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Stars No. Hubble images remarkable double cluster
Located in the Large Magellanic Cloud, one of our neighbouring dwarf galaxies, this young globular-like star cluster is surrounded by a pattern of filamentary nebulosity that is thought to have been created during supernova blasts. It consists of a main globular cluster in the centre and a younger, smaller cluster, seen below and to the right, composed of extremely hot, blue stars and fainter, red T-Tauri stars. This wide variety of stars allows a thorough study of star formation processes.
Stars No. Globular cluster 47 Tucanae
This NASA/ESA Hubble Space Telescope image shows a globular cluster known as NGC 104 — or, more commonly, 47 Tucanae, since it is part of the constellation of Tucana (The Toucan) in the southern sky. After Omega Centauri it is the brightest globular cluster in the night sky, hosting tens of thousands of stars. Scientists using Hubble observed the white dwarfs in the cluster. These dying stars migrate from the crowded centre of the cluster to its outskirts. Whilst astronomers knew about this process they had never seen it in action, until the detailed study of 47 Tucanae.
Stars No. The oldest cluster in its cloud
This image shows NGC 121, a globular cluster in the constellation of Tucana (The Toucan). Globular clusters are big balls of old stars that orbit the centres of their galaxies like satellites — the Milky Way, for example, has around 150. NGC 121 belongs to one of our neighbouring galaxies, the Small Magellanic Cloud (SMC). It was discovered in 1835 by English astronomer John Herschel, and in recent years it has been studied in detail by astronomers wishing to learn more about how stars form and evolve. Stars do not live forever — they develop differently depending on their original mass. In many clusters, all the stars seem to have formed at the same time, although in others we see distinct populations of stars that are different ages. By studying old stellar populations in globular clusters, astronomers can effectively use them as tracers for the stellar population of their host galaxies. With an object like NGC 121, which lies close to the Milky Way, Hubble is able to resolve individual stars and get a very detailed insight. NGC 121 is around 10 billion years old, making it the oldest cluster in its galaxy; all of the SMC's other globular clusters are 8 billion years old or younger. However, NGC 121 is still several billions of years younger than its counterparts in the Milky Way and in other nearby galaxies like the Large Magellanic Cloud. The reason for this age gap is not completely clear, but it could indicate that cluster formation was initially delayed for some reason in the SMC, or that NGC 121 is the sole survivor of an older group of star clusters. This image was taken using Hubble’s Advanced Camera for Surveys (ACS). A version of this image was submitted to the Hubble’s Hidden Treasures image processing competition by contestant Stefano Campani.
Stars No. Best image of bright quasar 3C 273
This image from Hubble’s Wide Field and Planetary Camera 2 (WFPC2) is likely the best of ancient and brilliant quasar 3C 273, which resides in a giant elliptical galaxy in the constellation of Virgo (The Virgin). Its light has taken some 2.5 billion years to reach us. Despite this great distance, it is still one of the closest quasars to our home. It was the first quasar ever to be identified, and was discovered in the early 1960s by astronomer Allan Sandage. The term quasar is an abbreviation of the phrase “quasi-stellar radio source”, as they appear to be star-like on the sky. In fact, quasars are the intensely powerful centres of distant, active galaxies, powered by a huge disc of particles surrounding a supermassive black hole. As material from this disc falls inwards, some quasars — including 3C 273 — have been observed to fire off super-fast jets into the surrounding space. In this picture, one of these jets appears as a cloudy streak, measuring some 200 000 light-years in length. Quasars are capable of emitting hundreds or even thousands of times the entire energy output of our galaxy, making them some of the most luminous and energetic objects in the entire Universe. Of these very bright objects, 3C 273 is the brightest in our skies. If it was located 30 light-years from our own planet — roughly seven times the distance between Earth and Proxima Centauri, the nearest star to us after the Sun — it would still appear as bright as the Sun in the sky. WFPC2 was installed on Hubble during shuttle mission STS-61. It is the size of a small piano and was capable of seeing images in the visible, near-ultraviolet, and near-infrared parts of the spectrum.
