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The Home of Humanity Is Here and In This Tiny Spec on the Universe: The Milky Way Galaxy: Why Are You All Warped Up

 

 

 

|| Wednesday: March 04: 2020 || ά. Astronomers have pondered for years why our galaxy, the Milky Way, is warped. Data from the European Space Agency:ESA’s star-mapping satellite Gaia suggests that the distortion might be caused by an on-going collision with another, smaller, galaxy, which sends ripples through the galactic disc like a rock thrown into water.

Astronomers have known since the late 1950s that the Milky Way’s disc, where most of its hundreds of billions of stars reside, is not flat but somewhat curved upwards on one side and downwards on the other. For years, they debated what is causing this warp. They proposed various theories, including, the influence of the intergalactic magnetic field or the effects of a dark matter halo, a large amount of unseen matter, that is expected to surround galaxies. If, such a halo had an irregular shape, its gravitational force could bend the galactic disc.

With its unique survey of more than one billion stars in our galaxy, Gaia might hold the key to solving this mystery. A team of scientists, using data from the second Gaia data release, has now confirmed previous hints that this warp is not static but changes its orientation over time. Astronomers call this phenomenon precession and it could be compared to the wobble of a spinning top as its axis rotates.

Moreover, the speed at which the warp precesses is much faster than expected, faster than the intergalactic magnetic field or the dark matter halo would allow. That suggests the warp must be caused by something else. Something more powerful, like a collision with another galaxy.

“We measured the speed of the warp by comparing the data with our models. Based on the obtained velocity, the warp would complete one rotation around the centre of the Milky Way in 600 to 700 million years.” says Ms Eloisa Poggio of the Turin Astrophysical Observatory, Italy, who is the Lead Author of the Study, published in Nature Astronomy. “That’s much faster than what we expected, based on predictions from other models, such as, those looking at the effects of the non-spherical halo.”

The warp’s speed is, however, slower than the speed at which the stars themselves orbit the galactic centre. The Sun, for example, completes one rotation in about 220 million years. Such insights were only possible due to the unprecedented ability of the Gaia mission to map our galaxy, the Milky Way, in three-D, by accurately determining positions of more than one billion stars in the sky and estimating their distance from us. The flying saucer-like telescope, also, measures the velocities at which individual stars move in the sky, allowing astronomers to ‘play’ the movie of the Milky Way’s history back- and forward in time over millions of years.

“It’s like having a car and trying to measure the velocity and direction of travel of this car over a very short period of time and, then, based on those values, trying to model the past and future trajectory of the car.” says Mr Ronald Drimmel, a Research Astronomer at the Turin Astrophysical Observatory and Co-author of the Paper. “If, we make such measurements for many cars, we could model the flow of traffic. Similarly, by measuring the apparent motions of millions of stars across the sky we can model large scale processes such as the motion of the warp.”

The astronomers do not yet know which galaxy might be causing the ripple nor when the collision started. One of the contenders is Sagittarius, a dwarf galaxy orbiting the Milky Way, which is believed to have burst through the Milky Way’s galactic disc several times in the past. Astronomers think that Sagittarius will be gradually absorbed by the Milky Way, a process, which is already underway.

“With Gaia, for the first time, we have a large amount of data on a vast amount stars, the motion of which is measured so precisely that we can try to understand the large scale motions of the galaxy and model its formation history.” says ESA’s Gaia Deputy Project Scientist Mr Jos de Bruijne. “This is something unique. This really is the Gaia revolution.”

“The Sun is at the distance of 26 000 light years from the galactic centre where the amplitude of the warp is very small.” Ms Eloisa says. “Our measurements were, mostly, dedicated to the outer parts of the galactic disc, out to 52 000 light years from the galactic centre and beyond.”

Gaia previously uncovered evidence of collisions between the Milky Way and other galaxies in the recent and distant past, which can still be observed in the motion patterns of large groups of stars billions of years after the events occurred.

Meanwhile, the satellite, currently in the sixth year of its mission, keeps scanning the sky and a Europe-wide consortium is busy processing and analysing the data that keeps flowing towards Earth. Astronomers across the world are looking forward to the next two Gaia data releases, planned for later in 2020 and in the second half of 2021, respectively, to tackle further mysteries of the galaxy we call home.

The Paper: Evidence of a dynamically evolving Galactic warp: by E. Poggio et al: Published in Nature Astronomy.

::: Credit: The galactic disc of the Milky Way, our galaxy, is not flat but warped upwards on one side and downwards on the other. Data from ESA's galaxy-mapping spacecraft Gaia provides new insights into the behaviour of the warp and its possible origins The two smaller galaxies in the lower right corner are the Large and Small Magellanic Clouds, two satellite galaxies of the Milky Way: Stefan Payne-Wardenaar: : Robert Gendler:ESO

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Astronomers Detect Helium in the Atmosphere of Exoplanet WASP-107b: The First Time An Exoplanet is Found to Have Helium in Its Atmosphere

 

 

|| May 02: 2018 || ά. Astronomers, using the NASA:ESA Hubble Space Telescope, have detected helium in the atmosphere of the exoplanet WASP-107b. This is the first time this element has been detected in the atmosphere of a planet outside the Solar System. The discovery demonstrates the ability to use infrared spectra to study exoplanet extended atmospheres. The international team of astronomers, led by Ms Jessica Spake, a PhD student at the University of Exeter in the UK, used Hubble’s Wide Field Camera three to discover helium in the atmosphere of the exoplanet WASP-107b.

Ms Spake explains the importance of the discovery, “Helium is the second-most common element in the Universe after hydrogen. It is, also, one of the main constituents of the planets Jupiter and Saturn in our Solar System. However, up until now helium had not been detected on exoplanets despite searches for it.” The research team made the detection by analysing the infrared spectrum of the atmosphere of WASP-107b. Previous detections of extended exoplanet atmospheres have been made by studying the spectrum at ultraviolet and optical wavelengths; this detection, therefore, demonstrates that exoplanet atmospheres can, also, be studied at longer wavelengths.

“The strong signal from helium we measured demonstrates a new technique to study upper layers of exoplanet atmospheres in a wider range of planets.” says Ms Spake “Current methods, which use ultraviolet light, are limited to the closest exoplanets. We know there is helium in the Earth’s upper atmosphere and this new technique, may, help us to detect atmospheres around Earth-sized exoplanets, which is very difficult with current technology.”

WASP-107b is one of the lowest density planets known: While the planet is about the same size as Jupiter, it has only 12% of Jupiter’s mass. The exoplanet is about 200 light-years from Earth and takes less than six days to orbit its host star.

The amount of helium detected in the atmosphere of WASP-107b is so large that its upper atmosphere must extend tens of thousands of kilometres out into space. This, also, makes it the first time that an extended atmosphere has been discovered at infrared wavelengths.

Since its atmosphere is so extended, the planet is losing a significant amount of its atmospheric gases into space, between ~0.1-4% of its atmosphere’s total mass every billion years. As far back as the year 2000, it was predicted that helium would be one of the most readily-detectable gases on giant exoplanets but until now, searches were unsuccessful. Mr David Sing, Co-author of the stud,  also, from the University of Exeter, said, “Our new method, along with future telescopes such as the NASA:ESA:CSA James Webb Space Telescope, will allow us to analyse atmospheres of exoplanets in far greater detail than ever before.”

The measurement of an exoplanet’s atmosphere is performed when the planet passes in front of its host star. A tiny portion of the star’s light passes through the exoplanet’s atmosphere, leaving detectable fingerprints in the spectrum of the star. The larger the amount of an element present in the atmosphere, the easier the detection becomes.

