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منتدى علوم الفلك / صور مذهلة للمجرات والنجوم التقطها منظار الفضاء هاب
« في: سبتمبر 11, 2009, 05:03:13 مساءاً »
السلام عليكم ،،، هذا تفصيل أكثر باللغة الإنجليزية من ناسا
السلام عليكم ،،، هذا تفصيل أكثر
New Hubble Space Telescope Images
Butterfly Emerges from Stellar Demise in Planetary Nebula NGC 6302 NGC 6302:
This celestial object looks like a delicate butterfly. But it is far from serene.
What resemble dainty butterfly wings are actually roiling cauldrons of gas heated to more than 36,000 degrees Fahrenheit. The gas is tearing across space at more than 600,000 miles an hour -- fast enough to travel from Earth to the moon in 24 minutes!
A dying star that was once about five times the mass of the Sun is at the center of this fury. It has ejected its envelope of gases and is now unleashing a stream of ultraviolet radiation that is making the cast-off material glow. This object is an example of a planetary nebula, so-named because many of them have a round appearance resembling that of a planet when viewed through a small telescope.
The Wide Field Camera 3 (WFC3), a new camera aboard NASA’s Hubble Space Telescope, snapped this image of the planetary nebula, catalogued as NGC 6302, but more popularly called the Bug Nebula or the Butterfly Nebula. WFC3 was installed by NASA astronauts in May 2009, during the servicing mission to upgrade and repair the 19-year-old Hubble telescope.
NGC 6302 lies within our Milky Way galaxy, roughly 3,800 light-years away in the constellation Scorpius. The glowing gas is the star’s outer layers, expelled over about 2,200 years. The "butterfly" stretches for more than two light-years, which is about half the distance from the Sun to the nearest star, Alpha Centauri.
The central star itself cannot be seen, because it is hidden within a doughnut-shaped ring of dust, which appears as a dark band pinching the nebula in the center. The thick dust belt constricts the star’s outflow, creating the classic "bipolar" or hourglass shape displayed by some planetary nebulae.
The star’s surface temperature is estimated to be about 400,000 degrees Fahrenheit, making it one of the hottest known stars in our galaxy. Spectroscopic observations made with ground-based telescopes show that the gas is roughly 36,000 degrees Fahrenheit, which is unusually hot compared to a typical planetary nebulae.
The WFC3 image reveals a complex history of ejections from the star. The star first evolved into a huge red-giant star, with a diameter of about 1,000 times that of our Sun. It then lost its extended outer layers. Some of this gas was cast off from its equator at a relatively slow speed, perhaps as low as 20,000 miles an hour, creating the doughnut-shaped ring. Other gas was ejected perpendicular to the ring at higher speeds, producing the elongated "wings" of the butterfly-shaped structure. Later, as the central star heated up, a much faster stellar wind, a stream of charged particles travelling at more than 2 million miles an hour, plowed through the existing wing-shaped structure, further modifying its shape.
The image also shows numerous finger-like projections pointing back to the star, which may mark denser blobs in the outflow that have resisted the pressure from the stellar wind.
The nebula's outer edges are largely due to light emitted by nitrogen, which marks the coolest gas visible in the picture. WFC3 is equipped with a wide variety of filters that isolate light emitted by various chemical elements, allowing astronomers to infer properties of the nebular gas, such as its temperature, density, and composition.
The white-colored regions are areas where light is emitted by sulfur. These are regions where fast-moving gas overtakes and collides with slow-moving gas that left the star at an earlier time, producing shock waves in the gas (the bright white edges on the sides facing the central star). The white blob with the crisp edge at upper right is an example of one of those shock waves.
NGC 6302 was imaged on July 27, 2009 with Hubble’s Wide Field Camera 3 in ultraviolet and visible light. Filters that isolate emissions from oxygen, helium, hydrogen, nitrogen, and sulfur from the planetary nebula were used.
Credit: NASA.
Carina Nebula: Stars Bursting to Life in Chaotic Carina Nebula
These two images of a huge pillar of star birth demonstrate how observations taken in visible and in infrared light by NASA's Hubble Space Telescope reveal dramatically different and complementary views of an object.
The pictures demonstrate one example of the broad wavelength range of the new Wide Field Camera 3 (WFC3) aboard the Hubble telescope, extending from ultraviolet to visible to infrared light.
