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The Universe in Super Definition
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The_Evaporating_Planet.jpgWater Claimed in Evaporating Planet HD 209458b53 visitePlanet HD 209458b is evaporating. It is so close to its parent star that its heated atmosphere is simply expanding away into space. Some astronomers studying this distant planetary system now believe they have detected water vapor among the gases being liberated. This controversial claim, if true, would mark the first instance of planetary water beyond our Solar System, and indicate anew that life might be sustainable elsewhere in the universe. HD 209458b is known as a hot Jupiter type system because it involves a Jupiter-type planet in a Mercury-type orbit. Although spectroscopic observations from the Hubble Space Telescope are the basis for the water detection claim, the planetary system is too small and faint to image. Therefore, an artist's impression of the HD 209458b system is shown above. Research into the atmospheric composition of HD 209458b and other extrasolar planets is continuing.MareKromium
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The_Missing_Matter.jpgWhat is "missing" in the Universe?53 visiteIn the May 20, 2008, issue of The Astrophysical Journal, Charles Danforth and Mike Shull (University of Colorado, Boulder) report on NASA's Hubble Space Telescope and NASA's Far Ultraviolet Spectroscopic Explorer (FUSE) observations taken along sight-lines to 28 quasars. Their analysis represents the most detailed observations to date of how the intergalactic medium looks within about 4 Billion Light-Years of Earth.
The astronomers say they have definitively found about half of the missing normal matter, called "Baryons", in the space between the galaxies.
This illustration shows how the Hubble Space Telescope searches for missing Baryons, by looking at the light from quasars several Billion Light-Years away. Imprinted on that light are the spectral fingerprints of the missing ordinary matter that absorbs the light at specific frequencies (shown in the colorful spectra at right).
The missing Baryonic Matter helps trace out the structure of intergalactic space, called the "Cosmic Web".MareKromium
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TwoSuns-PIA09227.jpgTwin Suns53 visiteThis diagram illustrates that mature planetary systems like our own might be more common around twin, or binary, stars that are either really close together, or really far apart.
NASA's Spitzer Space Telescope observed that debris disks, which are signposts of mature planetary systems, are more abundant around the tightest and widest of binary stars it studied. Specifically, the infrared telescope found significantly more debris disks around binary stars that are 0 to 3 Astronomical Units (AU) apart (top panel) and 50 to 500 AU apart (bottom panel) than binary stars that are 3 to 50 AU apart (middle panel). An astronomical unit is the distance between Earth and the Sun.
In other words, if 2 stars are as far apart from each other as the Sun is from Jupiter (5 AU) or Pluto (40 AU), they would be unlikely to host a family of planetary bodies.
The Spitzer data also revealed that debris disks circle all the way around both members of a close-knit binary (top panel), but only a single member of a wide duo (bottom panel). This could explain why the intermediately spaced binary systems (middle panel) can be inhospitable to planetary disks: they are too far apart to support one big disk around both stars, and they are too close together to have enough room for a disk around just one star.
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TwoSuns-PIA09229.jpgTwin Suns, Planets and Asteroids53 visiteThis artist's image depicts a faraway Solar System like our own -- except for one big difference: planets and asteroids circle around not one, but two Suns. NASA's Spitzer Space Telescope found evidence that such Solar Systems might be common in the Universe. Spitzer did not see any planets directly, but it detected dust that is kicked up from disks like this one. The disks were spotted circling all the way around several double, or binary, stars, some of which were closer together than Earth is to our sun. In fact, Spitzer found more disks in orbit around close-knit binary stars than single stars. This could mean that planets prefer two parent stars to one, but more research is needed to figure out exactly what's going on.
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Unusual_Phenomenon~1.jpgUnusual Phenomenon in the Space of Saturn (sometime things go wrong...)145 visitenessun commentoMareKromium
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Upsilon Andromedae-PIA01937.jpgUpsilon Andromedae54 visiteThe top graph consists of infrared data from NASA's Spitzer Space Telescope. It tells astronomers that a distant planet, called Upsilon Andromedae b, always has a giant hot spot on the side that faces the star, while the other side is cold and dark. The artist's concepts above the graph illustrate how the planet might look throughout its orbit if viewed up close with infrared eyes.