Stellar radiation has a significant effect on the rate at which a planet’s atmosphere escapes. The star WASP-107 is highly active, supporting the atmospheric loss. As the atmosphere absorbs radiation it heats up, so the gas rapidly expands and escapes more quickly into space. The Hubble Space Telescope is a project of international cooperation between ESA and NASA.

The study, 'Helium in the eroding atmosphere of an exoplanet' was published in Nature.

The international team of astronomers in this study consists of J. J. Spake, University of Exeter, UK, D. K. Sing, University of Exeter, UK, Johns Hopkins University, USA, T. M. Evans, University of Exeter, UK, A. Oklopčić, Harvard-Smithsonian Centre for Astrophysics, USA, V. Bourrier, Observatoire de l’Université de Genève, Switzerland, L. Kreidberg, Harvard Society of Fellows, USA, Harvard-Smithsonian Centre for Astrophysics, USA, B. V. Rackham, University of Arizona, USA, J. Irwin, Harvard-Smithsonian Centre for Astrophysics, USA, D. Ehrenreich, (Observatoire de l’Université de Genève, Switzerland, A. Wyttenbach, Observatoire de l’Université de Genève, Switzerland, H. R. Wakeford, Space Telescope Science Institute, USA, Y. Zhou, University of Arizona, USA, K. L. Chubb, University College London, UK, N. Nikolov, University of Exeter, UK, J. Goyal, University of Exeter, UK, G. W. Henry, Tennessee State University, USA, M. H. Williamson, Tennessee State University, USA, S. Blumenthal, Space Telescope Science Institute, USA, D. Anderson, Keele University, UK, C. Hellier, Keele University, UK, D. Charbonneau, Harvard-Smithsonian Centre for Astrophysics, USA, S. Udry, Observatoire de l’Université de Genève, Switzerland and N. Madhusudhan, University of Cambridge, UK.

Caption: The exoplanet WASP-107b is a gas giant, orbiting a highly active K-type main sequence star. The star is about 200 light-years from Earth. Using spectroscopy, scientists were able to find helium in the escaping atmosphere of the planet, the first detection of this element in the atmosphere of an exoplanet: Image: ESA:Hubble, NASA:M. Kornmesser ::: ω.

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Gaia's Job Is Not Done Yet But Here's an Impressive Census of Over One Billion Stars in Our Milky Way: Another Few Hundred Billions to Go

|| April 29: 2018: UCL News ||ά. The positions and distances of over one billion stars in our Milky Way Galaxy have been released by the European Space Agency Gaia mission involving UCL researchers, creating the first three-D census of our home galaxy and opening a new window on the Universe. The data release allows astronomers to map the true three-D structure of our galaxy with unprecedented precision by providing information about 600 times more stars than previously available.

It covers a volume of the Milky Way 1000 times larger than Gaia’s own first data release and with precision one hundred times improved. Gaia aims to produce the most detailed map ever made of the galaxy and final results are expected in the early 2020s. Today’s results allow improved study of, almost, all branches of astronomy, helping us understand: how the Solar System formed; how stars evolve; how the Milky Way assembled; where dark matter is distributed in the Galaxy and the distance scale in the Universe.

“We use Gaia to measure the Milky Way, star by star, where they were born, how they were generated, what their temperatures are and their radial velocity. It’s given us direct evidence of the rotation of our galaxy and opens the door to many more detailed studies on the way other disk galaxies evolve.” said Professor Mark Cropper, Gaia Team Lead at UCL Mullard Space Science Laboratory:UCL MSSL.

The data set contains information on 01.7 billion stars, quasars, asteroids and galaxies. This includes precise measures of distance and motion across the sky, brightness and colours for 01.3 billion stars, radial velocities for seven million stars, stellar parameters for some 100 million stars, variability over time for 550,000 stars and accurate orbital data for 14,000 asteroids.

UCL Mullard Space Science Laboratory has contributed significantly to Gaia for 17 years by testing and calibrating each of the 106 electronic detectors used to capture much of the data shared today. It’s, also, taken a critical role in the development of Gaia’s advanced Radial Velocity Spectrometer:RVS and processing the data from it.

“So far, we’ve calculated the radial velocities of over seven million stars from data of nearly 20 billion separate spectra, which is a demanding but worthwhile process! These numbers are only set to increase, most likely, up to 100 million stars, as we analyse more distant, fainter stars and we eagerly anticipate what else Gaia uncovers.” said Professor Cropper.

Rather than keeping the results for their own science interests, Gaia’s team of hundreds of engineers and scientists across Europe, process and calibrate the data for others to use. Today, UCL scientists and engineers have published several papers, supported by funding from the UK Space Agency and UK Science and Technology Facilities Council, part of UKRI, which provide analysis of Gaia data for the community and illustrate the remarkable accuracy and volume of the data.

One paper, published in Astronomy and Astrophysics and co-authored by Dr George Seabroke at UCL MSSL, illustrates the power of using Gaia’s spectroscopic data to map the motion of objects in the disc of the Milky Way.

“The full scientific exploitation of Gaia’s first data release was limited by the number of stars with accurate distances from Gaia and radial velocities from ground-based surveys, which was less than 400,000. Now, Gaia’s second data release includes its own radial velocities, we have used these data to create the most detailed ever map of how stars are moving.

Using this, we discovered a new global arrangement of stars for the first time, in which stars are organised in thin substructures with the shape of circular arches in velocity space. It is a vital clue to how the Galactic disc formed and is still evolving!” said Dr Seabroke.

“The combination of all these unprecedented measures provides the information for astronomers to take the next big steps in mapping the formation history and evolutions of stars and our Milky Way Galaxy. There is hardly a branch of astrophysics which will not be revolutionised by Gaia data. The global community will advance our understanding of what we see, where it came from, what it is made from, how it is changing.” concluded Professor Gerry Gilmore, Cambridge University, UK Principal Investigator for the UK participation in the Gaia Data Processing and Analysis Consortium.

The data set released includes information collected over 22 months and the spacecraft has fuel for another six-seven years operation, allowing a 10-year operational lifetime. Gaia continues to observe and the team eagerly awaits what else it will discover.

Dr Graham Turnock, Chief Executive of the UK Space Agency, said, “We’re working with industry and academia to support cutting-edge science, that will lead to new discoveries about our Galaxy. The UK involvement in this exciting mission shows that our academics and engineers are world leaders in the space sector. As part of ESA we will continue to be at the forefront of research and deeply involved in missions such as ExoMars, with its Airbus-built rover, and the BepiColombo mission to Mercury.'' ::: ω.

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Gaia: What Do You Do All Day and For Years Some Five: I Survey the Heavens That Your Eyes Can Never Do So That You May Form the Eyeonium Where You Would See the Refection of Your Earthly Garden That Feeds on the Lunaarian Blues

|| April 11: 2017 || ά. This may look like a brightly decorated Easter egg wrapping, but it actually represents how ESA’s Gaia satellite scanned the sky during its first 14 months of science operations, between July 2014 and September 2015. The oval represents the celestial sphere, with the colours indicating how frequently the different portions of the sky were scanned. Blue represents the regions scanned most frequently in that time period; the lighter colours lesser so.

The satellite scans great circles on the sky, with each lasting about six hours. During the first month, the scanning procedure was such that the ecliptic poles were always included. This meant that Gaia observed the stars in those regions many times, providing an invaluable database for the initial calibration of the observations. Then, the satellite started its main survey, scanning in such a way to achieve the best possible coverage of the whole sky.

These initial 14 months provided the first catalogue of the brightness and precise position of more than a billion stars, the largest all-sky survey of celestial objects to date.