Composed of gas and dust, the pillar resides in a tempestuous stellar nursery called the Carina Nebula, located 7,500 light-years away in the southern constellation Carina. The pair of images shows that astronomers are given a much more complete view of the pillar and its contents when distinct details not seen at visible wavelengths are uncovered in near-infrared light.
The top image, taken in visible light, shows the top of the 3-light-year-long pillar, bathed in the glow of light from hot, massive stars off the top of the image. Scorching radiation and fast winds (streams of charged particles) from these stars are sculpting the pillar and causing new stars to form within it. Streamers of gas and dust can be seen flowing off the top of the structure.
Nestled inside this dense structure are fledgling stars. They cannot be seen in this image because they are hidden by a wall of gas and dust. Although the stars themselves are invisible, one of them is providing evidence of its existence. Thin puffs of material can be seen traveling to the left and to the right of a dark notch in the center of the pillar. The matter is part of a jet produced by a young star. Farther away, on the left, the jet is visible as a grouping of small, wispy clouds. A few small clouds are visible at a similar distance on the right side of the jet. Astronomers estimate that the jet is moving at speeds of up to 850,000 miles an hour. The jet's total length is more than 15 light-years.
In the image at bottom, taken in infrared light, the dense column and the surrounding greenish-colored gas all but disappear. Only a faint outline of the pillar remains. By penetrating the wall of gas and dust, the infrared vision of WFC3 reveals the infant star that is probably blasting the jet. Part of the jet nearest the star is more prominent in this view. These features can be seen because infrared light, unlike visible light, can pass through the dust.
Other infant stars inside the pillar also appear to emerge. Three examples are the bright star almost directly below the jet-producing star, a fainter one to its right, and a pair of stars at the top of the pillar. Winds and radiation from some of the stars are blowing away gas from their neighborhoods, carving out large cavities that appear as faint dark holes.
Surrounding the stellar nursery is a treasure chest full of stars, most of which cannot be seen in the visible-light image because dense gas clouds veil their light. Many of them are background stars.
Hubble's Wide Field Camera 3 observed the Carina Nebula July 24 through July 30, 2009. WFC3 was installed aboard Hubble in May 2009 during Servicing Mission 4. The composite image was made from filters that isolate emission from iron, magnesium, oxygen, hydrogen, and sulfur.
These Hubble observations of the Carina Nebula are part of the Hubble Servicing Mission 4 Early Release Observations.
Credit: NASA, ESA, and the Hubble SM4 ERO Team.
Omega Centauri: Colorful Stars Galore Inside Globular Star Cluster Omega Centauri
NASA's Hubble Space Telescope snapped this panoramic view of a colorful assortment of 100,000 stars residing in the crowded core of a giant star cluster.
The image reveals a small region inside the massive globular cluster Omega Centauri, which boasts nearly 10 million stars. Globular clusters, ancient swarms of stars united by gravity, are the homesteaders of our Milky Way galaxy. The stars in Omega Centauri are between 10 billion and 12 billion years old. The cluster lies about 16,000 light-years from Earth.
This is one of the first images taken by the new Wide Field Camera 3 (WFC3), installed aboard Hubble in May 2009, during Servicing Mission 4. The camera can snap sharp images over a broad range of wavelengths.
The photograph showcases the camera's color versatility by revealing a variety of stars in key stages of their life cycles.
The majority of the stars in the image are yellow-white, like our Sun. These are adult stars that are shining by hydrogen fusion. Toward the end of their normal lives, the stars become cooler and larger. These late-life stars are the orange dots in the image.
Even later in their life cycles, the stars continue to cool down and expand in size, becoming red giants. These bright red stars swell to many times larger than our Sun's size and begin to shed their gaseous envelopes.
After ejecting most of their mass and exhausting much of their hydrogen fuel, the stars appear brilliant blue. Only a thin layer of material covers their super-hot cores. These stars are desperately trying to extend their lives by fusing helium in their cores. At this stage, they emit much of their light at ultraviolet wavelengths.
When the helium runs out, the stars reach the end of their lives. Only their burned-out cores remain, and they are called white dwarfs (the faint blue dots in the image). White dwarfs are no longer generating energy through nuclear fusion and have gravitationally contracted to the size of Earth. They will continue to cool and grow dimmer for many billions of years until they become dark cinders.