Stars No. The Hubble eXtreme Deep Field
This image, called the Hubble eXtreme Deep Field (XDF), combines Hubble observations taken over the past decade of a small patch of sky in the constellation of Fornax. With a total of over two million seconds of exposure time, it is the deepest image of the Universe ever made, combining data from previous images including the Hubble Ultra Deep Field (taken in 2002 and 2003) and Hubble Ultra Deep Field Infrared (2009). The image covers an area less than a tenth of the width of the full Moon, making it just a 30 millionth of the whole sky. Yet even in this tiny fraction of the sky, the long exposure reveals about 5500 galaxies, some of them so distant that we see them when the Universe was less than 5% of its current age. The Hubble eXtreme Deep Field image contains several of the most distant objects ever identified.
This stunning image of NGC 1275 was taken using the NASA/ESA Hubble Space Telescope's Advanced Camera for Surveys in July and August 2006. It provides amazing detail and resolution of the fragile filamentary structures, which show up as a reddish lacy structure surrounding the central bright galaxy NGC 1275. These filaments are cool despite being surrounded by gas that is around 55 million degrees Celsius hot. They are suspended in a magnetic field which maintains their structure and demonstrates how energy from the central black hole is transferred to the surrounding gas. By observing the filamentary structure, astronomers were, for the first time, able to estimate the magnetic field's strength. Using this information they demonstrated how the extragalactic magnetic fields have maintained the structure of the filaments against collapse caused by either gravitational forces or the violence of the surrounding cluster during their 100-million-year lifetime. This is the first time astronomers have been able to differentiate the individual threads making up such filaments to this degree. Astonishingly, they distinguished threads a mere 200 light-years across. By contrast, the filaments seen here can be a gaping 200 000 light-years long. The entire image is approximately 260 000 light-years across. Also seen in the image are impressive lanes of dust from a separate spiral galaxy. It lies partly in front of the giant elliptical central cluster galaxy and has been completed disrupted by the tidal gravitational forces within the galaxy cluster. Several striking filaments of blue newborn stars are seen crossing the image.
The picture shows Abell 2218, a rich galaxy cluster composed of thousands of individual galaxies. It sits about 2.1 billion light-years from the Earth (redshift 0.17) in the northern constellation of Draco. When used by astronomers as a powerful gravitational lens to magnify distant galaxies, the cluster allows them to peer far into the Universe. However, it not only magnifies the images of hidden galaxies, but also distorts them into long, thin arcs. Several arcs in the image can be studied in detail thanks to Hubble's sharp vision. Multiple distorted images of the same galaxies can be identified by comparing the shape of the galaxies and their colour. In addition to the giant arcs, many smaller arclets have been identified.
Thackeray's Globules in IC 2944
Strangely glowing dark clouds float serenely in this remarkable and beautiful image taken with the Hubble Space Telescope. These dense, opaque dust clouds - known as 'globules' - are silhouetted against nearby bright stars in the busy star-forming region, IC 2944. Astronomer A.D. Thackeray first spied the globules in IC 2944 in 1950. Globules like these have been known since Dutch-American astronomer Bart Bok first drew attention to such objects in 1947. But astronomers still know very little about their origin and nature, except that they are generally associated with areas of star formation, called 'HII regions' due to the presence of hydrogen gas. IC 2944 is filled with gas and dust that is illuminated and heated by a loose cluster of massive stars. These stars are much hotter and much more massive than our Sun.
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Thackeray's Globules in IC 2944
Strangely glowing dark clouds float serenely in this remarkable and beautiful image taken with the Hubble Space Telescope. These dense, opaque dust clouds - known as 'globules' - are silhouetted against nearby bright stars in the busy star-forming region, IC 2944. Astronomer A.D. Thackeray first spied the globules in IC 2944 in 1950. Globules like these have been known since Dutch-American astronomer Bart Bok first drew attention to such objects in 1947. But astronomers still know very little about their origin and nature, except that they are generally associated with areas of star formation, called 'HII regions' due to the presence of hydrogen gas. IC 2944 is filled with gas and dust that is illuminated and heated by a loose cluster of massive stars. These stars are much hotter and much more massive than our Sun.
Stars No. Hubble image of ESO 381-12
The ghostly shells of galaxy ESO 381-12 are captured here in a new image from the NASA/ESA Hubble Space Telescope, set against a backdrop of distant galaxies. The strikingly uneven structure and the clusters of stars that orbit around the galaxy suggest that ESO 381-12 may have been part of a dramatic collision sometime in its relatively recent past.