Over its five-year mission, Gaia will survey one billion stars in our Galaxy and local galactic neighbourhood, measuring their position and motion at unprecedented accuracy, in order to build the most precise three-D map of the Milky Way and answer questions about its structure, origin and evolution. ω.

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Look: Little Gem

|| September 10: 2016 || ά. A fossilised remnant of the early Milky Way harbouring stars of hugely different ages has been revealed by an international team of astronomers. This stellar system resembles a globular cluster, but is like no other cluster known. It contains stars remarkably similar to the most ancient stars in the Milky Way and bridges the gap in understanding between our galaxy’s past and its present.

Terzan Five 19000 light-years from Earth, has been classified as a globular cluster for the forty-odd years since its detection. Now, an Italian-led team of astronomers have discovered that Terzan Five is like no other globular cluster known. The team scoured data from the Advanced Camera for Surveys and the Wide Field Camera Three on board Hubble, as well as from a suite of other ground-based telescopes. They found compelling evidence that there are two distinct kinds of stars in Terzan Five which not only differ in the elements they contain, but have an age-gap of roughly seven billion years.

The ages of the two populations indicate that the star formation process in Terzan Five was not continuous, but was dominated by two distinct bursts of star formation. “This requires the Terzan Five ancestor to have large amounts of gas for a second generation of stars and to be quite massive. At least 100 million times the mass of the Sun,” explains Davide Massari, co-author of the study, from INAF, Italy, and the University of Gröningen, Netherlands.

Its unusual properties make Terzan Five the ideal candidate for a living fossil from the early days of the Milky Way. Current theories on galaxy formation assume that vast clumps of gas and stars interacted to form the primordial bulge of the Milky Way, merging and dissolving in the process.

“We think that some remnants of these gaseous clumps could remain relatively undisrupted and keep existing embedded within the galaxy,” explains Francesco Ferraro from the University of Bologna, Italy, and lead author of the study. “Such galactic fossils allow astronomers to reconstruct an important piece of the history of our Milky Way.”

While the properties of Terzan Five are uncommon for a globular cluster, they are very similar to the stellar population which can be found in the galactic bulge, the tightly packed central region of the Milky Way. These similarities could make Terzan Five a fossilised relic of galaxy formation, representing one of the earliest building blocks of the Milky Way.

This assumption is strengthened by the original mass of Terzan Five necessary to create two stellar populations: a mass similar to the huge clumps which are assumed to have formed the bulge during galaxy assembly around 12 billion years ago. Somehow Terzan Five has managed to survive being disrupted for billions of years, and has been preserved as a remnant of the distant past of the Milky Way.

“Some characteristics of Terzan Five resemble those detected in the giant clumps we see in star-forming galaxies at high-redshift, suggesting that similar assembling processes occurred in the local and in the distant Universe at the epoch of galaxy formation,“ continues Ferraro.

Hence, this discovery paves the way for a better and more complete understanding of galaxy assembly. “Terzan Five could represent an intriguing link between the local and the distant Universe, a surviving witness of the Galactic bulge assembly process,” explains Ferraro while commenting on the importance of the discovery. The research presents a possible route for astronomers to unravel the mysteries of galaxy formation, and offers an unrivalled view into the complicated history of the Milky Way. ω.

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The One and the Only Jupiter: Although There are Billion or More Jupiter-like Planets Coursing Their Orbits Around Other Suns Across the Milky Way

|| August 26: 2016: Pat Brennan: NASA || ά. Our galaxy the Milky Way is home to a bewildering variety of Jupiter-like worlds: hot ones, cold ones, giant versions of our own giant, pint-sized pretenders only half as big around. Astronomers say that in our galaxy alone, a billion or more such Jupiter-like worlds could be orbiting stars other than our sun. And we can use them to gain a better understanding of our solar system and our galactic environment, including the prospects for finding life.

It turns out the inverse is also true, we can turn our instruments and probes to our own backyard, and view Jupiter as if it were an exoplanet to learn more about those far-off worlds. The best-ever chance to do this is now, with Juno, a NASA probe the size of a basketball court, which arrived at Jupiter in July to begin a series of long, looping orbits around our solar system's largest planet. Juno is expected to capture the most detailed images of the gas giant ever seen. And with a suite of science instruments, Juno will plumb the secrets beneath Jupiter's roiling atmosphere.

It will be a very long time, if ever, before scientists who study exoplanets, planets orbiting other stars, get the chance to watch an interstellar probe coast into orbit around an exo-Jupiter, dozens or hundreds of light-years away. But if they ever do, it's a safe bet the scene will summon echoes of Juno. "The only way we're going to ever be able to understand what we see in those extrasolar planets is by actually understanding our system, our Jupiter itself," said David Ciardi, an astronomer with NASA's Exoplanet Science Institute:NExSci at Caltech.

Not all Jupiters are created equal

Juno's detailed examination of Jupiter could provide insights into the history, and future, of our solar system. The tally of confirmed exoplanets so far includes hundreds in Jupiter's size-range, and many more that are larger or smaller. The so-called hot Jupiters acquired their name for a reason: They are in tight orbits around their stars that make them sizzling-hot, completing a full revolution, the planet's entire year, in what would be a few days on Earth. And they're charbroiled along the way.

But why does our solar system lack a "hot Jupiter?" Or is this, perhaps, the fate awaiting our own Jupiter billions of years from now, could it gradually spiral toward the sun, or might the swollen future sun expand to engulf it? Not likely, Ciardi says; such planetary migrations probably occur early in the life of a solar system. "In order for migration to occur, there needs to be dusty material within the system," he said. "Enough to produce drag. That phase of migration is long since over for our solar system." Jupiter itself might already have migrated from farther out in the solar system, although no one really knows, he said.

Looking back in time

If Juno's measurements can help settle the question, they could take us a long way toward understanding Jupiter's influence on the formation of Earth, and, by extension, the formation of other "Earths" that might be scattered among the stars."Juno is measuring water vapour in the Jovian atmosphere," said Elisa Quintana, a research scientist at the NASA Ames Research Centre in Moffett Field, California. "This allows the mission to measure the abundance of oxygen on Jupiter. Oxygen is thought to be correlated with the initial position from which Jupiter originated."

If Jupiter's formation started with large chunks of ice in its present position, then it would have taken a lot of water ice to carry in the heavier elements which we find in Jupiter. But a Jupiter that formed farther out in the solar system, then migrated inward, could have formed from much colder ice, which would carry in the observed heavier elements with a smaller amount of water. If Jupiter formed more directly from the solar nebula, without ice chunks as a starter, then it should contain less water still. Measuring the water is a key step in understanding how and where Jupiter formed.

That's how Juno's microwave radiometer, which will measure water vapour, could reveal Jupiter's ancient history. "If Juno detects a high abundance of oxygen, it could suggest that the planet formed farther out," Quintana said. A probe dropped into Jupiter by NASA’s Galileo spacecraft in 1995 found high winds and turbulence, but the expected water seemed to be absent. Scientists think Galileo's one-shot probe just happened to drop into a dry area of the atmosphere, but Juno will survey the entire planet from orbit.

The chaotic early years

Where Jupiter formed, and when, also could answer questions about the solar system's "giant impact phase," a time of crashes and collisions among early planet-forming bodies that eventually led to the solar system we have today. Our solar system was extremely accident-prone in its early history, perhaps not quite like billiard balls caroming around, but with plenty of pileups and fender-benders.