Other stars that appear in the image are so-called "blue stragglers." They are older stars that acquire a new lease on life when they collide and merge with other stars. The encounters boost the stars' energy-production rate, making them appear bluer.
All of the stars in the image are cozy neighbors. The average distance between any two stars in the cluster's crowded core is only about a third of a light-year, roughly 13 times closer than our Sun's nearest stellar neighbor, Alpha Centauri. Although the stars are close together, WFC3's sharpness can resolve each of them as individual stars. If anyone lived in this globular cluster, they would behold a star-saturated sky that is roughly 100 times brighter than Earth's sky.
Globular clusters were thought to be assemblages of stars that share the same birth date. Evidence suggests, however, that Omega Centauri has at least two populations of stars with different ages. Some astronomers think that the cluster may be the remnant of a small galaxy that was gravitationally disrupted long ago by the Milky Way, losing stars and gas.
Omega Centauri is among the biggest and most massive of some 200 globular clusters orbiting the Milky Way. It is one of the few globular clusters that can be seen with the unaided eye. Named by Johann Bayer in 1603 as the 24th brightest object in the constellation Centaurus, it resembles a small cloud in the southern sky and might easily be mistaken for a comet.
Hubble observed Omega Centauri on July 15, 2009, in ultraviolet and visible light. These Hubble observations of Omega Centauri are part of the Hubble Servicing Mission 4 Early Release Observations.
Credit: NASA.
Stephan's
Quintet: Galactic Wreckage in Stephan's Quintet
A clash among members of a famous galaxy quintet reveals an assortment of stars across a wide color range, from young, blue stars to aging, red stars.
This portrait of Stephan’s Quintet, also known as Hickson Compact Group 92, was taken by the new Wide Field Camera 3 (WFC3) aboard NASA’s Hubble Space Telescope. Stephan’s Quintet, as the name implies, is a group of five galaxies. The name, however, is a bit of a misnomer. Studies have shown that group member NGC 7320, at upper left, is actually a foreground galaxy about seven times closer to Earth than the rest of the group.
Three of the galaxies have distorted shapes, elongated spiral arms, and long, gaseous tidal tails containing myriad star clusters, proof of their close encounters. These interactions have sparked a frenzy of star birth in the central pair of galaxies. This drama is being played out against a rich backdrop of faraway galaxies.
The image, taken in visible and infrared light, showcases WFC3’s broad wavelength range. The colors trace the ages of the stellar populations, showing that star birth occurred at different epochs, stretching over hundreds of millions of years. The camera’s infrared vision also peers through curtains of dust to see groupings of stars that cannot be seen in visible light.
NGC 7319, at top right, is a barred spiral with distinct spiral arms that follow nearly 180 degrees back to the bar. The blue specks in the spiral arm at the top of NGC 7319 and the red dots just above and to the right of the core are clusters of many thousands of stars. Most of the quintet is too far away even for Hubble to resolve individual stars.
Continuing clockwise, the next galaxy appears to have two cores, but it is actually two galaxies, NGC 7318A and NGC 7318B. Encircling the galaxies are young, bright blue star clusters and pinkish clouds of glowing hydrogen where infant stars are being born. These stars are less than 10 million years old and have not yet blown away their natal cloud. Far away from the galaxies, at right, is a patch of intergalactic space where many star clusters are forming.
NGC 7317, at bottom left, is a normal-looking elliptical galaxy that is less affected by the interactions.
Sharply contrasting with these galaxies is the dwarf galaxy NGC 7320 at upper left. Bursts of star formation are occurring in the galaxy’s disk, as seen by the blue and pink dots. In this galaxy, Hubble can resolve individual stars, evidence that NGC 7320 is closer to Earth. NGC 7320 is 40 million light-years from Earth. The other members of the quintet reside 290 million light-years away in the constellation Pegasus.
These farther members are markedly redder than the foreground galaxy, suggesting that older stars reside in their cores. The stars’ light also may be further reddened by dust stirred up in the encounters.
Spied by Edouard M. Stephan in 1877, Stephan’s Quintet is the first compact group ever discovered.
WFC3 observed the quintet in July and August 2009. The composite image was made by using filters that isolate light from the blue, green, and infrared portions of the spectrum, as well as emission from ionized hydrogen.
These Hubble observations are part of the Hubble Servicing Mission 4 Early Release Observations. NASA astronauts installed the camera during a servicing mission in May to upgrade and repair the 19-year-old Hubble telescope.
