In this week’s edition of new unexplained astronomical phenomena, a team of astronomers led by Dr. Leigh Smith from Cambridge found a star 100 times larger than our sun that nearly disappears from the sky every few decades. They also have no idea why it does so.Continue reading “Astronomers Find a Blinking Star Near the Center of the Milky Way”
The Small Magellanic Cloud (SMC) is one of the Milky Way’s nearest companions (along with the Large Magellanic Cloud.) It’s visible with the naked eye in the southern hemisphere. A new image from the European Southern Observatory’s (ESO) Visible and Infrared Survey Telescope for Astronomy (VISTA) has peered through the clouds that obscure it and given us our biggest image ever of the dwarf galaxy.
The SMC contains several hundred million stars, is about 7,000 light years in diameter, and is about 200,000 light years away. It’s one of the most distant objects that we can see with the naked eye, and can only be seen from the southern hemisphere (and the lowest latitudes of the northern hemisphere.)
The SMC is a great target for studying how stars form because it’s so close to Earth, relatively speaking. But the problem is, its detail is obscured by clouds of interstellar gas and dust. So an optical survey of the Cloud is difficult.
But the ESO’s VISTA instrument is ideal for the task. VISTA is a near-infrared telescope, and infrared light is not blocked by the dust. VISTA was built at the ESO’s Paranal Observatory, in the Atacama Desert in Chile where it enjoys fantastic observing conditions. VISTA was designed to perform several surveys, including the Vista Magellanic Survey.
Explore the Zoomable image of the Small Magellanic Cloud. (You won’t be disappointed.)
The VISTA Magellanic Survey is focused on 3 main objectives:
- The study of stellar populations in the Magellanic Clouds
- The history of star formation in the Magellanic Clouds
- The three-dimensional structure of the Magellanic Clouds
An international team led by Stefano Rubele of the University of Padova has studied this image, and their work has produced some surprising results. VISTA has shown us that most of the stars in this image are much younger than stars in other neighbouring galaxies. It’s also shown us that the SMC’s morphology is that of a warped disc. These are only early results, and there’s much more work to be done analyzing the VISTA image.
The team presented their research in a paper titled “The VMC survey – XIV. First results on the look-back time star formation rate tomography of the Small Magellanic Cloud“, published in the journal Monthly Notices of the Royal Astronomical Society.
As the authors say in their paper, the SMC is a great target for study because of its “rich population of star clusters, associations, stellar pulsators, primary distance indicators, and stars in shortlived evolutionary stages.” In a way, we’re fortunate to have the SMC so close. But studying the SMC was difficult, until the VISTA came online with its infrared capabilities.
VISTA saw first light on December 11th, 2009. It’s time is devoted to systematic surveys of the sky. In its first five years, it has undertaken large surveys of the entire southern sky, and also studied small patches of the sky to discern extremely faint objects. The leading image in this article is from the Vista Magellanic Survey, a survey covering 184 square degrees of the sky, taking in both the Small Magellanic Cloud and the Large Magellanic Cloud, and their environment.
The image above is a portion of a new gigantic nine-gigapixel image from the VISTA infrared survey telescope at ESO’s Paranal Observatory of the central portion of the Milky Way Galaxy. The resolution of this image is so great, that if it was printed out in the resolution of a typical book, it would be 9 meters long and 7 meters tall! Click on the image to have access to an interactive, zoomable view of the more than 84 million stars that astronomers have now catalogued from this image. The huge dataset contains more than ten times more stars than previous studies and astronomers say it is a major step forward for the understanding of our home galaxy.
“By observing in detail the myriads of stars surrounding the centre of the Milky Way we can learn a lot more about the formation and evolution of not only our galaxy, but also spiral galaxies in general,” said Roberto Saito from Pontificia Universidad Católica de Chile, Universidad de Valparaíso, lead author of the study.
UPDATE: The image is also available on Gigapan, which provides a very smooth interface in which to explore and zoom around the image.
The dataset contains a treasure trove of information about the structure and content of the Milky Way. One interesting result revealed in the new data is the large number of faint red dwarf stars, which are prime candidates to search for small exoplanets using the transit method. Using this dataset, astronomers can also study the different physical properties of stars such as their temperatures, masses and ages.
To help analyze this huge catalogue, the brightness of each star is plotted against its color for about 84 million stars to create a color–magnitude diagram. This plot contains more than ten times more stars than any previous study and it is the first time that this has been done for the entire bulge.