"It definitely was a violent time," Quintana said. "There were collisions going on for tens of millions of years. For example, the idea of how the moon formed is that a proto-Earth and another body collided; the disk of debris from this collision formed the moon. And some people think Mercury, because it has such a huge iron core, was hit by something big that stripped off its mantle; it was left with a large core in proportion to its size."

Part of Quintana's research involves computer modeling of the formation of planets and solar systems. Teasing out Jupiter's structure and composition could greatly enhance such models, she said. Quintana already has modeled our solar system's formation, with Jupiter and without, yielding some surprising findings.

"For a long time, people thought Jupiter was essential to habitability because it might have shielded Earth from the constant influx of impacts [during the solar system's early days] which could have been damaging to habitability," she said. "What we've found in our simulations is that it's almost the opposite. When you add Jupiter, the accretion times are faster and the impacts onto Earth are far more energetic. Planets formed within about 100 million years; the solar system was done growing by that point," Quintana said.

"If you take Jupiter out, you still form Earth, but on timescales of billions of years rather than hundreds of millions. Earth still receives giant impacts, but they're less frequent and have lower impact energies," she said.

Getting to the core

Another critical Juno measurement that could shed new light on the dark history of planetary formation is the mission's gravity science experiment. Changes in the frequency of radio transmissions from Juno to NASA's Deep Space Network will help map the giant planet's gravitational field. Knowing the nature of Jupiter's core could reveal how quickly the planet formed, with implications for how Jupiter might have affected Earth's formation.

And the spacecraft's magnetometers could yield more insight into the deep internal structure of Jupiter by measuring its magnetic field. "We don't understand a lot about Jupiter's magnetic field," Ciardi said. "We think it's produced by metallic hydrogen in the deep interior. Jupiter has an incredibly strong magnetic field, much stronger than Earth's."

Mapping Jupiter's magnetic field also might help pin down the plausibility of proposed scenarios for alien life beyond our solar system. Earth's magnetic field is thought to be important to life because it acts like a protective shield, channeling potentially harmful charged particles and cosmic rays away from the surface.

"If a Jupiter-like planet orbits its star at a distance where liquid water could exist, the Jupiter-like planet itself might not have life, but it might have moons which could potentially harbor life," he said. An exo-Jupiter’s intense magnetic field could protect such life forms, he said. That conjures visions of Pandora, the moon in the movie "Avatar" inhabited by 10-foot-tall humanoids who ride massive, flying predators through an exotic alien ecosystem.

Juno's findings will be important not only to understanding how exo-Jupiters might influence the formation of exo-Earths, or other kinds of habitable planets. They'll also be essential to the next generation of space telescopes that will hunt for alien worlds. The Transiting Exoplanet Survey Satellite:TESS will conduct a survey of nearby bright stars for exoplanets beginning in June 2018, or earlier. The James Webb Space Telescope, expected to launch in 2018, and WFIRST:Wide-Field Infrared Survey Telescope, with launch anticipated in the mid-2020s, will attempt to take direct images of giant planets orbiting other stars.

"We're going to be able to image planets and get spectra," or light profiles from exoplanets that will reveal atmospheric gases, Ciardi said. Juno's revelations about Jupiter will help scientists to make sense of these data from distant worlds. "Studying our solar system is about studying exoplanets," he said. "And studying exoplanets is about studying our solar system. They go together."

Preston Dyches: Jet Propulsion Laboratory, Pasadena, Calif. 818-354-7013:preston.dyches at jpl.nasa.gov

Written by Pat Brennan: NASA Exoplanet Programme

Editor: Tony Greicius:NASA: ω.

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The Little Fox in Whose Heart Flourish Giant Stars

|| May 24 : 2016 || ά. New stars are the lifeblood of our Galaxy, and there is enough material revealed by this Herschel infrared image to build stars for millions of years to come. Situated 8000 light-years away in the constellation Vulpecula – latin for little fox – the region in the image is known as Vulpecula OB1. It is a ‘stellar association’ in which a batch of truly giant ‘OB’ stars is being born.

The vast quantities of ultraviolet and other radiation emitted by these stars is compressing the surrounding cloud, causing nearby regions of dust and gas to begin the collapse into more new stars. In time, this process will ‘eat’ its way through the cloud, transforming some of the raw material into shining new stars.

The image was obtained as part of Herschel’s Hi-GAL key-project. This used the infrared space observatory’s instruments to image the entire galactic plane in five different infrared wavelengths.
These wavelengths reveal cold material, most of it between -220ºC and -260ºC. None of it can be seen at ordinary optical wavelengths, but this infrared view shows astronomers a surprising amount of structure in the cloud’s interior.

The surprise is that the Hi-GAL survey has revealed a spider’s web of filaments that stretches across the star-forming regions of our Galaxy. Part of this vast network can be seen in this image as a filigree of red and orange threads.

At visual wavelengths, the OB association is linked to a star cluster catalogued as NGC 6823. It was discovered by William Herschel in 1785 and contains 50–100 stars. A nebula emitting visible light, catalogued as NGC 6820, is also part of this multi-faceted star-forming region.

The giant stars at the heart of Vulpecula OB1 are some of the biggest in the Galaxy. Containing dozens of times the mass of the Sun, they have short lives, astronomically speaking, because they burn their fuel so quickly.

At an estimated age of two million years, they are already well through their lifespans. When their fuel runs out, they will collapse and explode as supernovas. The shock this will send through the surrounding cloud will trigger the birth of even more stars, and the cycle will begin again. ω.

Star Cluster Bursts into Life

|| May 21: 2016 || ά. The star-forming region NGC 3603 - seen here in the latest Hubble Space Telescope image - contains one of the most impressive massive young star clusters in the Milky Way. Bathed in gas and dust the cluster formed in a huge rush of star formation thought to have occurred around a million years ago. The hot blue stars at the core are responsible for carving out a huge cavity in the gas seen to the right of the star cluster in NGC 3603's centre. ω.

Exodoubt: Exomoons or Exoplanets? Cannot Be Both Yet Cannot Be Confirmed

|| May 06: 2016 || Researchers have detected the first "exomoon" candidate -- a moon orbiting a planet that lies outside our solar system. Using a technique called "microlensing," they observed what could be either a moon and a planet -- or a planet and a star. This artist's conception depicts the two possibilities, with the planet/moon pairing on the left, and star/planet on the right. If the moon scenario is true, the moon would weigh less than Earth, and the planet would be more massive than Jupiter.

The scientists can't confirm the results partly because microlensing events happen once, due to chance encounters. The events occur when a star or planet happens to pass in front of a more distant star, causing the distant star to brighten. If the passing object has a companion -- either a planet or moon -- it will alter the brightening effect. Once the event is over, it is possible to study the passing object on its own. But the results would still not be able to distinguish between a planet/moon duo and a faint star/planet. Both pairings would be too dim to be seen.

In the future, it may be possible to enlist the help of multiple telescopes to watch a lensing event as it occurs, and confirm the presence of exomoons.

Separate views

( Editor: Tony Greicius: NASA)
 

The Galactic War and Peace and Cat's Paws

|| April 26: 2016 ||  This new video from ESA’s Herschel space observatory reveals in stunning detail the intricate pattern of gas, dust and star-forming hubs along the plane of our Galaxy, the Milky Way.

Against the diffuse background of the interstellar material, a wealth of bright spots, wispy filaments and bubbling nebulas emerge, marking the spots where stars are being born in the Galaxy.

The video was compiled by stitching together several hundred hours of Herschel observations. It spans a vast portion – almost 40% – of the plane of the Milky Way, where most of the stars in the Galaxy form and reside.