Credit: NASA, ESA, and the Hubble SM4 ERO Team.
Abell 370:
Gravitational Lensing in Galaxy Cluster Abell 370
The Hubble Space Telescope's newly repaired Advanced Camera for Surveys (ACS) has peered nearly 5 billion light-years away to resolve intricate details in the galaxy cluster Abell 370.
Abell 370 is one of the very first galaxy clusters where astronomers observed the phenomenon of gravitational lensing, where the warping of space by the cluster’s gravitational field distorts the light from galaxies lying far behind it. This is manifested as arcs and streaks in the picture, which are the stretched images of background galaxies.
Gravitational lensing proves a vital tool for astronomers when measuring the dark matter distribution in massive clusters, since the mass distribution can be reconstructed from its gravitational effects.
Ground-based telescopic observations in the mid-1980s of the most prominent arc (near the right-hand side of the picture) allowed astronomers to deduce that the arc was not a structure of some kind within the cluster, but the gravitationally-lensed image of an object two times farther away. Hubble resolves unseen new details in the arc that reveal structure in the lensed background galaxy.
Galaxy clusters are the most massive structures of the universe, located at the crossing of the filaments of the cosmic web of dark matter. The most massive clusters can contain up to 1,000 galaxies and intergalactic hot gas, all held together primarily by the gravity of dark matter.
These observations were made with Hubble's Advanced Camera for Surveys (ACS) in its Wide Field mode on July 16, 2009. The composite image was made using filters that isolate light from green, red, and infrared wavelengths.
These Hubble data are part of the Hubble Servicing Mission 4 Early Release Observations.
Credit: NASA, ESA, the Hubble SM4 ERO Team, and ST-ECF.
NGC 6217:
Barred Spiral Galaxy NGC 6217
This image of barred spiral galaxy NGC 6217 is the first image of a celestial object taken with the newly repaired Advanced Camera for Surveys (ACS) aboard the Hubble Space Telescope. The camera was restored to operation during the STS-125 servicing mission in May to upgrade Hubble.
The barred spiral galaxy NGC 6217 was photographed on June 13 and July 8, 2009, as part of the initial testing and calibration of Hubble's ACS.
The galaxy lies 6 million light-years away in the north circumpolar constellation Ursa Major.
Credit: NASA, ESA, and the Hubble SM4 ERO Team.
السلام عليكم ،،، هذا تفصيل أكثر
New Hubble Space Telescope Images
Butterfly Emerges from Stellar Demise in Planetary Nebula NGC 6302 NGC 6302:
This celestial object looks like a delicate butterfly. But it is far from serene.
What resemble dainty butterfly wings are actually roiling cauldrons of gas heated to more than 36,000 degrees Fahrenheit. The gas is tearing across space at more than 600,000 miles an hour -- fast enough to travel from Earth to the moon in 24 minutes!
A dying star that was once about five times the mass of the Sun is at the center of this fury. It has ejected its envelope of gases and is now unleashing a stream of ultraviolet radiation that is making the cast-off material glow. This object is an example of a planetary nebula, so-named because many of them have a round appearance resembling that of a planet when viewed through a small telescope.
The Wide Field Camera 3 (WFC3), a new camera aboard NASA’s Hubble Space Telescope, snapped this image of the planetary nebula, catalogued as NGC 6302, but more popularly called the Bug Nebula or the Butterfly Nebula. WFC3 was installed by NASA astronauts in May 2009, during the servicing mission to upgrade and repair the 19-year-old Hubble telescope.
NGC 6302 lies within our Milky Way galaxy, roughly 3,800 light-years away in the constellation Scorpius. The glowing gas is the star’s outer layers, expelled over about 2,200 years. The "butterfly" stretches for more than two light-years, which is about half the distance from the Sun to the nearest star, Alpha Centauri.
The central star itself cannot be seen, because it is hidden within a doughnut-shaped ring of dust, which appears as a dark band pinching the nebula in the center. The thick dust belt constricts the star’s outflow, creating the classic "bipolar" or hourglass shape displayed by some planetary nebulae.
The star’s surface temperature is estimated to be about 400,000 degrees Fahrenheit, making it one of the hottest known stars in our galaxy. Spectroscopic observations made with ground-based telescopes show that the gas is roughly 36,000 degrees Fahrenheit, which is unusually hot compared to a typical planetary nebulae.
