礁湖星云孕育恒星

礁湖星云孕育恒星

ByNASA中文

Known as NGC 6523 or the Lagoon Nebula, Messier 8 is a giant cloud of gas and dust where stars are born. At about 4,000 light years from Earth, Messier 8 provides astronomers an excellent opportunity to study the properties of very young stars. Many infant stars give off copious amounts of high-energy light including X-rays, which are seen in the Chandra data (pink). The X-ray data have been combined with an optical image of Messier 8 from the Mt. Lemmon Sky Center in Arizona (blue and white). Image Credit: X-ray: NASA/CXC/SAO; Optical: Adam Block/Mount Lemmon SkyCenter/University of Arizona 梅西耶8号被称为NGC 6523或礁湖星云，它是一个巨大的气体和尘埃云，恒星在这里诞生。在距离地球约4000光年的地方，梅西耶8号为天文学家提供了一个研究非常年轻的恒星特性的绝佳机会。许多新生恒星释放出大量的高能光，包括X射线，可以在钱德拉的数据中看到(粉色)。X射线数据与来自亚利桑那州莱蒙山天空中心的梅西耶8号的光学图像(蓝白两色)相结合。 影像来源：X射线: NASA/CXC/SAO; 可见光：Adam Block/Mount Lemmon SkyCenter/University of Arizona

猎户座星云内部一瞥

猎户座星云内部一瞥

ByNASA中文

This dramatic image from January 2006 offers a peek inside a cavern of roiling dust and gas where thousands of stars are forming. The image, taken by the Advanced Camera for Surveys (ACS) aboard the Hubble Space Telescope, represents the sharpest view ever taken of this region until this time, called the Orion Nebula. More than 3,000 stars of various sizes appear in this image. Some of them have never been seen in visible light. These stars reside in a dramatic dust-and-gas landscape of plateaus, mountains, and valleys that are reminiscent of the Grand Canyon. The Orion Nebula is a picture book of star formation, from the massive, young stars that are shaping the nebula to the pillars of dense gas that may be the…

天蝎座的强化影像

天蝎座的强化影像

ByNASA中文

2021年06月16日 Scorpius Enhanced Image Credit & Copyright: Stefan Lenz Explanation: If Scorpius looked this good to the unaided eye, humans might remember it better. Scorpius more typically appears as a few bright stars in a well-known but rarely pointed out zodiacal constellation. To get a spectacular image like this, though, one needs a good camera, a dark sky, and some sophisticated image processing. The resulting digitally-enhanced image shows many breathtaking features. Diagonal across the image right is part of the plane of our Milky Way Galaxy. Visible there are vast clouds of bright stars and long filaments of dark and intricate dust. Rising vertically on the image left are dark dust bands known as the Dark River. Several of the bright stars on the left…

哈勃发现宇宙云的银色光芒

哈勃发现宇宙云的银色光芒

ByNASA中文

This image taken with the NASA/ESA Hubble Space Telescope showcases the emission nebula NGC 2313. Emission nebulae are bright, diffuse clouds of ionized gas that emit their own light. The bright star V565 (center of the image) highlights a silvery, fan-shaped veil of gas and dust, while the right half of this image is obscured by a dense cloud of dust. Nebulae with similar shapes were once called “cometary nebulae” because the star with an accompanying bright fan looked like a comet with a bright tail. The language that astronomers use changes as we become better acquainted with the universe, and astronomical history is littered with now-obsolete phrases to describe objects in the night sky, such as “spiral nebulae” for spiral galaxies. Text credit: European…

哈勃望远镜观测到一条耀眼的宇宙项链

哈勃望远镜观测到一条耀眼的宇宙项链

ByNASA中文

The interaction of two doomed stars has created this spectacular ring adorned with bright clumps of gas ­– a diamond necklace of cosmic proportions. Fittingly known as the “Necklace Nebula,” this planetary nebula is located 15,000 light-years away from Earth in the small, dim constellation of Sagitta (the Arrow). A pair of tightly orbiting Sun-like stars produced the Necklace Nebula, which also goes by the less glamorous name of PN G054.203.4. Roughly 10,000 years ago, one of the aging stars expanded and engulfed its smaller companion, creating something astronomers call a “common envelope.” The smaller star continued to orbit inside its larger companion, increasing the bloated giant’s rotation rate until large parts of it spun outwards into space. This escaping ring of debris formed the…