 Our disc-shaped Galaxy has a diameter of about 100 000 light-years and the Solar System is embedded in it about half way between the centre and periphery. From our vantage point, this huge disc of stars, gas and dust appears as a circular strip winding around the sky, familiar as the Milky Way in the night sky.

Denser portions of the interstellar medium, the mixture of gas and dust that pervades the Galaxy, are visible in orange and red, popping up against the background in this false-colour view. These concentrations of matter, often arranged in long, thread-like structures, are the sites where future generations of stars will form.

The tiny white spots that appear sprinkled over the filaments are denser clumps of gas and dust, embedding the seeds of stars that are slowly taking shape.

In contrast, the glowing blue and violet gas is set ablaze by the powerful light emitted by newborn stars in their vicinity. This signature of full-fledged stars completes the inventory of all stages in the process of stellar formation that are portrayed in this stunning panorama.

A set of individual images extracted from the video reveal several jewels nestled in the Galactic Plane, such as the Eagle Nebula, the Cat’s Paw Nebula, and the War and Peace Nebula.

These billowing clouds are home to clusters of young stars that are shining brightly and driving powerful winds, which are in turn carving cavities in the surrounding material, while at the same time the nebulas are ceaselessly witnessing the birth of new stars within them.

 The image of RCW 120 tells another tale of relentless star formation: a star at the centre, invisible at these infrared wavelengths, has blown a beautiful bubble around itself with the mighty pressure of the light it radiates.

The pressure is so strong that it has compressed the material at the edge of the bubble, causing it to collapse and triggering the birth of new stars.

More interesting sights are revealed near the Galactic Centre, where the density of stars is greater than elsewhere in the Milky Way. There, the clouds of gas and dust appear distributed along a giant, twisted ring, over 600 light-years wide, encompassing the supermassive black hole sitting at the Galaxy’s core.

Herschel obtained these unprecedented views by peering at the Milky Way in far infrared light to detect the glow of cosmic dust – a minor but crucial component of the interstellar mixture from which stars are born.

Related scientific paper by S. Molinari et al.
 

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RCW 120, How Far are You: I'm 4, 300 Light-Years Away

|| April 24: 2016 || The RCW 120 bubble seen by ESA’s Herschel space observatory. It lies about 4300 light-years away.

A star at the centre, not visible at these infrared wavelengths, has blown a beautiful bubble around itself with the mighty pressure of the light it radiates. The pressure is so strong that it has compressed the material at the edge of the bubble, causing it to collapse and triggering the birth of new stars.

The image is a composite of the wavelengths of 70 microns (blue), 160 microns (green) and 350 microns (red).

Acknowledgement: G. Li Causi, IAPS/INAF, ItalyReadmore

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Can You See the Galactic Centre, Herschel?

|| April 24: 2016 || Herschel’s view of the Galactic Centre: Released 22/04/2016 11:00 am: Copyright ESA/Herschel/PACS, SPIRE/Hi-GAL Project

The centre of our Galaxy, the Milky Way, about 25 000 light-years away, as seen seen by ESA’s Herschel space observatory.

Clouds of gas and dust appear distributed along a giant, twisted ring, over 600 light-years wide, which encompasses the supermassive black hole sitting at the Galaxy’s core.

The image is a composite of the wavelengths of 70 microns (blue), 160 microns (green) and 350 microns (red).

Acknowledgement: G. Li Causi, IAPS/INAF, Italy

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What Did You See, Herschel: It's the Spectacle of the Eagle

|| April 22, 2016 || The Eagle Nebula, also known as M 16, seen by ESA’s Herschel space observatory. The nebula lies about 6500 light-years away.

A group of young, bright stars, not visible at these infrared wavelengths, are located near the centre of the image. The powerful light emitted by these stars is setting the surrounding gas ablaze, causing it to shine; the stars also drive mighty winds that are carving the giant cavities in the cloud.

At the borders of these cavities, the interstellar mixture of gas and dust becomes denser, eventually collapsing and giving rise to a new generation of stars.

The image is a composite of the wavelengths of 70 microns (blue), 160 microns (green) and 350 microns (red).

Acknowledgement: G. Li Causi, IAPS/INAF, Italy
 

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Lone Planetary-Mass Object Found in Family of Stars

Whitney Clavin Writing

|| April 20, 2016 || In 2011, astronomers announced that our galaxy is likely teeming with free-floating planets. In fact, these lonely worlds, which sit quietly in the darkness of space without any companion planets or even a host sun, might outnumber stars in our Milky Way galaxy. The surprising discovery begged the question: Where did these objects come from? Are they planets that were ejected from solar systems, or are they actually light-weight stars called brown dwarfs that formed alone in space like stars?

A new study using data from NASA's Wide-field Infrared Survey Explorer, WISE, and the Two Micron All Sky Survey, or 2MASS, provides new clues in this mystery of galactic proportions. Scientists have identified a free-floating, planetary-mass object within a young star family, called the TW Hydrae association. The newfound object, termed WISEA J114724.10−204021.3, or just WISEA 1147 for short, is estimated to be between roughly five to 10 times the mass of Jupiter.

WISEA 1147 is one of the few free-floating worlds where astronomers can begin to point to its likely origins as a brown dwarf and not a planet. Because the object was found to be a member of the TW Hydrae family of very young stars, astronomers know that it is also very young -- only 10 million years old. And because planets require at least 10 million years to form, and probably longer to get themselves kicked out of a star system, WISEA 1147 is likely a brown dwarf. Brown dwarfs form like stars but lack the mass to fuse atoms at their cores and shine with starlight.

"With continued monitoring, it may be possible to trace the history of WISEA 1147 to confirm whether or not it formed in isolation," said Adam Schneider of the University of Toledo in Ohio, lead author of a new study accepted for publication in The Astrophysical Journal.

Of the billions of possible free-floating worlds thought to populate our galaxy, some may be very low-mass brown dwarfs, while others may in fact be bona fide planets, kicked out of nascent solar systems. At this point, the fraction of each population remains unknown. Tracing the origins of free-floating worlds, and determining whether they are planets or brown dwarfs, is a difficult task, precisely because they are so isolated.

"We are at the beginning of what will become a hot field – trying to determine the nature of the free-floating population and how many are planets versus brown dwarfs," said co-author Davy Kirkpatrick of NASA's Infrared Processing and Analysis Center, or IPAC, at the California Institute of Technology in Pasadena.

Astronomers found WISEA 1147 by sifting through images taken of the entire sky by WISE, in 2010, and 2MASS, about a decade earlier. They were looking for nearby, young brown dwarfs. One way to tell if something lies nearby is to check to see if it's moved significantly relative to other stars over time. The closer an object, the more it will appear to move against a backdrop of more distant stars. By analyzing data from both sky surveys taken about 10 years apart, the close objects jump out.

Finding low-mass objects and brown dwarfs is also well suited to WISE and 2MASS, both of which detect infrared light. Brown dwarfs aren't bright enough to be seen with visible-light telescopes, but their heat signatures light up when viewed in infrared images.

The brown dwarf WISEA 1147 was brilliantly "red" in the 2MASS images (where the color red had been assigned to longer infrared wavelengths), which means that it's dusty and young.

"The features on this one screamed out, 'I'm a young brown dwarf,'" said Schneider.

After more analysis, the astronomers realized that this object belongs to the TW Hydrae association, which is about 150 light-years from Earth and only about 10 million years old. That makes WISEA 1147, with a mass between about five and 10 times that of Jupiter, one of the youngest and lowest-mass brown dwarfs ever found.

Interestingly, a second, very similar low-mass member of the TW Hydrae association was announced just days later (2MASS 1119-11) by a separate group led by Kendra Kellogg of Western University in Ontario, Canada.