Spitzer was able to determine the difference in temperature between the two sides of this planet by measuring the planet's infrared light, or heat, at five points during its 4.6-day-long trip around its star. The temperature rose and fell depending on which face, the sunlit or dark, was pointed toward Spitzer's cameras. Those temperature oscillations are traced by the wavy orange curve. They indicate that Upsilon Andromedae b has an extreme range of temperatures across its surface, about 1,400 degrees Celsius (2,550 degrees Fahrenheit). This means that hot gas moving across the bright side of the planet cools off by the time it reaches the dark side.
The bottom graph and artist's concepts represent what astronomers might have seen if the planet had bands of different temperatures girdling it, like Jupiter. Some astronomers had speculated that "hot-Jupiter" planets like Upsilon Andromedae b, which circle very closely around their stars, might resemble Jupiter in this way. If Upsilon Andromedae b had been like this, there would have been no difference between the average temperatures of the sunlit and dark sides to detect, and Spitzer's data would have appeared as a flat line.
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VB10-b-PIA12014.jpgThe VB10 Star System and the Solar System54 visiteThis artist's diagram compares our Solar System (below) to the VB 10 Star System. Astronomers successfully used the astrometry planet-hunting method for the first time to discover a gas planet, called VB 10b, around a very tiny star, VB 10. All of the bodies in this diagram are shown in circular insets at the same relative scales.
The VB 10 star is one of the smallest known — and holds the record for the smallest known to host a planet. It's a dim, red M-dwarf with only one-tenth the size, and one-twelfth the mass, of our sun. Its planet, on the other hand, is quite hefty, with six times the mass of Jupiter. Though the planet is less massive than the star, the two orbs would be about the same size.
The VB 10 Star System is essentially a shrunken version of our Solar System. Even though its planet is at a similar distance from its star as Mercury is from our Sun, it wouldn't receive as much heat and would be classified as a "cold Jupiter" similar to our own. If any rocky planets do orbit in the VB 10 System, they would be located even closer in than VB 10b, and could lie within the star's "Habitable Zone" — a region where temperatures are right for water to be liquid.
Astrometry involves measuring the wobble of a star on the sky, caused by an unseen planet yanking it back and forth. Because the VB 10b Planet is so big relative to its star, it really tugs the star around. The red circle seen at the center of the VB 10 system shows just how big this wobble is. Because our sun is more massive than VB 10, its planets do not cause it to wobble nearly as much.MareKromium
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W-5_Star_Forming_Region-PIA11726.jpgIn the Cosmic Hurricane...65 visiteThis image from NASA's Spitzer Space Telescope shows the nasty effects of living near a group of massive stars: radiation and winds from the massive stars (white spot in center) are blasting planet-making material away from stars like our sun. The planetary material can be seen as comet-like tails behind three stars near the center of the picture. The tails are pointing away from the massive stellar furnaces that are blowing them outward. The picture is the best example yet of multiple sun-like stars being stripped of their planet-making dust by massive stars.
The sun-like stars are about 2 three 3 million years old, an age when planets are thought to be growing out of surrounding disks of dust and gas. Astronomers say the dust being blown from the stars is from their outer disks. This means that any Earth-like planets forming around the sun-like stars would be safe, while outer planets like Uranus might be nothing more than dust in the wind.
This image shows a portion of the W5 star-forming region, located 6,500 light-years away in the constellation Cassiopeia. It is a composite of infrared data from Spitzer's infrared array camera and multiband imaging photometer. Light with a wavelength of 3.5 microns is blue, while light from the dust of 24 microns is orange-red.MareKromium
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W5-PIA11047.jpgW 5 - Stellar "Nursery" (natural colors)53 visiteGenerations of stars can be seen in this new infrared portrait from NASA's Spitzer Space Telescope. In this wispy star-forming region, called W5, the oldest stars can be seen as blue dots in the centers of the two hollow cavities (other blue dots are background and foreground stars not associated with the region). Younger stars line the rims of the cavities, and some can be seen as dots at the tips of the elephant-trunk-like pillars. The white knotty areas are where the youngest stars are forming.
W5 spans an area of sky equivalent to four full moons and is about 6500 Light-Years away in the constellation Cassiopeia. The Spitzer picture was taken over a period of 24 hours.
Like other massive star-forming regions, such as Orion and Carina, W5 contains large cavities that were carved out by radiation and winds from the region's most massive stars. According to the theory of triggered star-formation, the carving out of these cavities pushes gas together, causing it to ignite into successive generations of new stars.
This image contains some of the best evidence yet for the triggered star-formation theory. Scientists analyzing the photo have been able to show that the ages of the stars become progressively and systematically younger with distance from the center of the cavities.
