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Nebulae and Gas Clouds
Trapezium Cluster in the Orion Nebula  The brown dwarfs are too dim to be seen in a visible-light image taken by the Hubble telescope's Wide Field and Planetary Camera 2. This view also doesn't show the assemblage of infant stars seen in the near-infrared image. That's because the young stars are embedded in dense clouds of dust and gas. The Hubble telescope's near-infrared camera, the Near Infrared Camera and Multi-Object Spectrometer, penetrated those clouds to capture a view of those objects. The planetary nebula NGC 5979  Stars like the Sun spend most of their life quietly converting hydrogen into helium. However when the hydrogen in the stellar core is exhausted, they start a short phase of much more rapid evolution, growing in size and brightness, to become cooler red giants that begin to eject large amounts of gas and dust as a slow stellar wind. When the star has lost most of its mass, it heats up again and brightens so that the ejected material begins to glow. At the same time a faster wind sweeps through to clear out the cocoon of obscuring material and so a planetary nebula is born. Hubble Watches Star Tear Apart its Neighborhood  NASA's Hubble Space Telescope has snapped a view of a stellar demolition zone in our Milky Way Galaxy: a massive star, nearing the end of its life, tearing apart the shell of surrounding material it blew off 250,000 years ago with its strong stellar wind. The shell of material, dubbed the Crescent Nebula (NGC 6888), surrounds the "hefty," aging star WR 136, an extremely rare and short-lived class of super-hot star called a Wolf-Rayet. Hubble's multicolored picture reveals with unprecedented clarity that the shell of matter is a network of filaments and dense knots, all enshrouded in a thin "skin" of gas (seen in blue). The whole structure looks like oatmeal trapped inside a balloon. The skin is glowing because it is being blasted by ultraviolet light from WR 136.
Nebula N 81  NASA's Hubble Space Telescope has peered deep into a neighboring galaxy to reveal details of the formation of new stars. Hubble's target was a newborn star cluster within the Small Magellanic Cloud, a small galaxy that is a satellite of our own Milky Way. The new images show young, brilliant stars cradled within a nebula, or glowing cloud of gas, cataloged as N 81. NGC 2440  NGC 2440 is another planetary nebula ejected by a dying star, but it hasa much more chaotic structure than NGC 2346. The central star of NGC2440 is one of the hottest known, with a surface temperature near 200,000 degrees Celsius. The complex structure of the surrounding nebulasuggests to some astronomers that there have been periodic oppositelydirected outflows from the central star, somewhat similar to that in NGC2346, but in the case of NGC 2440 these outflows have been episodic, andin different directions during each episode. The nebula is also rich inclouds of dust, some of which form long, dark streaks pointing away fromthe central star. In addition to the bright nebula, which glows becauseof fluorescence due to ultraviolet radiation from the hot star, NGC 2440is surrounded by a much larger cloud of cooler gas which is invisible in ordinary light but can be detected with infrared telescopes. NGC 2440 lies about 4,000 light-years from Earth in thedirection of the constellation Puppis. NGC 2346  NGC 2346, is a so-called "planetary nebula," which is ejected from Sun-like stars which are nearthe ends of their lives. NGC 2346 is remarkable because its centralstar is known to be actually a very close pair of stars, orbiting each other every 16 days. It is believed that the binary star was originally more widely separated. However, when one component of the binary evolved, expanded in size, and became a red-giant star, it literally swallowed its companion star. The companion star then spiralled downwards inside the red giant, and in the process spewed out gas into aring around the binary system. Later on, when the hot core of the redgiant was exposed, it developed a faster stellar wind, which emerged perpendicularly to the ring and inflated two huge "bubbles." This two-stage process is believed to have resulted in the butterfly-like shape of the nebula. NGC 2346 lies about 2,000 light-years away from us, and is about one-third of a light-year in size.
Hubble's Variable Nebula (NGC 2261)  Hubble's variable nebula is named after the American astronomer Edwin P. Hubble, who carried out some of the early studies of this object. It is a fan-shaped cloud of gas and dust which is illuminated by R Monocerotis (R Mon), the bright star at the bottom end of the nebula. Dense condensations of dust near the starcast shadows out into the nebula, and as they move the illuminationc hanges, giving rise to the variations first noted by Hubble. The star itself, lying about 2,500 light-years from Earth, cannot be seen directly, but only through light scattered off of dust particles in the surrounding nebula. R Mon is believed to have a mass of about 10 times that of the Sun, and to have an age of only 300,000 years. There is probably a symmetrical counterpart of the fan-shaped nebula on the southern side of the star, but it is heavily obscured from view by dust lying between this lobe and our line of sight. A View of HH 32  HH 32 is an excellent example of a "Herbig-Haro object," which is formed when young stars eject jets of material back into interstellar space. This object, about 1,000 light-years from Earth, is somewhat older than Hubble's variable nebula, and the wind from the bright central star has already cleared much of the dust out of the central region, thus exposing the star to direct view. Many young stars, like the central object in HH 32, are surrounded by disks of gas and dust that form as additional material is attracted gravitationally from the surrounding nebula. A Grand View of the Birth of "Hefty" Stars - 30 Doradus Nebula  This visible light picture, represents a sweeping view of the 30 Doradus Nebula.
N83B - massive infant stars rock their cradle  Extremely intense radiation from newly born, ultra-bright stars has blown a glowing spherical bubble in the nebula N83B, also known as NGC 1748. A new NASA Hubble Space Telescope image has helped to decipher the complex interplay of gas and radiation of a star-forming region in a nearby galaxy. The image graphically illustrates just how these massive stars sculpt their environment by generating powerful winds that alter the shape of the parent gaseous nebula. These processes are also seen in our Milky Way in regions like the Orion Nebula. A Tantalising Veil  This ground-based image of the Cygnus Loop measures 3 x 2 degrees and was taken with the Oschin Schmidt Telescope and scanned as part of the Digitized Sky Survey. Trapezium Cluster in the Orion Nebula  Probing deep within a neighborhood stellar nursery, NASA's Hubble Space Telescope uncovered a swarm of newborn brown dwarfs. The orbiting observatory's near-infrared camera revealed about 50 of these objects throughout the Orion Nebula's Trapezium cluster about 1,500 light-years from Earth
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