This infrared view of the central part of the Milky Way from the VVV VISTA survey has been labelled to show a selection of the many nebulae and clusters in this part of the sky. Credit: ESO/VVV Consortium, Acknowledgement: Ignacio Toledo, Martin Kornmesser
“Each star occupies a particular spot in this diagram at any moment during its lifetime,” said Dante Minniti, also from Pontificia Universidad Catolica de Chile, Chile, co-author of the study. “Where it falls depends on how bright it is and how hot it is. Since the new data gives us a snapshot of all the stars in one go, we can now make a census of all the stars in this part of the Milky Way.”
Getting such a detailed view of the central region of our galaxy is not an easy task.
“Observations of the bulge of the Milky Way are very hard because it is obscured by dust,” said Minniti. “To peer into the heart of the galaxy, we need to observe in infrared light, which is less affected by the dust.”
The team used ESO’s 4.1-metre Visible and Infrared Survey Telescope for Astronomy (VISTA), which has a wide field of view. This new image is just one of six public surveys carried out with VISTA.
“One of the other great things about the VVV survey is that it’s one of the ESO VISTA public surveys. This means that we’re making all the data publicly available through the ESO data archive, so we expect many other exciting results to come out of this great resource,” said Saito.
“Ninety-six clusters of stars in the sky…. Ninety-six clusters of stars… You take one down and pass it around…” Do you need ninety-six new reasons to love astronomy? Then you’re going to want to hear about all the new discoveries the VISTA infrared survey telescope at ESO’s Paranal Observatory has made. Read on…
An international team of astronomers has taken observations to the next level with their discovery of 96 new star clusters which have been hidden behind the dusty cloak of interstellar matter. By utilizing sensitive infrared detectors and the world’s largest survey telescope, the intrepid crew set a new record for finding so many faint and small clusters at one time.
“This discovery highlights the potential of VISTA and the VVV survey for finding star clusters, especially those hiding in dusty star-forming regions in the Milky Way’s disc. VVV goes much deeper than other surveys,” says Jura Borissova, lead author of the study.
As astronomy enthusiasts well know, there’s more to a galactic cluster than just a pretty grouping of stars. Age, relation and motion all play a role. Some are loose groupings – held together by mutual gravitational attraction. Others are torn apart through interactions. Still others are in the process of formation, caught in the act with their gases showing. Yet all share a common denominator: they are around few hundred million years old and they are the by-product of a galaxy with active star formation.
“In order to trace the youngest star cluster formation we concentrated our search towards known star-forming areas. In regions that looked empty in previous visible-light surveys, the sensitive VISTA infrared detectors uncovered many new objects,” adds Dante Minniti, lead scientist of the VVV survey.
Once the grouping has been discovered, classification comes next. Through the use of specialized computer software, the team was able to separate foreground stars from genuine cluster components. Observation then came into play as stellar members were counted, sizes estimated, distances computed and extinction taken into consideration.
“We found that most of the clusters are very small and only have about 10–20 stars. Compared to typical open clusters, these are very faint and compact objects — the dust in front of these clusters makes them appear 10,000 to 100 million times fainter in visible light. It’s no wonder they were hidden,” explains Radostin Kurtev, another member of the team.
Since antiquity only 2500 open clusters have been found in the Milky Way, but astronomers estimate there might be as many as 30,000 still hiding behind the dust and gas. That means these new 96 open clusters could be only the very beginning of a host of new discoveries. “We’ve just started to use more sophisticated automatic software to search for less concentrated and older clusters. I am confident that many more are coming soon,” adds Borissova.
Until then we’ll just “Take one down and pass it around… 29,999 clusters of stars in the sky.”
Original Story Source: ESO Press Release.
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.
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.
ESO’s VISTA telescope has begun a new survey of the Magellanic Cloud, and this spectacular image of the Tarantula Nebula is a taste of great things to come from this near-infrared scan of the more interesting galaxies in our neighborhood. This panoramic near-infrared view captures the nebula itself in great detail as well as the rich surrounding area of sky. “This view is of one of the most important regions of star formation in the local Universe — the spectacular 30 Doradus star-forming region, also called the Tarantula Nebula,” said the leader of the survey team, Maria-Rosa Cioni from the University of Hertfordshire. “At its core is a large cluster of stars called RMC 136, in which some of the most massive stars known are located.”
VISTA is a new survey telescope at the Paranal Observatory in Chile, and is equipped with a huge camera that detects light in the near-infrared part of the spectrum, revealing a wealth of detail about astronomical objects that gives us insight into the inner workings of astronomical phenomena. Near-infrared light has a longer wavelength than visible light, fortunately, it can pass through much of the dust that would normally obscure the views that our eyes can see. This makes it particularly useful for studying objects such as young stars that are still enshrouded in the gas and dust clouds from which they formed. Another powerful aspect of VISTA is the large area of the sky that its camera can capture in each shot.
