A nebula in the constellation of Cassiopeia has flowing veils of gas and dust that have earned it the nickname the "Ghost Nebula." The nebula is being blasted by a torrent of radiation from a nearby blue-giant star called Gamma Cassiopeiae, which can be easily seen with the unaided eye at the center of the distinctive "W" asterism that forms the constellation. This Hubble Space Telescope view zooms in on the top of the nebula, Material is swept away from it, forming a fantail shape.
For more information, visit: hubblesite.org/contents/news-releases/2018/news-2018-42.html
Credit: NASA, ESA, and STScI; Acknowledgment: H. Arab (University of Strasbourg)
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Tags: IC 63 Ghost Nebula nebula Hubble Space Telescope Hubble space NASA Ghost Nebula IC 63
Astronomers may not have observed the fabled "Stairway to Heaven," but they have photographed something almost as intriguing: ladder-like structures surrounding a dying star.
This image, taken with NASA's Hubble Space Telescope, reveals startling details of one of the most unusual nebulae known in our Milky Way. Cataloged as HD 44179, this nebula is more commonly called the "Red Rectangle" because of its unique shape and color as seen with ground-based telescopes.
Hubble has revealed a wealth of new features in the Red Rectangle that cannot be seen with ground-based telescopes looking through Earth's turbulent atmosphere.
Hubble's sharp pictures show that the Red Rectangle is not really rectangular, but has an overall X-shaped structure, which astronomers interpret as arising from outflows of gas and dust from the star in the center. The outflows are ejected from the star in two opposing directions, producing a shape like two ice-cream cones touching at their tips. Also remarkable are straight features that appear like rungs on a ladder, making the Red Rectangle look similar to a spider web, a shape unlike that of any other known nebula in the sky. These rungs may have arisen in episodes of mass ejection from the star occurring every few hundred years. They could represent a series of nested, expanding structures similar in shape to wine glasses, seen exactly edge-on so that their rims appear as straight lines from our vantage point.
The star in the center of the Red Rectangle is one that began its life as a star similar to our Sun. It is now nearing the end of its lifetime and is in the process of ejecting its outer layers to produce the visible nebula. The shedding of the outer layers began about 14,000 years ago. In a few thousand years, the star will have become smaller and hotter, and will begin to release a flood of ultraviolet light into the surrounding nebula; at that time, gas in the nebula will begin to fluoresce, producing what astronomers call a planetary nebula.
At the present time, however, the star is still so cool that atoms in the surrounding gas do not glow, and the surrounding dust particles can only be seen because they are reflecting the starlight from the central star. In addition, there are molecules mixed in with the dust, which emit light in the red portion of the spectrum. Astronomers are not yet certain which types of molecules are producing the red color that is so striking in the Red Rectangle, but suspect that they are hydrocarbons that form in the cool outflow from the central star.
Another remarkable feature of the Red Rectangle, visible only with the superb resolution of the Hubble telescope, is the dark band passing across the central star. This dark band is the shadow of a dense disk of dust that surrounds the star. In fact, the star itself cannot be seen directly, due to the thickness of the dust disk. All we can see is light that streams out perpendicularly to the disk, and then scatters off of dust particles toward our direction. Astronomers found that the star in the center is actually a close pair of stars that orbit each other with a period of about 10 1/2 months. Interactions between these stars have probably caused the ejection of the thick dust disk that obscures our view of the binary. The disk has funneled subsequent outflows in the directions perpendicular to the disk, forming the bizarre bi-conical structure we see as the Red Rectangle. The reasons for the periodic ejections of more gas and dust, which are producing the "rungs" revealed in the Hubble image, remain unknown.
The Red Rectangle was first discovered during a rocket flight in the early 1970s, in which astronomers were searching for strong sources of infrared radiation. This infrared source lies about 2,300 light-years from Earth in the direction of the constellation Monoceros. Stars surrounded by clouds of dust are often strong infrared sources because the dust is heated by the starlight and radiates long-wavelength light. Studies of HD 44179 with ground-based telescopes revealed a rectangular shape in the dust surrounding the star in the center, leading to the name Red Rectangle, which was coined in 1973 by astronomers Martin Cohen and Mike Merrill.