The WFC3 image reveals a complex history of ejections from the star. The star first evolved into a huge red-giant star, with a diameter of about 1,000 times that of our Sun. It then lost its extended outer layers. Some of this gas was cast off from its equator at a relatively slow speed, perhaps as low as 20,000 miles an hour, creating the doughnut-shaped ring. Other gas was ejected perpendicular to the ring at higher speeds, producing the elongated "wings" of the butterfly-shaped structure. Later, as the central star heated up, a much faster stellar wind, a stream of charged particles travelling at more than 2 million miles an hour, plowed through the existing wing-shaped structure, further modifying its shape.
The image also shows numerous finger-like projections pointing back to the star, which may mark denser blobs in the outflow that have resisted the pressure from the stellar wind.
The nebula's outer edges are largely due to light emitted by nitrogen, which marks the coolest gas visible in the picture. WFC3 is equipped with a wide variety of filters that isolate light emitted by various chemical elements, allowing astronomers to infer properties of the nebular gas, such as its temperature, density, and composition.
The white-colored regions are areas where light is emitted by sulfur. These are regions where fast-moving gas overtakes and collides with slow-moving gas that left the star at an earlier time, producing shock waves in the gas (the bright white edges on the sides facing the central star). The white blob with the crisp edge at upper right is an example of one of those shock waves.
NGC 6302 was imaged on July 27, 2009 with Hubble’s Wide Field Camera 3 in ultraviolet and visible light. Filters that isolate emissions from oxygen, helium, hydrogen, nitrogen, and sulfur from the planetary nebula were used.
Credit: NASA.
Carina Nebula: Stars Bursting to Life in Chaotic Carina Nebula
These two images of a huge pillar of star birth demonstrate how observations taken in visible and in infrared light by NASA's Hubble Space Telescope reveal dramatically different and complementary views of an object.
The pictures demonstrate one example of the broad wavelength range of the new Wide Field Camera 3 (WFC3) aboard the Hubble telescope, extending from ultraviolet to visible to infrared light.
Composed of gas and dust, the pillar resides in a tempestuous stellar nursery called the Carina Nebula, located 7,500 light-years away in the southern constellation Carina. The pair of images shows that astronomers are given a much more complete view of the pillar and its contents when distinct details not seen at visible wavelengths are uncovered in near-infrared light.
The top image, taken in visible light, shows the top of the 3-light-year-long pillar, bathed in the glow of light from hot, massive stars off the top of the image. Scorching radiation and fast winds (streams of charged particles) from these stars are sculpting the pillar and causing new stars to form within it. Streamers of gas and dust can be seen flowing off the top of the structure.
Nestled inside this dense structure are fledgling stars. They cannot be seen in this image because they are hidden by a wall of gas and dust. Although the stars themselves are invisible, one of them is providing evidence of its existence. Thin puffs of material can be seen traveling to the left and to the right of a dark notch in the center of the pillar. The matter is part of a jet produced by a young star. Farther away, on the left, the jet is visible as a grouping of small, wispy clouds. A few small clouds are visible at a similar distance on the right side of the jet. Astronomers estimate that the jet is moving at speeds of up to 850,000 miles an hour. The jet's total length is more than 15 light-years.
In the image at bottom, taken in infrared light, the dense column and the surrounding greenish-colored gas all but disappear. Only a faint outline of the pillar remains. By penetrating the wall of gas and dust, the infrared vision of WFC3 reveals the infant star that is probably blasting the jet. Part of the jet nearest the star is more prominent in this view. These features can be seen because infrared light, unlike visible light, can pass through the dust.
Other infant stars inside the pillar also appear to emerge. Three examples are the bright star almost directly below the jet-producing star, a fainter one to its right, and a pair of stars at the top of the pillar. Winds and radiation from some of the stars are blowing away gas from their neighborhoods, carving out large cavities that appear as faint dark holes.
Surrounding the stellar nursery is a treasure chest full of stars, most of which cannot be seen in the visible-light image because dense gas clouds veil their light. Many of them are background stars.
Hubble's Wide Field Camera 3 observed the Carina Nebula July 24 through July 30, 2009. WFC3 was installed aboard Hubble in May 2009 during Servicing Mission 4. The composite image was made from filters that isolate emission from iron, magnesium, oxygen, hydrogen, and sulfur.
These Hubble observations of the Carina Nebula are part of the Hubble Servicing Mission 4 Early Release Observations.