This spectacular image was captured by the NASA/ESA Hubble Space Telescope's Advanced Camera for Surveys (ACS). The bright streak slicing across the frame is an edge-on view of galaxy NGC 4762, and a number of other distant galaxies can be seen scattered in the background. NGC 4762 lies about 58 million light-years away in the constellation of Virgo (The Virgin). It is part of the Virgo Cluster, hence its alternative designation of VCC 2095 for Virgo Cluster Catalogue entry. This catalogue is a listing of just over 2000 galaxies in the area of the Virgo Cluster. The Virgo Cluster is actually prominently situated, and lies at the centre of the larger Virgo supercluster, of which our galaxy group, the Local Group, is a member. Previously thought to be a barred spiral galaxy, NGC 4762 has since been found to be a lenticular galaxy, a kind of intermediate step between an elliptical and a spiral. The edge-on view that we have of this particular galaxy makes it difficult to determine its true shape, but astronomers have found the galaxy to consist of four main components — a central bulge, a bar, a thick disc and an outer ring. The galaxy's disc is asymmetric and warped, which could potentially be explained by NGC 4762 violently cannibalising a smaller galaxy in the past. The remains of this former companion may then have settled within NGC 4762's disc, redistributing the gas and stars and so changing the disc's morphology. NGC 4762 also contains a Liner-type Active Galactic Nucleus, a highly energetic central region. This nucleus is detectable due to its particular spectral line emission, which acts as a type of "atomic fingerprint", allowing astronomers to measure the composition of the region.
Hubble's Last Look at Comet ISON Before Perihelion
As of mid-November, ISON is officially upon us. Hubble has taken its closest look yet at the innermost region of the comet, where geysers of sublimating ice are fueling a spectacular tail. Made from observations on 2 November 2013, the image combines pictures of ISON taken through blue and red filters. The round coma around ISON's nucleus is blue and the tail has a redder hue. Ice and gas in the coma reflect blue light from the Sun, while dust grains in the tail reflect more red light than blue light. This is the most colour separation seen so far in ISON and the comet, nearer than ever to the Sun, is brighter and more structured than ever before. Comet ISON will come closest to the Sun on November 28, a point in its orbit known as perihelion. Comet ISON was fairly quiet until 1 November 2013, when it experienced an outburst that doubled the amount of gas the comet emitted. After this image was taken, a second outburst shook the comet, increasing its activity by a factor of ten. Over the past couple of nights, the comet has stabilised at its new level of activity. It is now bright enough to be seen with a good pair of binoculars from a dark site, in the morning skies towards the East. Hubble Heritage release ISONblog, an online source offering analysis of Comet ISON by Hubble Space Telescope astronomers and staff at the Space Telescope Science Institute in Baltimore, USA.
This striking cosmic whirl is the centre of galaxy NGC 524, as seen with the NASA/ESA Hubble Space Telescope. This galaxy is located in the constellation of Pisces, some 90 million light-years from Earth. NGC 524 is a lenticular galaxy. Lenticular galaxies are believed to be an intermediate state in galactic evolution — they are neither elliptical nor spiral. Spirals are middle-aged galaxies with vast, pinwheeling arms that contain millions of stars. Along with these stars are large clouds of gas and dust that, when dense enough, are the nurseries where new stars are born. When all the gas is either depleted or lost into space, the arms gradually fade away and the spiral shape begins to weaken. At the end of this process, what remains is a lenticular galaxy — a bright disc full of old, red stars surrounded by what little gas and dust the galaxy has managed to cling on to. This image shows the shape of NGC 524 in detail, formed by the remaining gas surrounding the galaxy’s central bulge. Observations of this galaxy have revealed that it maintains some spiral-like motion, explaining its intricate structure. A version of this image was entered into the Hubble’s Hidden Treasures image processing competition by contestant Judy Schmidt.