This picture was taken with Spitzer's infrared array camera. It is a four-color composite, in which light with a wavelength of 3,6 microns is blue; 4,5-micron light is green; 5,8-micron light is orange; and 8-micron light is red.MareKromium
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W5-SST.jpgW 5 - Stellar "Nursery"54 visiteGenerations of stars can be seen in this new infrared portrait from NASA's Spitzer Space Telescope. In this wispy star-forming region, called W5, the oldest stars can be seen as blue dots in the centers of the two hollow cavities (other blue dots are background and foreground stars not associated with the region). Younger stars line the rims of the cavities, and some can be seen as pink dots at the tips of the elephant-trunk-like pillars. The white knotty areas are where the youngest stars are forming. Red shows heated dust that pervades the region's cavities, while green highlights dense clouds.
W5 spans an area of sky equivalent to four full moons and is about 6500 Light-Years away in the constellation Cassiopeia. The Spitzer picture was taken over a period of 24 hours.
Like other massive star-forming regions, such as Orion and Carina, W5 contains large cavities that were carved out by radiation and winds from the region's most massive stars. According to the theory of triggered star-formation, the carving out of these cavities pushes gas together, causing it to ignite into successive generations of new stars.
This image contains some of the best evidence yet for the triggered star-formation theory. Scientists analyzing the photo have been able to show that the ages of the stars become progressively and systematically younger with distance from the center of the cavities.
This is a three-color composite showing infrared observations from two Spitzer instruments. Blue represents 3,6-micron light and green shows light of 8 microns, both captured by Spitzer's infrared array camera. Red is 24-micron light detected by Spitzer's multiband imaging photometer.MareKromium
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Wasp_12b-PIA13691.jpgExo-Planet "Wasp 12b"127 visiteCaption NASA:"This artist's concept shows the searing-hot Gas Planet WASP-12b (the orange orb) and its Parent (or Host) Star. NASA's Spitzer Space Telescope discovered that the Planet has more Carbon than Oxygen, making it the first Carbon-rich Planet ever observed. Our Earth has relatively little amounts of Carbon - which it is made largely of Oxygen and Silicon.
Other gas planets in our Solar System, for example Jupiter, are expected to have less Carbon than Oxygen, but this is not known. Unlike WASP-12b, these Planets harbor water, the main Oxygen carrier, deep in their Atmospheres, where it is difficult to measure.
Concentrated Carbon can take the form of diamond, so Astronomers say that Carbon-rich Gas Planets could have abundant diamond in their interiors. WASP-12b is located roughly 1200 LY (Light Years) away in the constellation Auriga. It swings around its Parent Star every 1,1 days. Because the Planet is so close to its Parent Star, the Star's gravity stretches it slightly into an egg shape. The Star's gravity also pulls material off the Planet thus creating a disk around the Parent Star itself (shown here in transparent, white hues)".MareKromium
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YoungStar-PIA09266.jpgThe "O"-Star65 visite"The further on the edge, the hotter the intensity," sings Kenny Loggins in "Danger Zone," a song made famous by the movie "Top Gun." The same words ring true for young, cooler stars like our sun that live in the danger zones around scorching hot stars, called O-stars. The closer a young, maverick star happens to be to a super hot O-star, the more likely its burgeoning planets will be blasted into space.
This artist's animation illustrates how this process works. The movie begins by showing an O-star in a murky star-forming region. It then pans out to show a young, cooler star and its swirling disk of planet-forming material. Disks like this one, called protoplanetary disks, are where planets are born. Gas and dust in a disk clumps together into tiny balls that sweep through the material, growing in size to eventually become full-grown planets.
The young star happens to lie within the "danger zone" around the O-star, which means that it is too close to the hot star to keep its disk. Radiation and winds from the O-star boil and blow away the material, respectively. This process, called photoevaporation, is sped up here but takes anywhere from 100,000 to about 1,000,000 years. Without a disk, the young star will not be able to produce planets.
Our own sun and its suite of planets might have grown up on the edge of an O-star's danger zone before migrating to its current, spacious home. However, we know that our young sun didn't linger for too long in any hazardous territory, or our planets, and life, wouldn't be here today.
NASA's Spitzer Space Telescope surveyed the danger zones around five O-stars in the Rosette nebula. It was able to determine that the zones are spheres with a radius of approximately 1.6 light-years, or 10 trillion miles.
MareKromium
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