Another reason that astronomers want to study these isolated worlds is that they resemble planets but are easier to study. Planets around other stars, called exoplanets, are barely perceptible next to their brilliant stars. By studying objects like WISEA 1147, which has no host star, astronomers can learn more about their compositions and weather patterns.

"We can understand exoplanets better by studying young and glowing low-mass brown dwarfs," said Schneider. "Right now, we are in the exoplanet regime."

Other authors of the study include: James Windsor and Michael Cushing of the University of Toledo; and Ned Wright of UCLA, who was also the principal investigator of the WISE mission.

NASA's Jet Propulsion Laboratory in Pasadena, California, managed and operated WISE for NASA's Science Mission Directorate in Washington. The spacecraft was put into hibernation mode in 2011, after it scanned the entire sky twice, completing its main objectives. In September 2013, WISE was reactivated, renamed NEOWISE and assigned a new mission to assist NASA's efforts to identify potentially hazardous near-Earth objects.

The 2MASS mission was a joint effort between the California Institute of Technology, Pasadena; the University of Massachusetts, Amherst; and JPL. Caltech manages JPL for NASA.

WISE, NEOWISE and 2MASS data are archived at IPAC.

Whitney Clavin: Jet Propulsion Laboratory, Pasadena, California: 818-354-4673: whitney.clavin@jpl.nasa.gov

( Editor: Tony Greicius: NASA)

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A Milky Way 'Mixer' Amongst the Stars

April 07, 2016: A festive portrait of our Milky Way galaxy shows a mishmash of gas, charged particles and several types of dust. The composite image comes from the European Space Agency's Planck mission, in which NASA plays an important role. It is constructed from observations made at microwave and millimeter wavelengths of light, which are longer than what we see with our eyes.

Planck is largely a cosmology mission with the goal of learning more about our universe -- everything from its age and contents to how it was born and how it will evolve in the future. The space telescope spent more than four years detecting the oldest light in the universe, which traveled billions of years to reach us. But that ancient light comes to us mixed together with light of similar wavelengths generated closer to home, within our Milky Way and other nearby galaxies. Scientists painstakingly subtract the Milky Way's light to isolate the ancient signals -- but this nearby light benefits astronomers too.

As the map demonstrates, Planck can detect a frenzy of activity in our Milky Way. Astronomers use maps like these to better understand the composition, temperature, density and large-scale structure of the material between stars, in addition to patterns of star formation throughout our galaxy and the role of magnetic fields.

In this view, different colors represent various materials and types of radiation. Red shows dust that gives off a thermal glow, and makes up the most abundant of the dust features shown. Yellow shows carbon monoxide gas, which is concentrated along the plane of our Milky Way in the densest clouds of gas and dust that are churning out new stars.

Blue indicates a type of radiation called synchrotron, which occurs when fast-moving electrons, spit out of supernovas and other energetic phenomena, are captured in the galaxy’s magnetic field. The electrons spiral along the magnetic field, travelling near the speed of light.

The green shows a different kind of radiation known as free-free. This occurs when isolated electrons and protons careen past one another in a series of near collisions, slowing down but continuing on their own way (the name free-free comes from the fact that the particles start out alone and end up alone). The free-free signatures are associated with hot, ionized gas near massive stars.


( Editor: Tony Greicius: NASA)

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Trigger for Milky Way’s Youngest Supernova Identified

Molly Porter, Megan Watzke Writing

April 02, 2016: Scientists have used data from NASA’s Chandra X-ray Observatory and the NSF’s Jansky Very Large Array to determine the likely trigger for the most recent supernova in the Milky Way. They applied a new technique that could have implications for understanding other Type Ia supernovas, a class of stellar explosions that scientists use to determine the expansion rate of the Universe.

Astronomers had previously identified G1.9+0.3 as the remnant of the most recent supernova in our Galaxy. It is estimated to have occurred about 110 years ago in a dusty region of the Galaxy that blocked visible light from reaching Earth.

G1.9+0.3 belongs to the Type Ia category, an important class of supernovas exhibiting reliable patterns in their brightness that make them valuable tools for measuring the rate at which the universe is expanding.

“Astronomers use Type Ia supernovas as distance markers across the Universe, which helped us discover that its expansion was accelerating,” said Sayan Chakraborti, who led the study at Harvard University. “If there are any differences in how these supernovas explode and the amount of light they produce, that could have an impact on our understanding of this expansion.”

Most scientists agree that Type Ia supernovas occur when white dwarfs, the dense remnants of Sun-like stars that have run out of fuel, explode. However, there has been a debate over what triggers these white dwarf explosions. Two primary ideas are the accumulation of material onto a white dwarf from a companion star or the violent merger of two white dwarfs.

The new research with archival Chandra and VLA data examines how the expanding supernova remnant G1.0+0.3 interacts with the gas and dust surrounding the explosion. The resulting radio and X-ray emission provide clues as to the cause of the explosion. In particular, an increase in X-ray and radio brightness of the supernova remnant with time, according to theoretical work by Chakraborti’s team, is expected only if a white dwarf merger took place.

“We observed that the X-ray and radio brightness increased with time, so the data point strongly to a collision between two white dwarfs as being the trigger for the supernova explosion in G1.9+0.3,” said co-author Francesca Childs, also of Harvard.

The result implies that Type Ia supernovas are either all caused by white dwarf collisions, or are caused by a mixture of white dwarf collisions and the mechanism where the white dwarf pulls material from a companion star.

“It is important to identify the trigger mechanism for Type Ia supernovas because if there is more than one cause, then the contribution from each may change over time,” said Harvard’s Alicia Soderberg, another co-author on the study. This means astronomers might have to recalibrate some of the ways we use them as ‘standard candles’ in cosmology.”

The team also derived a new estimate for the age of the supernova remnant of about 110 years, younger than previous estimates of about 150 years.

More progress on understanding the trigger mechanism should come from studying Type Ia supernovas in nearby galaxies, using the increased sensitivity provided by a recent upgrade to the VLA.

A paper describing these results appeared in the March 1st, 2016 issue of The Astrophysical Journal and is available online. NASA's Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program for NASA's Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, controls Chandra's science and flight operations.

Read More from NASA's Chandra X-ray Observatory.

For more Chandra images, multimedia and related materials, visit: http://www.nasa.gov/chandra

Molly Porter: Marshall Space Flight Center, Huntsville, Ala. 256-544-0034: molly.a.porter@nasa.gov

Megan Watzke: Chandra X-ray Center, Cambridge, Mass. 617-496-7998: mwatzke@cfa.harvard.edu
( Editor: Lee Mohon:NASA)
 

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And What are You Going to Do With the Ribbon, Milky Way: I Think I'm Going to Put It Around My Star-Bloomed Hair

March 29, 2016: Star formation is taking place all around us. The Milky Way is laced with clouds of dust and gas that could become the nursery of the next generation of stars. Thanks to ESA’s Herschel space observatory, we can now look inside these clouds and see what is truly going on.

It may seem ironic but when searching for sites of future star formation, astronomers look for the coldest spots in the Milky Way. This is because before the stars ignite the gas that will form their bulk must collapse together. To do that, it has to be cold and sluggish, so that it cannot resist gravity.

As well as gas, there is also dust. This too is extremely cold, perhaps just 10–20 degrees above absolute zero. To optical telescopes it appears completely dark, but the dust reveals itselfat far-infrared wavelengths.