Credit: NASA, ESA, and the Hubble SM4 ERO Team.
Omega Centauri: Colorful Stars Galore Inside Globular Star Cluster Omega Centauri
NASA's Hubble Space Telescope snapped this panoramic view of a colorful assortment of 100,000 stars residing in the crowded core of a giant star cluster.
The image reveals a small region inside the massive globular cluster Omega Centauri, which boasts nearly 10 million stars. Globular clusters, ancient swarms of stars united by gravity, are the homesteaders of our Milky Way galaxy. The stars in Omega Centauri are between 10 billion and 12 billion years old. The cluster lies about 16,000 light-years from Earth.
This is one of the first images taken by the new Wide Field Camera 3 (WFC3), installed aboard Hubble in May 2009, during Servicing Mission 4. The camera can snap sharp images over a broad range of wavelengths.
The photograph showcases the camera's color versatility by revealing a variety of stars in key stages of their life cycles.
The majority of the stars in the image are yellow-white, like our Sun. These are adult stars that are shining by hydrogen fusion. Toward the end of their normal lives, the stars become cooler and larger. These late-life stars are the orange dots in the image.
Even later in their life cycles, the stars continue to cool down and expand in size, becoming red giants. These bright red stars swell to many times larger than our Sun's size and begin to shed their gaseous envelopes.
After ejecting most of their mass and exhausting much of their hydrogen fuel, the stars appear brilliant blue. Only a thin layer of material covers their super-hot cores. These stars are desperately trying to extend their lives by fusing helium in their cores. At this stage, they emit much of their light at ultraviolet wavelengths.
When the helium runs out, the stars reach the end of their lives. Only their burned-out cores remain, and they are called white dwarfs (the faint blue dots in the image). White dwarfs are no longer generating energy through nuclear fusion and have gravitationally contracted to the size of Earth. They will continue to cool and grow dimmer for many billions of years until they become dark cinders.
Other stars that appear in the image are so-called "blue stragglers." They are older stars that acquire a new lease on life when they collide and merge with other stars. The encounters boost the stars' energy-production rate, making them appear bluer.
All of the stars in the image are cozy neighbors. The average distance between any two stars in the cluster's crowded core is only about a third of a light-year, roughly 13 times closer than our Sun's nearest stellar neighbor, Alpha Centauri. Although the stars are close together, WFC3's sharpness can resolve each of them as individual stars. If anyone lived in this globular cluster, they would behold a star-saturated sky that is roughly 100 times brighter than Earth's sky.
Globular clusters were thought to be assemblages of stars that share the same birth date. Evidence suggests, however, that Omega Centauri has at least two populations of stars with different ages. Some astronomers think that the cluster may be the remnant of a small galaxy that was gravitationally disrupted long ago by the Milky Way, losing stars and gas.
Omega Centauri is among the biggest and most massive of some 200 globular clusters orbiting the Milky Way. It is one of the few globular clusters that can be seen with the unaided eye. Named by Johann Bayer in 1603 as the 24th brightest object in the constellation Centaurus, it resembles a small cloud in the southern sky and might easily be mistaken for a comet.
Hubble observed Omega Centauri on July 15, 2009, in ultraviolet and visible light. These Hubble observations of Omega Centauri are part of the Hubble Servicing Mission 4 Early Release Observations.
Credit: NASA.
Stephan's
Quintet: Galactic Wreckage in Stephan's Quintet
A clash among members of a famous galaxy quintet reveals an assortment of stars across a wide color range, from young, blue stars to aging, red stars.
This portrait of Stephan’s Quintet, also known as Hickson Compact Group 92, was taken by the new Wide Field Camera 3 (WFC3) aboard NASA’s Hubble Space Telescope. Stephan’s Quintet, as the name implies, is a group of five galaxies. The name, however, is a bit of a misnomer. Studies have shown that group member NGC 7320, at upper left, is actually a foreground galaxy about seven times closer to Earth than the rest of the group.
Three of the galaxies have distorted shapes, elongated spiral arms, and long, gaseous tidal tails containing myriad star clusters, proof of their close encounters. These interactions have sparked a frenzy of star birth in the central pair of galaxies. This drama is being played out against a rich backdrop of faraway galaxies.
