The Milky Way as seen near the Very Large Telescope in the Atacama Desert. Credit: ESO/Y. Beletsky
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The Chilean Atacama Desert boasts some of the darkest skies on Earth – which is why it is home to several telescopes, including the Very Large Telescope. This beautiful panoramic image was taken there, showing the VLT’s Unit Telescope 1, and across on the other side of the image are the Large and Small Magellanic Clouds glowing brightly. Like an arch in between is plane of our Milky Way galaxy. This awe-inspiring image was taken by ESO Photo Ambassador Yuri Beletsky. These photographers specialize in taking images of not only the night sky, but also the large telescopes that give us eyes to see across the great distances of our Universe.
A visible light image from ESO of the reflection nebula Messier 78. Credit: ESO and Igor Chekalin
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Here’s another “Hidden Treasure” from the European Southern Observatory, from the astrophotography competition where amateurs create images from unused ESO data. In this new image of Messier 78, brilliant starlight ricochets off dust particles in the nebula, illuminating it with scattered blue light and creating what is called a reflection nebula. Almost like fog around a street light, a reflection nebula shines only with the light from an embedded source that illuminates the dust. This image was taken with the Wide Field Imager on the MPG/ESO 2.2-metre telescope at the La Silla Observatory in Chile. Comparing this image with others previously taken of Messier 78 shows that remarkably, this object has changed significantly in the last ten years.
Messier 78 can easily be observed with a small telescope, being one of the brightest reflection nebulae in the sky. It lies about 1350 light-years away in the constellation of Orion (The Hunter) and can be found northeast of the easternmost star of Orion’s belt.
For those of you who want to take a look on your own:
Right Ascension: 05:46.7
Declination: +00:03
Distance: 1.6 (kly)
Visual Brightness: Magnitude 8.3
This image contains many other striking features apart from the glowing nebula. A thick band of obscuring dust stretches across the image from the upper left to the lower right, blocking the light from background stars. In the bottom right corner, many curious pink structures are also visible, which are created by jets of material being ejected from stars that have recently formed and are still buried deep in dust clouds.
Two bright stars, HD 38563A and HD 38563B, are the main powerhouses behind Messier 78. However, the nebula is home to many more stars, including a collection of about 45 low mass, young stars (less than 10 million years old) in which the cores are still too cool for hydrogen fusion to start, known as T Tauri stars. Studying T Tauri stars is important for understanding the early stages of star formation and how planetary systems are created.
Messier 78 region taken in 2006 (below) with the 4-metre Mayall telescope at Kitt Peak, Arizona with a new image from ESO.Credit: ESO/T. A. Rector/University of Alaska Anchorage, H. Schweiker/WIYN and NOAO/AURA/NSF and Igor Chekalin
But this object has changed significantly in the last ten years. In February 2004 the experienced amateur observer Jay McNeil took an image of this region with a 75 mm telescope and was surprised to see a bright nebula — the prominent fan shaped feature near the bottom of this picture — where nothing was seen on most earlier images. This object is now known as McNeil’s Nebula and it appears to be a highly variable reflection nebula around a young star.
This color picture was created from many monochrome exposures taken through blue, yellow/green and red filters, supplemented by exposures through an H-alpha filter that shows light from glowing hydrogen gas. The total exposure times were 9, 9, 17.5 and 15.5 minutes per filter, respectively.
Can galaxy NGC 157 leap tall buildings in a single bound, stop a speeding bullet or bend steel in it’s bare hands? This relatively mild-mannered galaxy has a central sweep of stars that resembles a giant “S”, almost just like the comic book hero Superman’s symbol. The image was taken by the HAWK-I (High-Acuity Wide-field K-band Imager) on the Very Large Telescope in Chile. HAWK-I looks in infrared light, allowing us to peer through the gas and dust that normally obscures our view and see parts of NCG 157 that otherwise is hidden from our optical view.
Looking at this and other galaxies like it, astronomers can learn about star formation, as the same processes that are coalescing material and creating stars in NGC 157 also took place around 4.5 billion years ago in the Milky Way to form our own star, the Sun.
NGC 157 is faint — about magnitude 11, but can be seen bigger amateur telescopes. It is located within the constellation of Cetus (the Sea Monster).
For those interested in observing this object, see this post on WikiSky.
And just in case you don’t get the Superman references:
This new image of the Orion Nebula was captured using the Wide Field Imager camera on the MPG/ESO 2.2-metre telescope at the La Silla Observatory, Chile. Credit: ESO and Igor Chekalin
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This dreamy look inside the Orion Nebula is the latest “Hidden Treasure” released by the European South Observatory, part of its contest for amateurs to sift through the mountain of data ESO has generated with their telescopes and create new images from old data. The data used for this image were selected by Igor Chekalin from Russia, and this was the seventh highest ranked entry in the competition; another of Igor’s images was the eventual overall winner.