One of the surprises is that the coldest parts of the cloud form filaments that stretch across the warmer parts of the cloud. This image shows a cold cloud filament, known to astronomers as G82.65-2.00. The blue filament is the coldest part of the cloud and contains 800 times as much mass as the Sun. The dust in this filament has a temperature of –259ºC. At this low temperature, if the filament contains enough mass it is likely that this section will collapse into stars.

This image is colour-coded so that the longest infrared wavelength, corresponding to the coldest region, is shown in blue, and the shortest wavelength, corresponding to slightly warmer dust, is shown in red.

The field of view on display here is a little more than two times the width of the full Moon. It is one of 116 regions of space observed by Herschel as part of the Galactic Cold Cores project. Each field was chosen because ESA’s cosmic microwave background mapper, Planck, showed that these regions of the galaxy possessed extremely cold dust.

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Milky Way Galaxy's Own Centrica: the Supermassive Black Hole Sagittarius A

March 21, 2016: Three orbiting X-ray space telescopes have detected an increased rate of X-ray flares from the usually quiet giant black hole at the center of our Milky Way galaxy after new long-term monitoring. Scientists are trying to learn whether this is normal behavior that was unnoticed due to limited monitoring, or these flares are triggered by the recent close passage of a mysterious, dusty object.

By combining information from long monitoring campaigns by NASA’s Chandra X-ray Observatory and ESA’s XMM-Newton, with observations by the Swift satellite, astronomers were able to carefully trace the activity of the Milky Way’s supermassive black hole over the last 15 years. The supermassive black hole, a.k.a. Sagittarius A*, weighs in at slightly more than 4 million times the mass of the Sun. X-rays are produced by hot gas flowing toward the black hole.

The new study reveals that Sagittarius A* (Sgr A* for short) has been producing one bright X-ray flare about every ten days. However, within the past year, there has been a ten-fold increase in the rate of bright flares from Sgr A*, at about one every day. This increase happened soon after the close approach to Sgr A* by a mysterious object called G2.

“For several years, we’ve been tracking the X-ray emission from Sgr A*. This includes also the close passage of this dusty object” said Gabriele Ponti of the Max Planck Institute for Extraterrestrial Physics in Germany. “A year or so ago, we thought it had absolutely no effect on Sgr A*, but our new data raise the possibility that that might not be the case."

Originally, astronomers thought G2 was an extended cloud of gas and dust. However, after passing close to Sgr A* in late 2013, its appearance did not change much, apart from being slightly stretched by the gravity of the black hole. This led to new theories that G2 was not simply a gas cloud, but instead a star swathed in an extended dusty cocoon.

“There isn’t universal agreement on what G2 is,” said Mark Morris of the University of California at Los Angeles. “However, the fact that Sgr A* became more active not long after G2 passed by suggests that the matter coming off of G2 might have caused an increase in the black hole’s feeding rate.”

While the timing of G2’s passage with the surge in X-rays from Sgr A* is intriguing astronomers see other black holes that seem to behave like Sgr A*. Therefore, it’s possible this increased chatter from Sgr A* may be a common trait among black holes and unrelated to G2. For example, the increased X-ray activity could be due to a change in the strength of winds from nearby massive stars that are feeding material to the black hole.

“It’s too soon to say for sure, but we will be keeping X-ray eyes on Sgr A* in the coming months,” said co-author Barbara De Marco, also of Max Planck. “Hopefully, new observations will tell us whether G2 is responsible for the changed behavior or if the new flaring is just part of how the black hole behaves.”

The analysis included 150 Chandra and XMM-Newton observations pointed at the center of the Milky Way over the last 15 years, extending from September 1999 to November 2014. An increase in the rate and brightness of bright flares from Sgr A* occurred after mid-2014, several months after the closest approach of G2 to the huge black hole.

If the G2 explanation is correct, the spike in bright X-ray flares would be the first sign of excess material falling onto the black hole because of the cloud’s close passage. Some gas would likely have been stripped off the cloud, and captured by the gravity of Sgr A*. It then could have started interacting with hot material flowing towards the black hole, funneling more gas toward the black hole that could later be consumed by Sgr A*.

A paper on these findings has been accepted by the Monthly Notices of the Royal Astronomical Society. A preprint is available online. NASA's Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program for NASA's Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, controls Chandra's science and flight operations.

For more Chandra images, multimedia and related materials, visit: http://www.nasa.gov/chandrab

( Editor: Lee Mohon:NASA)

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Hubble Watches Minkowski's Hen's Icy Blue Wings

In this cosmic snapshot, the spectacularly symmetrical wings of Hen 2-437 show up in a magnificent icy blue hue. Hen 2-437 is a planetary nebula, one of around 3,000 such objects known to reside within the Milky Way.

Located within the faint northern constellation of Vulpecula (The Fox), Hen 2-437 was first identified in 1946 by Rudolph Minkowski, who later also discovered the famous and equally beautiful M2-9 (otherwise known as the Twin Jet Nebula). Hen 2-437 was added to a catalog of planetary nebula over two decades later by astronomer and NASA astronaut Karl Gordon Henize.

Planetary nebulae such as Hen 2-437 form when an aging low-mass star — such as the sun — reaches the final stages of life. The star swells to become a red giant, before casting off its gaseous outer layers into space. The star itself then slowly shrinks to form a white dwarf, while the expelled gas is slowly compressed and pushed outwards by stellar winds. As shown by its remarkably beautiful appearance, Hen 2-437 is a bipolar nebula — the material ejected by the dying star has streamed out into space to create the two icy blue lobes pictured here.

Image credit: ESA (European Space Agency)/Hubble & NASA, Acknowledgement: Judy Schmidt

Text credit: ESA

( Editor: Rob Garner: NASA)

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Twinkle Twinkle Diamond Stars How I Wonder Deep and Far

Hubble Unveils a Tapestry of Dazzling Diamond-like Stars

Resembling an opulent diamond tapestry, this image from NASA’s Hubble Space Telescope shows a glittering star cluster that contains a collection of some of the brightest stars seen in our Milky Way galaxy. Called Trumpler 14, it is located 8,000 light-years away in the Carina Nebula, a huge star-formation region. Because the cluster is only 500,000 years old, it has one of the highest concentrations of massive, luminous stars in the entire Milky Way.

The small, dark knot left of center is a nodule of gas laced with dust, and seen in silhouette.

Resembling an opulent diamond tapestry, this image from NASA’s Hubble Space Telescope shows a glittering star cluster that contains a collection of some of the brightest stars seen in our Milky Way galaxy.
Credits: NASA, ESA, and J. Maíz Apellániz (Institute of Astrophysics of Andalusia, Spain), Acknowledgment: N. Smith (University of Arizona)

These blue-white stars are burning their hydrogen fuel so ferociously they will explode as supernovae in just a few million years. The combination of outflowing stellar “winds” and, ultimately, supernova blast waves will carve out cavities in nearby clouds of gas and dust. These fireworks will kick-start the beginning of a new generation of stars in an ongoing cycle of star birth and death.

This composite image of Trumpler 14 was made with data taken in 2005-2006 with Hubble's Advanced Camera for Surveys. Blue, visible and infrared broadband filters combine with filters that isolate hydrogen and nitrogen emission from the glowing gas surrounding the open cluster.

For images and more information about Hubble, visit:

http://www.nasa.gov/hubble
http://hubblesite.org/news/2016/03
 
For additional information, contact:

Ray Villard
Space Telescope Science Institute, Baltimore, Maryland
410-338-4514
villard@stsci.edu


: Editor: Ashley Morrow: NASA

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Runaway Stars Leave Infrared Waves in Space

Astronomers are finding dozens of the fastest stars in our galaxy with the help of images from NASA's Spitzer Space Telescope and Wide-field Infrared Survey Explorer, or WISE.

