团：有尘埃环绕的七姐妹星团-（The Pleiades: Seven Dusty Sisters）--原图下载{mtitle title="昴宿星团：有尘埃环绕的七姐妹星团"/}Image Credit & Copyright: Craig Stocks说明: 着名的昴宿星团正在缓缓摧毁路过的部分气体与尘埃云。昴宿星团是地球天空中最明亮的疏散星团之一，几乎在北半球的任何地方，都能用肉眼看到它的身影。在过去的100,000年里，一大片气体与尘埃恰好穿过昴宿星团，造成恒星和尘埃之间的强烈反应。这团路过的云，可能是雷德克利夫波的一部分，而拉德克利夫波则是不久才发现的、连接了我们邻近银河系的数个恒星形成区之气体和尘埃结构。来自恒星光压会显着的排斥周围泛蓝反射星云里的尘埃，其中颗粒较小的尘埃，所受到的排斥力较大。短期的结果是部分的尘埃云纠结成丝状并发生分层。这张整合了将近9小时长曝光数据的主题深空影像，是在去年由美国 犹他州的犹他沙漠远距天文台所拍摄的。（Radcliffe wave 雷德克利夫波）{lamp/}原文：{mtitle title="The Pleiades: Seven Dusty Sisters"/}Image Credit & Copyright: Craig StocksExplanation: The well-known Pleiades star cluster is slowly destroying part of a passing cloud of gas and dust.The Pleiades is the brightest open cluster of stars on Earth's sky and can be seen from almost any northerly location with the unaided eye. Over the past 100,000 years, a field of gas and dustis moving by chance right through the Pleiades star cluster and is causing a strong reaction between the stars and dust.The passing cloud might be part of the Radcliffe wave, a newly discovered structure of gas and dust connecting several regions of star formation in the nearby part of our Milky Way galaxy. Pressure from the stars' light significantly repels the dust in the surrounding bluereflection nebula, with smaller dust particles being repelled more strongly. A short-term result is that parts of the dust cloud have become filamentary and stratified.The featured deep image incorporates nearly 9 hours of exposure and was captured from Utah Desert Remote Observatory in Utah, USA, last year.

2024年01月04日:天市右垣十一：速逃星-（Zeta Oph: Runaway Star） 2024年01月04日:天市右垣十一：速逃星-（Zeta Oph: Runaway Star）--原图下载{mtitle title="天市右垣十一：速逃星"/}Image Credit: NASA, JPL-Caltech,Spitzer Space Telescope说明: 在这幅令人讚叹的红外光影像里，速逃星天市右垣十一就像一艘滑过宇宙海之船舰，产生了这道弓形震波。在这张假色影像中心附近，质量大约是20倍太阳的泛蓝天市右垣十一，正以每秒24公里的速度向左飞奔。 它前方强烈的恒星风，挤压并加热富含尘埃的星际物质，造成了这道弓形震波前沿。为何这颗恒星会高速运动呢？天市右垣十一原来可能是双星系统的成员之一，质量大于它的伴星之寿命较短，当这颗伴星发生超新星爆炸、耗损质量的同时，天市右垣十一也被抛出这个系统。位于蛇夫座方向的天市右垣十一，离我们约460光年远。它的光度约莫是太阳的65,000倍，所以如果不是周围包裹着遮光的尘埃，它会是地球夜空的亮星之一。以天市右垣十一的距离来换算，这幅宽约1.5度的影像，跨幅约有12光年。在2020年1月，美国航太总署让史匹哲太空望远镜进入安全沉睡模式，终结了它16年来探索宇宙的成功任务。 (Zeta Oph, Zeta Ophiuchi 天市右垣十一、韩){lamp/}原文：{mtitle title="Zeta Oph: Runaway Star"/}Image Credit: NASA, JPL-Caltech,Spitzer Space TelescopeExplanation: Like a ship plowing through cosmic seas,runaway star Zeta Ophiuchiproduces the arcing interstellar bow wave or bow shock seen in this stunning infrared portrait.In the false-color view, bluish Zeta Oph, a star about 20 times moremassive than the Sun, lies near the center of the frame, movingtoward the left at 24 kilometers per second.Its strong stellar wind precedes it, compressing and heating the dustyinterstellar materialand shaping the curved shock front.What set this star in motion?Zeta Oph was likely once a member of abinary star system, itscompanion star was more massive and hence shorter lived.When the companionexploded as a supernovacatastrophically losing mass, Zeta Oph was flung out of the system. About 460 light-years away, Zeta Ophis 65,000 times more luminous than theSun and would be one of the brighter starsin the sky if it weren't surrounded by obscuring dust.The image spans about 1.5 degrees or 12 light-yearsat the estimated distance ofZeta Ophiuchi.In January 2020, NASA placed the Spitzer Space Telescope in safe mode, ending its 16 successful yearsofexploring the cosmos.