The image is a composite of several exposures taken through a total of five different filters with the Wide Field Imager on the MPG/ESO 2.2-meter telescope at the La Silla Observatory, Chile.
The Orion Nebula, also known as Messier 42, is a huge complex of gas and dust where massive stars are forming and is the closest such region to the Earth. The glowing gas is so bright that it can be seen with the unaided eye and is a fascinating sight through a telescope. Despite its familiarity and closeness there is still much to learn about this stellar nursery. It was only in 2007, for instance, that the nebula was shown to be closer to us than previously thought: 1,350 light-years, rather than about 1,500 light-years.
The data was originally used to find that the faint red dwarfs in the star cluster associated with the glowing gas radiate much more light than had previously been thought. But the data had not been made into a color image, until now.
A new infrared view of the star formation region Messier 8, often called the Lagoon Nebula, captured by the VISTA telescope at ESO’s Paranal Observatory in Chile. Credit: ESO/VVV
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This rich and stunning new infrared view of the Lagoon Nebula shows detail never seen before. Doesn’t it make you want to dive in for a closer look? Well, you can do just in that in a video below that zooms in on all the detail. The image was captured as part of a five-year study of the Milky Way using ESO’s VISTA telescope at the Paranal Observatory in Chile. This is a small piece of a much larger image of the region surrounding the nebula, which is, in turn, only one part of a huge survey.
The survey is called VISTA Variables in the Via Lactea (VVV), and with ESO’s Visible and Infrared Survey Telescope for Astronomy (VISTA), astronomers can scour the Milky Way’s central regions for variable objects and map its structure in greater detail than ever before.
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This image of the Lagoon Nebula (also known as Messier 8,) is part of that survey. The region which lies about 4000–5000 light-years away in the constellation of Sagittarius (the Archer).
Infrared observations allow astronomers to peer behind the veil of dust that prevents them from seeing celestial objects in visible light.
Stars typically form in large molecular clouds of gas and dust, which collapse under their own weight. The Lagoon Nebula, however, is also home to a number of much more compact regions of collapsing gas and dust, called Bok globules. These dark clouds are so dense that, even in the infrared, they can block the starlight from background stars. But the most famous dark feature in the nebula, for which it is named, is the lagoon-shaped dust lane that winds its way through the glowing cloud of gas.
Hot, young stars, which give off intense ultraviolet light, are responsible for making the nebula glow brightly. But the Lagoon Nebula is also home to much younger stellar infants. Newborn stars have been detected in the nebula that are so young that they are still surrounded by their natal accretion discs. Such new born stars occasionally eject jets of matter from their poles. When this ejected material ploughs into the surrounding gas short-lived bright streaks called Herbig–Haro objects are formed, making the new-borns easy to spot. In the last five years, several Herbig–Haro objects have been detected in the Lagoon Nebula, so the baby boom is clearly still in progress here.
The globular cluster Messier 107, also known as NGC 6171. Credit: ESO
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Globular clusters form during the earliest stages in a galaxy’s development, so clusters like this one, M 107, or NGC 6171 are some of the oldest objects in the Universe. Typically, globular clusters formed about 10 billion years ago, and astronomers say that studying these objects can provide significant insights into how galaxies, and their component stars evolve. While M 107 has been observed many times, this new look from ESO shows a stunning view of this swarm of stars.
Located about 21,000 light years away, M107 is not visible to the naked eye. But, with an apparent magnitude of about eight, it can easily be observed from a dark site with binoculars or a small telescope.
The globular cluster is about 13 arcminutes across and is found in the constellation of Ophiuchus, north of the pincers of Scorpius. Roughly half of the Milky Way’s known globular clusters are actually found in the constellations of Sagittarius, Scorpius and Ophiuchus, in the general direction of the centre of the Milky Way. This is because they are all in elongated orbits around the central region and are on average most likely to be seen in this direction.
This image is composed from exposures taken through the blue, green and near-infrared filters by the Wide Field Camera (WFI) on the MPG/ESO 2.2-metre telescope at the La Silla Observatory in Chile.
NGC 520 — also known as Arp 157 -- is actually a mashup of two gigantic galaxies. Credit: ESO
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Is this galaxy exploding? Although that’s what it might look like, this is actually two gigantic galaxies crashing into each other. NGC 520 — also known as Arp 157 — is a mashup of two huge galaxies, now combining into one. We can’t really watch the process, as it happens extremely slowly — over millions of years, and the whole process started about 300 million years ago. Apr 157 is about 100,000 light-years across and is now in the middle stage of the merging process, as the two nuclei haven’t come together yet, but the two discs have. The merger features a tail of stars and a prominent dust lane. NGC 520 is one of the brightest interacting galaxies in the sky and lies in the direction of Pisces (the Fish), approximately 100 million light-years from Earth.