Stars No. An extraordinary celestial spiral
This remarkable picture from the Advanced Camera for Surveys on the NASA/ESA Hubble Space Telescope shows one of the most perfect geometrical forms created in space. It captures the formation of an unusual pre-planetary nebula, known as IRAS 23166+1655, around the star LL Pegasi (also known as AFGL 3068) in the constellation of Pegasus (the Winged Horse). The striking picture shows what appears to be a thin spiral pattern of astonishingly regularity winding around the star, which is itself hidden behind thick dust. The spiral pattern suggests a regular periodic origin for the nebula’s shape. The material forming the spiral is moving outwards a speed of about 50 000 km/hour and, by combining this speed with the distance between layers, astronomers calculate that the shells are each separated by about 800 years.The spiral is thought to arise because LL Pegasi is a binary system, with the star that is losing material and a companion star orbiting each other. The spacing between layers in the spiral is expected to directly reflect the orbital period of the binary, which is indeed estimated to be also about 800 years.The creation and shaping of planetary nebulae is an exciting area of stellar evolution. Stars with masses from about half that of the Sun up to about eight times that of the Sun do not explode as supernovae at the ends of their lives. Instead a more regal end awaits them as their outer layers of gas are shed and drift into space, creating striking and intricate structures that to Earth-bound observers often look like dramatic watercolour paintings. IRAS 23166+1655 is just starting this process and the central star has yet to emerge from the cocoon of enveloping dust.This picture was created from images from the Wide Field Channel of the Advanced Camera for Surveys on Hubble. Images through a yellow filter (F606W, coloured blue) were combined with images through a near-infra red filter (F804W, coloured red). The exposure times were 11 minutes and 22 minutes respectively and the field of view spans about 80 arcseconds.Links Paper discussing the intriguing AFGL 3068 (PDF format)
Located in the northern celestial hemisphere, Abell 1703 is composed of over one hundred different galaxies that act as a powerful cosmic telescope, or gravitational lens. The gravitational lens produced by the massive galaxy cluster in the foreground (the yellow mostly elliptical galaxies scattered across the image) bends the light rays in a way that can stretch the images and so amplify the brightness of the light rays from more distant galaxies. In the process it distorts their shapes and produces multiple banana-shaped images of the original galaxies. The result is the stunning image seen here - a view deeper into the Universe than possible with current technology alone. Abell 1703 is located at 3 billion light-years from the Earth (redshift 0.26).
Stars No. Hubble sees galaxies galore
Galaxies, galaxies everywhere - as far as the NASA/ESA Hubble Space Telescope can see. This view of nearly 10,000 galaxies is the deepest visible-light image of the cosmos. Called the Hubble Ultra Deep Field, this galaxy-studded view represents a "deep" core sample of the universe, cutting across billions of light-years. The snapshot includes galaxies of various ages, sizes, shapes, and colours. The smallest, reddest galaxies, about 100, may be among the most distant known, existing when the universe was just 800 million years old. The nearest galaxies - the larger, brighter, well-defined spirals and ellipticals - thrived about 1 billion years ago, when the cosmos was 13 billion years old. In vibrant contrast to the rich harvest of classic spiral and elliptical galaxies, there is a zoo of oddball galaxies littering the field. Some look like toothpicks; others like links on a bracelet. A few appear to be interacting. These oddball galaxies chronicle a period when the universe was younger and more chaotic. Order and structure were just beginning to emerge. The Ultra Deep Field observations, taken by the Advanced Camera for Surveys, represent a narrow, deep view of the cosmos. Peering into the Ultra Deep Field is like looking through a 2.5 metre-long soda straw. In ground-based photographs, the patch of sky in which the galaxies reside (just one-tenth the diameter of the full Moon) is largely empty. Located in the constellation Fornax, the region is so empty that only a handful of stars within the Milky Way galaxy can be seen in the image. In this image, blue and green correspond to colours that can be seen by the human eye, such as hot, young, blue stars and the glow of Sun-like stars in the disks of galaxies. Red represents near-infrared light, which is invisible to the human eye, such as the red glow of dust-enshrouded galaxies. The image required 800 exposures taken over the course of 400 Hubble orbits around Earth. The total amount of exposure time was 11.3 days, taken between Sept. 24, 2003 and Jan. 16, 2004.
Stars No. Hubble images remarkable double cluster
Located in the Large Magellanic Cloud, one of our neighbouring dwarf galaxies, this young globular-like star cluster is surrounded by a pattern of filamentary nebulosity that is thought to have been created during supernova blasts. It consists of a main globular cluster in the centre and a younger, smaller cluster, seen below and to the right, composed of extremely hot, blue stars and fainter, red T-Tauri stars. This wide variety of stars allows a thorough study of star formation processes.