When some speedy, massive stars plow through space, they can cause material to stack up in front of them in the same way that water piles up ahead of a ship. Called bow shocks, these dramatic, arc-shaped features in space are leading researchers to uncover massive, so-called runaway stars.
"Some stars get the boot when their companion star explodes in a supernova, and others can get kicked out of crowded star clusters," said astronomer William Chick from the University of Wyoming in Laramie, who presented his team's new results at the American Astronomical Society meeting in Kissimmee, Florida. "The gravitational boost increases a star's speed relative to other stars."

Our own sun is strolling through our Milky Way galaxy at a moderate pace. It is not clear whether our sun creates a bow shock. By comparison, a massive star with a stunning bow shock, called Zeta Ophiuchi (or Zeta Oph), is traveling around the galaxy faster than our sun, at 54,000 mph (24 kilometers per second) relative to its surroundings. Zeta Oph's giant bow shock can be seen in this image from the WISE mission:

http://www.nasa.gov/mission_pages/WISE/multimedia/gallery/pia13455.html

Both the speed of stars moving through space and their mass contribute to the size and shapes of bow shocks. The more massive a star, the more material it sheds in high-speed winds. Zeta Oph, which is about 20 times as massive as our sun, has supersonic winds that slam into the material in front of it.

The result is a pile-up of material that glows. The arc-shaped material heats up and shines with infrared light. That infrared light is assigned the color red in the many pictures of bow shocks captured by Spitzer and WISE.

Chick and his team turned to archival infrared data from Spitzer and WISE to identify new bow shocks, including more distant ones that are harder to find. Their initial search turned up more than 200 images of fuzzy red arcs. They then used the Wyoming Infrared Observatory, near Laramie, to follow up on 80 of these candidates and identify the sources behind the suspected bow shocks. Most turned out to be massive stars.

The findings suggest that many of the bow shocks are the result of speedy runaways that were given a gravitational kick by other stars. However, in a few cases, the arc-shaped features could turn out to be something else, such as dust from stars and birth clouds of newborn stars. The team plans more observations to confirm the presence of bow shocks.

"We are using the bow shocks to find massive and/or runaway stars," said astronomer Henry "Chip" Kobulnicky, also from the University of Wyoming. "The bow shocks are new laboratories for studying massive stars and answering questions about the fate and evolution of these stars."

Another group of researchers, led by Cintia Peri of the Argentine Institute of Radio Astronomy, is also using Spitzer and WISE data to find new bow shocks in space. Only instead of searching for the arcs at the onset, they start by hunting down known speedy stars, and then they scan them for bow shocks.

"WISE and Spitzer have given us the best images of bow shocks so far," said Peri. "In many cases, bow shocks that looked very diffuse before, can now be resolved, and, moreover, we can see some new details of the structures."

Some of the first bow shocks from runaway stars were identified in the 1980s by David Van Buren of NASA's Jet Propulsion Laboratory in Pasadena, California. He and his colleagues found them using infrared data from the Infrared Astronomical Satellite (IRAS), a predecessor to WISE that scanned the whole infrared sky in 1983.

Kobulnicky and Chick belong to a larger team of researchers and students studying bow shocks and massive stars, including Matt Povich from the California State Polytechnic University, Pomona. The National Science Foundation funds their research.

Images from Spitzer, WISE and IRAS are archived at the NASA Infrared Science Archive housed at the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena. Caltech manages JPL for NASA.

More information about Spitzer is online at:

http://www.nasa.gov/spitzer

http://spitzer.caltech.edu

More information about WISE is at:

http://www.nasa.gov/wise

Whitney Clavin
Jet Propulsion Laboratory, Pasadena, California
818-354-4673
whitney.clavin@jpl.nasa.gov
( Editor: Martin Perez: NASA)

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The Magnetic Field Along the Galactic Plane of the Milky Way

While the pastel tones and fine texture of this image may bring to mind brush strokes on an artist’s canvas, they are in fact a visualisation of data from ESA’s Planck satellite. The image portrays the interaction between interstellar dust in the Milky Way and the structure of our Galaxy’s magnetic field.
Between 2009 and 2013, Planck scanned the sky to detect the most ancient light in the history of the Universe – the cosmic microwave background. It also detected significant foreground emission from diffuse material in our Galaxy which, although a nuisance for cosmological studies, is extremely important for studying the birth of stars and other phenomena in the Milky Way.

Among the foreground sources at the wavelengths probed by Planck is cosmic dust, a minor but crucial component of the interstellar medium that pervades the Galaxy. Mainly gas, it is the raw material for stars to form.

Interstellar clouds of gas and dust are also threaded by the Galaxy’s magnetic field, and dust grains tend to align their longest axis at right angles to the direction of the field. As a result, the light emitted by dust grains is partly ‘polarised’ – it vibrates in a preferred direction – and, as such, could be caught by the polarisation-sensitive detectors on Planck.

Scientists in the Planck collaboration are using the polarised emission of interstellar dust to reconstruct the Galaxy’s magnetic field and study its role in the build-up of structure in the Milky Way, leading to star formation.

In this image, the colour scale represents the total intensity of dust emission, revealing the structure of interstellar clouds in the Milky Way. The texture is based on measurements of the direction of the polarised light emitted by the dust, which in turn indicates the orientation of the magnetic field.

This image shows the intricate link between the magnetic field and the structure of the interstellar medium along the plane of the Milky Way. In particular, the arrangement of the magnetic field is more ordered along the Galactic plane, where it follows the spiral structure of the Milky Way. Small clouds are seen just above and below the plane, where the magnetic field structure becomes less regular.

From these and other similar observations, Planck scientists found that filamentary interstellar clouds are preferentially aligned with the direction of the ambient magnetic field, highlighting the strong role played by magnetism in galaxy evolution.

The emission from dust is computed from a combination of Planck observations at 353, 545 and 857 GHz, whereas the direction of the magnetic field is based on Planck polarisation data at 353 GHz.

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An Akari-view of the Cygnus Region in the Milky Way

The constellation of Cygnus is one of the most recognisable in the northern hemisphere. During the summer months, the stars of its long neck stretch along the Milky Way and its wings sweep from side to side.

Switch to the invisible wavelengths of the far-infrared and the Milky Way’s river of stars disappears to reveal tendrils of cold dust. Shown here, in this image from Japan’s Akari space observatory, are the central regions of Cygnus, and it can be seen that the Milky Way displays a rich stock of dust.

This dust is part of the interstellar medium, which also contains gas. These infrared images reveal the detailed distribution of the interstellar medium, highlighting areas where bright, new stars are about to emerge in the Milky Way.

Far-infrared light is the key wavelength range for investigating stars and planet formation. When the interstellar medium gathers together under the attraction of its own gravity, it forms a giant molecular cloud. These can be hundreds of light-years across. Denser parts, just a few tenths of a light-year across, are known as molecular cloud cores. These are where stars and planets form.

Akari images, such as this one, are the only images in which scientists can closely examine the entire giant molecular cloud with the resolution of a molecular cloud core.

This false-colour image, spanning 20x15°, is constructed from three far-infrared bands: blue represents 65 micrometres, green shows 90 micrometres and red codes the 140 micrometre wavelength. The image is part of Akari’s recently released all-sky survey.

The mission observed more than 99% of the entire sky over a period of 16 months. The all-sky images have a resolution of 1–1.5 arcminutes, in four wavelengths: 65, 90, 140 and 160 micrometres.

Akari was a Japan Aerospace Exploration Agency (JAXA) project with ESA’s participation.

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