The VISTA Magellanic Cloud Survey is one of six huge near-infrared surveys of the southern sky that will take up most of the first five years of operations of VISTA.
This project will scan a vast area — 184 square degrees of the sky (corresponding to almost one thousand times the apparent area of the full Moon) including our neighboring galaxies the Large and Small Magellanic Clouds. The end result will be a detailed study of the star formation history and three-dimensional geometry of the Magellanic system.
“The VISTA images will allow us to extend our studies beyond the inner regions of the Tarantula into the multitude of smaller stellar nurseries nearby, which also harbor a rich population of young and massive stars,” said Chris Evans who is part of the VMC team. “Armed with the new, exquisite infrared images, we will be able to probe the cocoons in which massive stars are still forming today, while also looking at their interaction with older stars in the wider region.”
The wide-field image shows a host of different objects. The bright area above the centre is the Tarantula Nebula itself, with the RMC 136 cluster of massive stars in its core. To the left is the NGC 2100 star cluster. To the right is the tiny remnant of the supernova SN1987A (eso1032). Below the centre are a series of star-forming regions including NGC 2080 — nicknamed the “Ghost Head Nebula” — and the NGC 2083 star cluster.
See more images, zoomable images, and movies of the Tarantula Nebula at the ESO website.
The new VISTA telescope at the Paranal Observatory in Chile (the Visible and Infrared Survey Telescope for Astronomy) has captured a great new image of the Sculptor Galaxy (NGC 253), and this video allows you to zoom in for a closer look. The sequence starts with a wide view of the southern sky far from the Milky Way. Only a few stars are visible, but then VISTA brings us in closer where the view shifts to the very detailed new infrared image of NGC 253 provided by the new telescope at Paranal. By observing in infrared light VISTA’s view is less affected by dust and reveals a myriad of cooler stars as well as a prominent bar of stars across the central region. The VISTA image provides much new information on the history and development of the galaxy. See the still image below.
The Sculptor Galaxy (NGC 253) lies in the constellation of the same name and is one of the brightest galaxies in the sky. It is prominent enough to be seen with good binoculars and was discovered by Caroline Herschel from England in 1783. NGC 253 is a spiral galaxy that lies about 13 million light-years away. It is the brightest member of a small collection of galaxies called the Sculptor Group, one of the closest such groupings to our own Local Group of galaxies. Part of its visual prominence comes from its status as a starburst galaxy, one in the throes of rapid star formation. NGC 253 is also very dusty, which obscures the view of many parts of the galaxy. Seen from Earth, the galaxy is almost edge on, with the spiral arms clearly visible in the outer parts, along with a bright core at its center.
Learn more about this image and the VISTA telescope at the ESO website.
Oh-oh-oh Orion! The new VISTA (Visible and Infrared Survey Telescope for Astronomy) infrared survey telescope has used its huge field of view to show the full splendor of the Orion Nebula. With its infrared eyes, it has peered deeply into dusty regions that are normally hidden to expose the curious behavior of the very active young stars buried there.
VISTA is the latest addition to ESO’s Paranal Observatory. It is the largest survey telescope in the world and is dedicated to mapping the sky at infrared wavelengths. The large (4.1-metre) mirror, wide field of view and very sensitive detectors make VISTA a unique instrument. This dramatic new image of the Orion Nebula illustrates VISTA’s remarkable powers.
The Orion Nebula is about 1,350 light-years from Earth. Although spectacular when seen through an ordinary telescope, what can be seen using visible light is only a small part of a cloud of gas in which stars are forming. Most of the action is deeply embedded in dust clouds and to see what is really happening astronomers need to use telescopes with detectors sensitive to the longer wavelength radiation that can penetrate the dust. VISTA has imaged the Orion Nebula at wavelengths about twice as long as can be detected by the human eye.
On the upper-left, the central region of VISTA’s view of the Orion Nebula is shown, centered on the four dazzling stars of the Trapezium. A rich cluster of young stars can be seen here that is invisible in normal, visible light images. In the lower-right panel the part of the nebula to the north of the center is shown. Here there are many young stars embedded in the dust clouds that are only apparent because their infrared glow can penetrate the dust and be detected by the VISTA camera. Many outflows, jets and other interactions from young stars are apparent, seen in the infrared glow from molecular hydrogen and showing up as red blobs. On the upper-right, a region to the west of center is shown. Here the fierce ultraviolet light from the Trapezium is sculpting the gas clouds into curious wavy shapes. A distant edge-on spiral galaxy is also seen shining right through the nebula. At the lower-left a region south of the center is shown. Each extract covers a region of sky about nine arcminutes across.
All these features are of great interest to astronomers studying the birth and youth of stars.