This image was made from observations taken on March 17-18, 1999, with Hubble's Wide Field and Planetary Camera 2.
For more information please visit: hubblesite.org/image/1497/news_release/2004-11
Credit: NASA, ESA, Hans Van Winckel (Catholic University of Leuven, Belgium), and Martin Cohen (University of California, Berkeley)
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Tags: Red Rectangle HD 44179 Milky Way Planetary Nebula Hubble Space Telescope Nebula Hubble Space Telescope Astronomical Hubble Telescope Monoceros dying star infrared radiation WFPC2 NASA astronomy space
This close-up shot of the center of the Lagoon Nebula (Messier 8) clearly shows the delicate structures formed when the powerful radiation of young stars interacts with the hydrogen cloud they formed from.
This image was created from exposures taken with the Wide Field Channel of the Advanced Camera for Surveys on the Hubble Space Telescope. Light from glowing hydrogen is colored red. Light from ionized nitrogen is colored green, and light through a yellow filter is colored blue. The blue-white flare at the upper-left of the image is scattered light from a bright star just outside the field of view. The field of view is about 3.3 by 1.7 arcminutes.
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Credit: NASA, ESA
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Tags: Lagoon Nebula Messier 8 Hubble Space Telescope Nebula Hubble Space Telescope Astronomical Hubble Telescope M8 ultraviolet radiation star formation region
The star AG Carinae is surrounded by an expanding shell of gas and dust. The nebula is about five light-years wide, which
equals the distance from here to our nearest star, Alpha Centauri.
The huge structure was created from one or more giant eruptions
about 10,000 years ago, when our human ancestors were just beginning to farm. The star’s outer layers were blown into space—like a boiling teapot popping off its lid. The expelled
material amounts to roughly 10 times our Sun’s mass.
These outbursts are typical of a rare breed of star
called a luminous blue variable (LBV). These stars are among the most massive and brightest stars known and live for only a few million years.
AG Carinae resides 20,000 light-years away inside our Milky Way galaxy. The star’s expected lifetime is
between 5 million and 6 million years.
This image was taken to celebrate the Hubble Space Telescope's 31st anniversary.
Credit: NASA, ESA, STScI
For more information, visit: hubblesite.org/contents/news-releases/2021/news-2021-017
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This NASA Hubble Space Telescope image of the bipolar star-forming region, called Sharpless 2-106, resembles a soaring, celestial angel. The outstretched "wings" of the nebula record the contrasting imprint of heat and motion against the backdrop of a colder medium.
Sharpless 2-106 (Sh2-106 or S106 for short) lies nearly 2,000 light-years from us. The nebula measures several light-years in length. It appears in a relatively isolated region of the Milky Way Galaxy.
A massive, young star, IRS 4 (Infrared Source 4), is responsible for the furious activity we see in the nebula. Twin lobes of super-hot gas, glowing blue in this image, stretch outward from the central star. This hot gas creates the "wings" of this image.
A ring of dust and gas orbiting the star acts like a belt, cinching the expanding nebula into an "hourglass" shape. Hubble's sharp resolution reveals ripples and ridges in the gas as it interacts with the cooler interstellar medium.
Dusky red veins surround the blue emission from the nebula. The faint light emanating from the central star reflects off of tiny dust particles. This illuminates the environment around the star, showing darker filaments of dust winding beneath the blue lobes.
Detailed studies of the nebula have also uncovered several hundred brown dwarfs. At purely infrared wavelengths, more than 600 of these sub-stellar objects appear. These "failed" stars weigh less than a tenth of our Sun. Because of their low mass, they cannot produce sustained energy through nuclear fusion like our Sun does. They encompass the nebula in a small cluster.
The Hubble images were taken in February 2011 with the Wide Field Camera 3. Visible narrow-band filters that isolate the hydrogen gas were combined with near-infrared filters that show structure in the cooler gas and dust.
For more information please visit:
hubblesite.org/image/2932/news_release/2011-38
Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)
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Tags: Hubble Space Telescope Nebula Hubble Space Telescope Astronomical Hubble Telescope Sharpless 2-106 Sh2-106 S106 IRS 4 Milky Way Galaxy Infrared Souce 4 brown dwarfs WFC3 space astronomy NASA