This image was taken by the ESO Faint Object Spectrograph and Camera attached to the 3.6-metre telescope at La Silla in Chile.
You’d need about a 4-inch telescope to see this 12th magnitude object yourself. Here’s the location: RA: 1h 24m 35.1s, Declination: +03° 47? 33?. Or put in those coordinates in Google Sky to see it there.
Artist's impression of a yellowish star being orbited by an extra-solar planet. Credit: ESO/L. Calçada
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While astronomers have detected over 500 extrasolar planets during the past 15 years, this latest one might have the most storied and unusual past. But its future is also of great interest, as it could mirror the way our own solar system might meet its demise. This Jupiter-like planet, called HIP 13044 b, is orbiting a star that used to be in another galaxy but that galaxy was swallowed by the Milky Way. While astronomers have never directly detected an exoplanet in another galaxy, this offers evidence that other galaxies host stars with planets, too. The star is nearing the end of its life and as it expands, could engulf the planet, just as our Sun will likely snuff out our own world. And somehow, this exoplanet has survived the first death throes of the star.
“The star is in the horizontal branch stage and it still has a planet, which is a glimmer of hope for those of us who worry about how our Solar System will look in 5 billion years,” said Markus Poessel, from the Max-Planck-Institut für Astronomie (MPIA) press office.
The star, HIP 13044, lies about 2,000 light-years from Earth in the southern constellation of Fornax (the Furnace). It is part of the so-called Helmi stream, a group of stars that originally belonged to a dwarf galaxy that was devoured by the Milky Way, probably about six to nine billion years ago.
The planet was detected using the radial velocity method — astronomers saw tiny telltale wobbles of the star caused by the gravitational tug of an orbiting companion. The instrument used was FEROS, a high-resolution spectrograph attached to the 2.2-meter MPG/ESO telescope at the La Silla Observatory in Chile.
“This discovery is very exciting,” says Rainer Klement from MPIA, who selected the target stars for this study. “For the first time, astronomers have detected a planetary system in a stellar stream of extragalactic origin. Because of the great distances involved, there are no confirmed detections of planets in other galaxies. But this cosmic merger has brought an extragalactic planet within our reach.”
This artist’s impression shows HIP 13044 b, an exoplanet orbiting a star that entered our galaxy, the Milky Way, from another galaxy. Credit: ESO/L. Calçada
HIP 13044 is in the red giant phase of stellar evolution, and this exoplanet must have survived the period when its host star expanded massively after exhausting the hydrogen fuel supply in its core . The star has now contracted again and is burning helium in its core. Until now, these horizontal branch stars have remained largely uncharted territory for planet-hunters.
“This discovery is part of a study where we are systematically searching for exoplanets that orbit stars nearing the end of their lives,” says Johny Setiawan, also from MPIA, who led the research. “This discovery is particularly intriguing when we consider the distant future of our own planetary system, as the Sun is also expected to become a red giant in about five billion years.”
Our sun is going down the same stellar evolutionary path as HIP 13044, so astronomers may be able to determine the fate of our solar system by studying the system.
Setiawan told Universe Today that he and his team will continue to observe HIP 13044 and other stars in the group to search for other planets. “It is of course difficult to follow how this particular star evolves over time,” he said, “but if you just observe other stars with different evolutionary phase, you can also complete the picture without waiting until this one single star evolves.”
How has this planet survived so far?
“The star is rotating relatively quickly for a horizontal branch star,” said Setiawan. “One explanation is that HIP 13044 swallowed its inner planets during the red giant phase, which would make the star spin more quickly.”
HIP 13044b probably once orbited much farther away from the star but spiraled inwards as the star began to spin faster.
The star also poses interesting questions about how giant planets form, as the star appears to contain very few elements heavier than hydrogen and helium — fewer than any other star known to host planets, and Setiawan said it is a puzzle how such a star could have formed a planet.
“There is indeed a possibility to form planets around metal-poor stars due to gravitational disk instability, which is an alternative to the core accretion model,” Setiawan said in an email. “But, for such a very metal poor star like HIP 13044, I am also not completely sure if the disk instability model can also explain the whole process. Still, it is probably the best explanation for this particular system.”
Six spectacular spiral galaxies are seen in a clear new light in images from ESO’s Very Large Telescope (VLT) at the Paranal Observatory in Chile. Credit: ESO
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Just like its ornithological namesake, the HAWK-I imager on the Very Large Telescope uses its piercing eyesight to hunt down its prey. But the High-Acuity Wide-field K-band Imager draws on its infrared vision to provide new insights into the spiral structures of galaxies. Today, ESO released six stunning new images of bright galaxies, showing exquisite detail with a clarity that is only possible by observing in the infrared.