哈勃望远镜拍摄到濒临毁灭的巨星

哈勃望远镜拍摄到濒临毁灭的巨星

ByNASA中文

在庆祝NASA哈勃太空望远镜发射31周年之际，天文学家将这个著名的天文台对准了一颗明亮 的 “名人星”，这是我们银河系中看到的最亮的恒星之一，被一团炽热的气体和尘埃包围着。 这颗名为船底座AG(AG Carinae)的恒星正在引力和辐射之间展开一场拉锯战，以避免自我毁灭。 在庆祝NASA哈勃太空望远镜发射31周年之际，天文学家将这个著名的天文台对准了一颗明亮 的 “名人星”，这是我们银河系中看到的最亮的恒星之一，被一团炽热的气体和尘埃包围着。 影像来源：NASA, ESA, STScI 围绕着这颗恒星的气体和尘埃的膨胀外壳大约有5光年宽，这相当于从这里到太阳以外最近的恒星半人马座的距离。 这个巨大的结构是在大约1万年前的一次或多次大喷发中形成的。这颗恒星的外层被吹进了太空——就像一个沸腾的茶壶从壶盖上炸开一样。排出的物质大约是太阳质量的10倍。 这些爆发是一种罕见的恒星的典型生命类型，被称为亮蓝色变星，这是一颗超级明亮、迷人的恒星短暂生命中的短暂抽搐阶段，它活得快，死得早。这些恒星是已知的质量最大、最亮的恒星之一。它们的寿命只有几百万年，相比之下，我们太阳的寿命大约为100亿年。船底座AG有几百万年的历史，位于距离我们2万光年的银河系内。 明亮的蓝色变星表现出双重性格：它们似乎在平静的幸福中度过了数年，然后突然暴跳如雷。这些庞然大物是极端的恒星，与太阳等普通恒星迥然不同。事实上，据估计，船底座AG的质量比我们的太阳大70倍，发出100万个太阳一样耀眼的光芒。 “我喜欢研究这类恒星，因为我对它们的不稳定性很着迷。它们正在做一些奇怪的事情，”德国波鸿鲁尔大学的发光蓝变体专家克斯汀·韦斯（Kerstin Weis）说。 这些图像是由哈勃太空望远镜上的WFC3/UVIS仪器获得的不同曝光的组合。几个滤波器被用来对狭窄的波长范围进行采样。颜色是对每个单色（灰度）图像分配不同色调（颜色）的结果，与单个滤波器相关。 影像来源：NASA, ESA, STScI 像产生星云这样的大爆发，在发蓝色变星的一生中会发生一到两次。蓝色变星只有在面临超新星自我毁灭的危险时才会抛出物质。由于其巨大的形式和超热的温度，像海市蜃楼这样的蓝色变星正在为保持稳定性而进行一场持续的战斗。 这是一场恒星内部辐射压力向外推和重力向内压之间的扳手腕比赛。这种宇宙匹配导致了恒星的膨胀和收缩。向外的压力有时会赢得胜利，恒星膨胀到如此巨大的规模，就像火山喷发一样，它的外层被吹散。但这种爆发只发生在恒星即将分裂的时候。当恒星将这些物质抛出后，它会收缩到正常的大小，回到原来的位置，静止一段时间。 这是一场来自恒星内部的辐射压力向外推和重力向内压的掰手腕比赛。这场宇宙比赛导致了恒星的膨胀和收缩。向外的压力偶尔会赢得战斗，恒星会膨胀到如此巨大的规模，以至于它的外层被炸掉，就像火山爆发一样。但是，这种爆发只发生在恒星濒临分裂的时候。在恒星喷出物质之后，它就会收缩到正常大小，重新稳定下来，并变得静止一段时间。 像其他许多发光的蓝色变星一样，船底座AG仍然不稳定。它曾经历过较小的爆发，但其威力却不如形成现在这个星云的那次。 这个巨大的结构是在大约1万年前的一次或多次大喷发中形成的。这颗恒星的外层被吹进了太空——就像一个沸腾的茶壶从壶盖上炸开一样。排出的物质大约是太阳质量的10倍。哈勃望远镜资深项目科学家詹妮弗·怀斯曼博士带我们参观了这幅令人惊叹的新图像，介绍了望远镜目前的健康状况，并总结了过去一年中哈勃望远镜对天文学的一些贡献。 视频来源：NASA’s Goddard Space Flight Center (字幕稍后附上) 虽然船底座AG现在处于静止状态，但作为一颗超热的恒星，它仍在继续喷出灼热的辐射和强大的恒星风(带电粒子流)。这股外流继续塑造着古老的星云，当流出的气体猛烈地射向移动较慢的外星云时，就会形成复杂的结构。这股风的速度高达每小时67万英里(100万公里/小时)，大约是正在膨胀的星云的10倍。随着时间的推移，热风追上了较冷的被排出的物质，将其犁入，并将其推到离恒星更远的地方。这种“扫雪机”效应清除了恒星周围的空洞。 红色物质是灼热的氢气与氮气混合。左上角弥漫的红色物质精确地指出了风穿过物质的脆弱区域并将其扫入太空。 最显著的特征，以蓝色突出显示，是蝌蚪状的丝状结构和不平衡的气泡。这些结构是被恒星反射光照亮的尘埃团。蝌蚪状的特征，在左侧和底部最为突出，是被恒星风雕琢过的更密集的尘埃团哈勃望远镜的敏锐视野详细地揭示了这些精致的结构。 这张照片是在可见光和紫外线下拍摄的。紫外线可以让我们更清楚地看到丝状尘埃的结构，它一直向下延伸到恒星。哈勃望远镜非常适合紫外线观测，因为这个波长范围只能从太空中观察到。 大质量恒星，比如船底座AG，对天文学家来说非常重要，因为它们对周围环境有着深远的影响。哈勃望远镜历史上最大的项目——作为基本标准的年轻恒星紫外线遗产库——正在研究年轻恒星的紫外线以及它们塑造周围环境的方式。 发光的蓝色变星非常罕见：在我们所在的相邻星系群的星系中，已知的只有不到50颗。这些恒星在这个阶段中花费了数万年，在宇宙时间中只是一眨眼的时间。许多恒星预计会在巨大的超新星爆炸中结束生命，这种爆炸使宇宙中的铁以外的重元素更加丰富。 哈勃琐事 哈勃太空望远镜于1990年4月24日发射升空，对大约48000个天体进行了150多万次观测。 在它31年的寿命中，该望远镜已经环绕地球运行了超过18.1万圈，总里程超过45亿英里。 哈勃望远镜的观测产生了超过169兆兆字节的数据，这些数据可供现在和未来的研究人员使用。 使用哈勃数据的天文学家已经发表了超过1.8万篇科学论文，其中900多篇发表于2020年。 哈勃太空望远镜是NASA和ESA(欧洲航天局)之间的一个国际合作项目。NASA位于马里兰州格林贝尔特的戈达德太空飞行中心管理该望远镜。位于马里兰州巴尔的摩市的太空望远镜科学研究所(STScI)负责哈勃望远镜的科学操作。STScI是由位于华盛顿特区的天文学研究大学协会为NASA运营。 参考来源： https://www.nasa.gov/feature/goddard/2021/hubble-captures-giant-star-on-the-edge-of-destruction