2024年01月01日:NGC 1232：宏伟的螺旋星系-（NGC 1232: A Grand Design Spiral Galaxy） 2024年01月01日:NGC 1232：宏伟的螺旋星系-（NGC 1232: A Grand Design Spiral Galaxy）--原图下载{mtitle title="NGC 1232：宏伟的螺旋星系"/}Image Credit: FORS,8.2-meter VLT Antu,ESO说明: 星系之所以令人着迷，除了它们具有美丽的外观之外，也因为它们具有不可见的内涵。由极大望远镜之一所拍摄的宏伟螺旋星系NGC 1232，就是一个很好的例证。上面影像里的可见物质，绝大部分是数以百万计的亮星和黝黑的尘埃，以及它们所聚成、绕着星系核心打转的螺旋臂。而蓝色亮星所组成的疏散星团则散布在旋臂上，它们之间夹杂着由緻密星际尘埃所聚成的尘埃带。此外，这个星系还有数十亿颗不显眼但可侦测的恒星及大量的星际气体，它们加总的巨大质量，主宰了星系核心区的动力学行为。不过现行的最可信的学说指出，星系还拥有更大量形态不明的不可见物质。之所有假设有这种弥漫的暗物质之存在，部分原因是要解释星系外围区可见物质的运动。{lamp/}原文：{mtitle title="NGC 1232: A Grand Design Spiral Galaxy"/}Image Credit: FORS,8.2-meter VLT Antu,ESOExplanation: Galaxies are fascinating not only forwhat is visible, but for what is invisible.Grand spiral galaxyNGC 1232,captured in detail by one of the Very Large Telescopes,is a good example. The visible is dominated by millions ofbright stars and darkdust,caught up in a gravitational swirl ofspiral arms revolving about the center.Open clusters containingbright blue stars can be seen sprinkled along these spiral arms,while dark lanesof dense interstellardustcan be seen sprinkled between them.Less visible, but detectable, are billions of dim normalstars and vast tracts ofinterstellar gas,together wielding such high mass that theydominate the dynamics of the innergalaxy. Leading theories indicate that even greater amounts of matter are invisible, in a form we don't yet know.This pervasivedark matter is postulated, in part, to explain themotionsof the visible matter in the outer regions of galaxies.

2023年10月10日:韦伯影像：藏在猎户大星云里的天体-（Hidden Orion from Webb） [2023年10月10日:韦伯影像：藏在猎户大星云里的天体-（Hidden Orion from Webb）--原图下载](https://apod.nasa.gov/apod/image/2310/OrionNircShort_Webb_2048.jpg"onMouseOver="if (document.images)document.imagename1.src='image/2310/OrionNircLong_Webb_960.jpg';"onMouseOut="if (document.images)document.imagename1.src='image/2310/OrionNircShort_Webb_960.jpg';){mtitle title="韦伯影像：藏在猎户大星云里的天体"/}Image Credit & License: NASA, ESA, CSA, JWST; Processing: M. McCaughrean & S. Pearson说明: 猎户大星云内有隐不可见的恒星。在只能感侧可见光的肉眼里，它看起来像是猎户座内的弥漫小光斑。不过，这幅来自韦伯太空望远镜的代表色影像，是由摄于红光和近红外光的数据组合而成。因此它无比清晰的证实，猎户大星云是个由年轻恒星、炽热气体和黝黑尘埃织就的忙碌区域。而轮替影像所呈现的，则是同一区域在更长波长的近红外光之代表色影像。驱动猎户大星云（M42）的主要能量源，是位在星云中心的那群亮星所属的四边形星团。而这些亮星周围的弥漫丝缕状晕光，主成分是受热的星际尘埃。在仔细检枧这些影像之后，出乎意外的找到大量木星质量级的双天体系统（JuMBOs），而这些成对的双木系统，或许能为了解恒星到底是如何形成的提供线索。此外，包括马头星云在内的整个猎户大星云複合体，于未来的数百万年里会缓缓的消散匿蹤。{lamp/}原文：{mtitle title="Hidden Orion from Webb"/}Image Credit & License: NASA, ESA, CSA, JWST; Processing: M. McCaughrean & S. PearsonExplanation: The Great Nebula in Orion has hidden stars. To the unaided eye in visible light, it appears as a smallfuzzy patch in the constellation of Orion.But this image was taken by the Webb Space Telescope in a representative-color composite of red and very near infrared light. It confirms with impressive detail that the Orion Nebula is