The image, taken in visible and infrared light, showcases WFC3’s broad wavelength range. The colors trace the ages of the stellar populations, showing that star birth occurred at different epochs, stretching over hundreds of millions of years. The camera’s infrared vision also peers through curtains of dust to see groupings of stars that cannot be seen in visible light.
NGC 7319, at top right, is a barred spiral with distinct spiral arms that follow nearly 180 degrees back to the bar. The blue specks in the spiral arm at the top of NGC 7319 and the red dots just above and to the right of the core are clusters of many thousands of stars. Most of the quintet is too far away even for Hubble to resolve individual stars.
Continuing clockwise, the next galaxy appears to have two cores, but it is actually two galaxies, NGC 7318A and NGC 7318B. Encircling the galaxies are young, bright blue star clusters and pinkish clouds of glowing hydrogen where infant stars are being born. These stars are less than 10 million years old and have not yet blown away their natal cloud. Far away from the galaxies, at right, is a patch of intergalactic space where many star clusters are forming.
NGC 7317, at bottom left, is a normal-looking elliptical galaxy that is less affected by the interactions.
Sharply contrasting with these galaxies is the dwarf galaxy NGC 7320 at upper left. Bursts of star formation are occurring in the galaxy’s disk, as seen by the blue and pink dots. In this galaxy, Hubble can resolve individual stars, evidence that NGC 7320 is closer to Earth. NGC 7320 is 40 million light-years from Earth. The other members of the quintet reside 290 million light-years away in the constellation Pegasus.
These farther members are markedly redder than the foreground galaxy, suggesting that older stars reside in their cores. The stars’ light also may be further reddened by dust stirred up in the encounters.
Spied by Edouard M. Stephan in 1877, Stephan’s Quintet is the first compact group ever discovered.
WFC3 observed the quintet in July and August 2009. The composite image was made by using filters that isolate light from the blue, green, and infrared portions of the spectrum, as well as emission from ionized hydrogen.
These Hubble observations are part of the Hubble Servicing Mission 4 Early Release Observations. NASA astronauts installed the camera during a servicing mission in May to upgrade and repair the 19-year-old Hubble telescope.
Credit: NASA, ESA, and the Hubble SM4 ERO Team.
Abell 370:
Gravitational Lensing in Galaxy Cluster Abell 370
The Hubble Space Telescope's newly repaired Advanced Camera for Surveys (ACS) has peered nearly 5 billion light-years away to resolve intricate details in the galaxy cluster Abell 370.
Abell 370 is one of the very first galaxy clusters where astronomers observed the phenomenon of gravitational lensing, where the warping of space by the cluster’s gravitational field distorts the light from galaxies lying far behind it. This is manifested as arcs and streaks in the picture, which are the stretched images of background galaxies.
Gravitational lensing proves a vital tool for astronomers when measuring the dark matter distribution in massive clusters, since the mass distribution can be reconstructed from its gravitational effects.
Ground-based telescopic observations in the mid-1980s of the most prominent arc (near the right-hand side of the picture) allowed astronomers to deduce that the arc was not a structure of some kind within the cluster, but the gravitationally-lensed image of an object two times farther away. Hubble resolves unseen new details in the arc that reveal structure in the lensed background galaxy.
Galaxy clusters are the most massive structures of the universe, located at the crossing of the filaments of the cosmic web of dark matter. The most massive clusters can contain up to 1,000 galaxies and intergalactic hot gas, all held together primarily by the gravity of dark matter.
These observations were made with Hubble's Advanced Camera for Surveys (ACS) in its Wide Field mode on July 16, 2009. The composite image was made using filters that isolate light from green, red, and infrared wavelengths.
These Hubble data are part of the Hubble Servicing Mission 4 Early Release Observations.
Credit: NASA, ESA, the Hubble SM4 ERO Team, and ST-ECF.
NGC 6217:Barred Spiral Galaxy NGC 6217
This image of barred spiral galaxy NGC 6217 is the first image of a celestial object taken with the newly repaired Advanced Camera for Surveys (ACS) aboard the Hubble Space Telescope. The camera was restored to operation during the STS-125 servicing mission in May to upgrade Hubble.
The barred spiral galaxy NGC 6217 was photographed on June 13 and July 8, 2009, as part of the initial testing and calibration of Hubble's ACS.
The galaxy lies 6 million light-years away in the north circumpolar constellation Ursa Major.
Credit: NASA, ESA, and the Hubble SM4 ERO Team.