哈勃望远镜重访面纱星云

哈勃望远镜重访面纱星云

ByNASA中文

This image taken by the NASA/ESA Hubble Space Telescope revisits the Veil Nebula, which was featured in a previous Hubble image release. In this image, new processing techniques have been applied, bringing out fine details of the nebula’s delicate threads and filaments of ionized gas. To create this colorful image, observations were taken by Hubble’s Wide Field Camera 3 instrument using five different filters. The new post-processing methods have further enhanced details of emissions from doubly ionized oxygen (seen here in blues), ionized hydrogen, and ionized nitrogen (seen here in reds). The Veil Nebula lies around 2,100 light-years from Earth in the constellation of Cygnus (the Swan), making it a relatively close neighbor in astronomical terms. Only a small portion of the nebula was captured…

煤袋星云

煤袋星云

ByNASA中文

This stunning image captures a small region on the edge of the inky Coalsack Nebula, or Caldwell 99. Caldwell 99 is a dark nebula — a dense cloud of interstellar dust that completely blocks out visible wavelengths of light from objects behind it. The object at the center of the image is a (much smaller) protoplanetary nebula. The protoplanetary nebula phase is a late stage in the life of a star in which it has ejected a shell of hydrogen gas and is quickly heating up. This stage only lasts for a few thousand years before the protoplanetary nebula’s central star reaches roughly 30,000 Kelvin (approximately 17,000 degrees Fahrenheit). At this point, the central star is producing enough energy to make its surrounding shell of…

哈勃望远镜发现了星际间的相互作用

哈勃望远镜发现了星际间的相互作用

ByNASA中文

The life of a planetary nebula is often chaotic, from the death of its parent star to the scattering of its contents far out into space. Captured here by the NASA/ESA Hubble Space Telescope, ESO 455-10 is one such planetary nebula, located in the constellation of Scorpius (The Scorpion). The oblate shells of ESO 455-10, previously held tightly together as layers of its central star, not only give this planetary nebula its unique appearance, but also offer information about the nebula. Seen in a field of stars, the distinct asymmetrical arc of material over the north side of the nebula is a clear sign of interactions between ESO 455-10 and the interstellar medium. The interstellar medium is the material such as diffuse gas between star…

明亮的蓝色恒星

明亮的蓝色恒星

ByNASA中文

Inside star cluster NGC 602, a star-forming region in the Small Magellanic Cloud, bright, blue, newly formed stars are blowing a cavity in this nebula,sculpting the inner edge of its outer portions, slowly eroding it away and eating into the material beyond. The diffuse outer reaches of the nebula prevent the energetic outflows from streaming away from the cluster. Elephant trunk–like dust pillars point toward the hot blue stars and are telltale signs of their eroding effect. Star formation started at the center of the cluster and propagated outward, with the youngest stars still forming today along the dust ridges. Image Credit: NASA 在星团NGC 602内部，小麦哲伦星云中的恒星形成区域，明亮、蓝色、新形成的恒星正在星云中吹出一个空腔，雕刻着其外部部分的内缘，慢慢地将其腐蚀掉，并侵蚀着外面的物质。星云扩散的外层区域阻止了从星团中流出的能量。象鼻状的尘埃柱指向炽热的蓝色恒星，这是它们受到侵蚀的迹象。恒星的形成始于星团的中心，并向外传播，最年轻的恒星至今仍在沿着星尘脊形成。 影像来源：NASA