a busy neighborhood of young stars, hot gas, and dark dust. The rollover image shows the same image in representative colors further into the near infrared.The power behind much of the Orion Nebula (M42) is the Trapezium - a cluster of bright stars near the nebula's center. The diffuse and filamentary glow surrounding the bright stars is mostly heated interstellar dust. Detailed inspection of these images shows an unexpectedly large number of Jupiter-Mass Binary Objects (JuMBOs), pairs of Jupiter-mass objects which might give a clue to how stars are forming. The whole Orion Nebula cloud complex, which includes the Horsehead Nebula, will slowly disperse over the next few million years.

2023年10月07日:仙女大星系过去和未来的恆星-（The Once and Future Stars of Andromeda） [2023年10月07日:仙女大星系过去和未来的恆星-（The Once and Future Stars of Andromeda）--原图下载](https://apod.nasa.gov/apod/image/2310/M31_HubbleSpitzerGendler_2000.jpg"onMouseOver="if (document.images)document.imagename1.src='image/2310/M31_HubbleSubaruGendler_960.jpg';"onMouseOut="if (document.images)document.imagename1.src='image/2310/M31_HubbleSpitzerGendler_960.jpg';){mtitle title="仙女大星系过去和未来的恆星"/}Image Credit: NASA, NSF, NOAJ, Hubble, Subaru,Mayall, DSS, Spitzer; Processing & Copyright: Robert Gendler & Russell Croman说明: 这幅仙女大星系的影像，不仅显示目前恒星之所在，也呈现了未来恒星即将现身的位区。如众所熟知的，庞大美丽的仙女大星系（M31），是个离我们只有2百50万光年远的螺旋星系。这幅很有趣的仙女大星系组合影像，整合了太空与地基望远镜的观测数据，以同时呈现此星系在可见光及非可见光波段的景观。影像里的白与蓝色、呈现哈伯、昴宿、及Mayall望远镜的可见光数据，用以突显M31目前恒星所在的位置。而来自美国航太总署．史匹哲太空望远镜的橙色红外光数据，则显示M31未来的恒星即将形成的区域。红外光数据所显示的，是仙女大星系广袤的螺旋臂上，受到恒星加热的庞然尘埃带。这些尘埃是此星系大量星际气体的示踪物，更是未来恒星形成的原材料。很可确定的是，这些新恒星很可能会形成于接下来的一亿年里，远在约50亿年后仙女座与我们的银河系合併之前。{lamp/}原文：{mtitle title="The Once and Future Stars of Andromeda"/}Image Credit: NASA, NSF, NOAJ, Hubble, Subaru,Mayall, DSS, Spitzer; Processing & Copyright: Robert Gendler & Russell CromanExplanation: This picture of Andromeda shows not only where stars are now, but where stars will be.The big, beautiful Andromeda Galaxy,M31, is a spiral galaxya mere 2.5 million light-yearsaway. Image data from space-based and ground-based observatories have been combined here to produce this intriguing compositeview of Andromeda at wavelengths bothinside and outside normally visible light.The visible lightshows where M31's stars are now, highlighted inwhite and blue hues and imaged by the Hubble, Subaru, and Mayall telescopes. The infrared lightshows where M31's future stars will soon form,highlighted in orange hues and imaged by NASA's Spitzer Space Telescope. The infrared light tracks enormous lanes of dust, warmed by stars, sweeping along Andromeda's spiral arms. This dust is a tracer of the galaxy's vastinterstellar gas, raw material for future star formation. Of course, the new stars will likely form over the next hundred million years or so.That's well before Andromeda merges with our Milky Way Galaxy in about 5 billion years.