Usually, dust in the arms of spiral galaxies blocks out much of the detail from our view, but observing in infrared light, much of the obscuring dust becomes transparent to its detectors. Compared to another VLT infrared camera called ISAAC, HAWK-I has sixteen times as many pixels to cover a much larger area of sky in one shot and, by using newer technology than ISAAC, it has a greater sensitivity to faint infrared radiation.
The six galaxies are part of a study of spiral structure led by Preben Grosbøl at ESO. Because HAWK-I can study galaxies stripped bare of the confusing effects of dust and glowing gas it is ideal for studying the vast numbers of stars that make up spiral arms, as well as helping astronomers to understand the complex and subtle ways in which the stars in these systems form into such perfect spiral patterns.
NGC 5247. Credit: ESO
The first image shows NGC 5247, a spiral galaxy dominated by two huge arms, located 60–70 million light-years away. The galaxy lies face-on towards Earth, thus providing an excellent view of its pinwheel structure. It lies in the zodiacal constellation of Virgo (the Maiden).
Messier 100, also known as NGC 4321. Credit: ESO
The galaxy in the second image is Messier 100, also known as NGC 4321, which lies about 55 million light-years from Earth in the Virgo Cluster of galaxies. It is an example of a “grand design” spiral galaxy — a class of galaxies with very prominent and well-defined spiral arms.
NGC 1300. Credit: ESO
The third image is of NGC 1300, a spiral galaxy with arms extending from the ends of a spectacularly prominent central bar. It is considered a prototypical example of barred spiral galaxies and lies at a distance of about 65 million light-years, in the constellation of Eridanus (the River).
NGC 4030. Credit: ESO
The spiral galaxy in the fourth image, NGC 4030, lies about 75 million light-years from Earth, in the constellation of Virgo.
NGC 2997. Credit: ESO
The fifth image, NGC 2997, is a spiral galaxy roughly 30 million light-years away in the constellation of Antlia. NGC 2997 is the brightest member of a group of galaxies of the same name in the Local Supercluster of galaxies. Our own Local Group, of which the Milky Way is a member, is itself also part of the Local Supercluster.
NGC 1232. Credit: ESO
Last but not least, NGC 1232 is a beautiful galaxy some 65 million light-years away in the constellation of Eridanus (the River). The galaxy is classified as an intermediate spiral galaxy — somewhere between a barred and an unbarred spiral galaxy.
Artist’s impression of a young galaxy accreting material. Credit: ESO/L. Calçada
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Until recently, it was thought the galactic equivalent of a motorway pile-up was the only way galaxies got bigger. But startling new evidence from a European team of astronomers suggests that violent galactic collisions are not the only way that galaxies evolve and grow, and instead there seems to be something else happening that has affected the majority of galaxies — a kinder, gentler action which is not quite so disruptive.
For some years, astronomers have struggled to understand why the mass of galaxies seems to have increased dramatically just a few billion years after the Big Bang. We know from observation that galaxies collide but this is an incredibly violent activity and one that is not particularly common.
A new study using the Very Large Telescope (VLT) at the European Southern Observatory (ESO), by a team led by Giovanni Cresci, looked for evidence that galaxies might be accreting material from the hydrogen and helium gas that filled the early Universe and permeates the space between the galaxies. We know that they are surrounded by halos of unseen material but Cresci’s team wanted to see if there was any evidence of material being sucked into the galaxy from the surrounding environment.
Their study focused on a group of distant galaxies which would represent those in the early Universe, about 2 billion years after the big bang, to see if they could detect any evidence of this gas accretion.
Using the SINFONI (Spectrograph for Integral Field Observation in the Near Infrared) attached to the VLT, Cresci and his team mapped the distribution of elements within the target galaxies. Their findings showed that instead of heavier elements being concentrated around the core as we find in today’s galaxies, the core was surprisingly abundant of the lighter elements hydrogen and helium. This can only be as a result of accretion of lighter elements from the surrounding area boosting the rate of star formation in the core. The accretion process itself relies on cool gas being transferred directly into the core of the galaxy.
“The primordial gas in the halo of galaxies, especially at great distances, is mostly shock heated and therefore very hot,” Cresci told Universe Today. “To be accreted it has to be cooled and this is not an efficient process. Recent theoretical models have shown that narrow streams of cold gas can form, and that they are able to penetrate the hot gas and to provide fresh gas to the centre of the galaxy. Unlike more destructive and violent mergers between galaxies, the streams are likely to keep the rotating disk configuration intact, although turbulent.”
This new discovery means astronomers have perhaps found an answer to a long standing question but with the major consequence of needing to rewrite our current theories of the evolution of the Universe.
