Posted on by Tammy Plotner

Cooking Up Stars In Cygnus X

A bubbling cauldron of star birth is highlighted in this new image from NASA's Spitzer Space Telescope. Image credit: NASA/JPL-Caltech/Harvard-Smithsonian CfA

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Thanks to the incredible infra-red imagery of NASA’s Spitzer Space Telescope, we’re able to take a look into a tortured region of star formation. Infrared light in this image has been color-coded according to wavelength. Light of 3.6 microns is blue, 4.5-micron light is blue-green, 8.0-micron light is green, and 24-micron light is red. The data was taken before the Spitzer mission ran out of its coolant in 2009, and began its “warm” mission. This image reveals one of the most active and tumultuous areas of the Milky Way – Cygnus X. Located some 4,500 light years away, the violent-appearing dust cloud holds thousands of massive stars and even more of moderate size. It is literally “star soup”…

“Spitzer captured the range of activities happening in this violent cloud of stellar birth,” said Joseph Hora of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass., who presented the results today at the 219th meeting of the American Astronomical Society in Austin, Texas. “We see bubbles carved out by massive stars, pillars of new stars, dark filaments lined with stellar embryos and more.”

According to popular theory, stars are created in regions similar to Cygnus X. As their lives progress, they drift away from each other and it is surmised the Sun once belonged to a stellar association formed in a slightly less extreme environment. In regions like Cygnus X, the dust clouds are characterized with deformations caused by stellar winds and high radiation. The massive stars literally shred the clouds that birth them. This action can stop other stars from forming… and also cause the rise of others.

“One of the questions we want to answer is how such a violent process can lead to both the death and birth of new stars,” said Sean Carey, a team member from NASA’s Spitzer Science Center at the California Institute of Technology, Pasadena, Calif. “We still don’t know exactly how stars form in such disruptive environments.”

Thanks to Spitzer’s infra-red data, scientists are now able to paint a clearer picture of what happens in dusty complexes. It allows astronomers to peer behind the veil where embryonic stars were once hidden – and highlights areas like pillars where forming stars pop out inside their cavities. Another revelation is dark filaments of dust, where embedded stars make their home. It is visions like this that has scientists asking questions… Questions such as how filaments and pillars could be related.

“We have evidence that the massive stars are triggering the birth of new ones in the dark filaments, in addition to the pillars, but we still have more work to do,” said Hora.

Original Story Source: NASA Spitzer News Release.

Posted on by Jason Major

NASA’s Airborne Observatory Targets Newborn Stars

Infrared image of the W3A star cluster in Perseus. (SOFIA image -- NASA / DLR / USRA / DSI / FORCAST team Spitzer image -- NASA / Caltech - JPL.)

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(DING!) “The captain has turned off the safety lights – you are now free to explore the infrared Universe.”

Mounted inside the fuselage of a Boeing 747SP aircraft, NASA’s Stratospheric Observatory for Infrared Astronomy, or SOFIA, is capable of searching the sky in infrared light with a sensitivity impossible from ground-based instruments. Cruising at 39,000 to 45,000 feet, its 100-inch telescope operates above 99% of the atmospheric water vapor that would otherwise interfere with such observations, and thus is able to pierce through vast interstellar clouds of gas and dust to find what lies within.

Its latest discovery has uncovered a cluster of newborn stars within a giant cloud of gas and dust 6,400 light-years from Earth.

The massive stars are still enshrouded in the gas cloud from which they formed, a region located in the direction of Perseus called W3. The Faint Object Infrared Camera for the SOFIA Telescope (FORCAST) instrument was able to peer through the cloud and locate up to 15 massive young stars clustered together in a compact region, designated W3A.

SOFIA's 747SP on the ground at NASA's Dryden Flight Research Center on Edwards Air Force Base, CA. (NASA/Tony Landis)

W3A’s stars are seen in various stages of formation, and their effects on nearby clouds of gas and dust are evident in the FORCAST inset image above. A dark bubble, which the arrow is pointing to, is a hole created by emissions from the largest of the young stars, and the greenish coloration surrounding it designates regions where the dust and large molecules have been destroyed by powerful radiation.

Without SOFIA’s infrared imaging capabilities newborn stars like those seen in W3A would be much harder to observe, since their visible and ultraviolet light typically can’t escape the cool, opaque dust clouds where they are located.

The radiation emitted by these massive young stars may eventually spur more star formation within the surrounding clouds. Our own Sun likely formed in this same way, 5 billion years ago, within a cluster of its own stellar siblings which have all long since drifted apart. By observing clusters like W3A astronomers hope to better understand the process of star birth and ultimately the formation of our own solar system.

Read more on the SOFIA news release here.

The observation team’s research principal investigator is Terry Herter of Cornell University. The data were analyzed and interpreted by the FORCAST team with Francisco Salgado and Alexander Tielens of the Leiden Observatory in the Netherlands plus SOFIA staff scientist James De Buizer. These papers have been submitted for publication in The Astrophysical Journal.

Posted on by Tammy Plotner

We Are Stardust… We Are Cold Then

This new image shows the Large Magellanic Cloud galaxy in infrared light as seen by the Herschel Space Observatory, a European Space Agency-led mission with important NASA contributions, and NASA's Spitzer Space Telescope. Image credit: ESA/NASA/JPL-Caltech/STScI

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When we think of stars, we might think of their building blocks as white hot… But that’s not particularly the case.The very “stuff” that creates a sun is cold dust and in this combined image produced by the Herschel Space Observatory, a European Space Agency-led mission with important NASA contributions; and NASA’s Spitzer Space Telescope, we’re taking an even more incredible look into the environment which forms stars. This new image peers into the dusty arena of both the Large and Small Magellanic Clouds – just two of our galactic neighbors.

Through the infra-red eyes of the Herschel-Spitzer observation, the Large Magellanic Cloud would almost appear to look like a gigantic fireball. Here light-years long bands of dust permeate the galaxy with blazing fields of star formation seen in the center, center-left and top right (the brightest center-left region is called 30 Doradus, or the Tarantula Nebula. The Small Magellanic Cloud is much more disturbed looking. Here we see a huge filament of dust to the left – known as the galaxy’s “wing” – and, to the right, a deep bar of star formation.

This new image shows the Small Magellanic Cloud galaxy in infrared light from the Herschel Space Observatory a European Space Agency-led mission with important NASA contributions, and NASA's Spitzer Space Telescope. Image credit: ESA/NASA/JPL-Caltech/STScI

What makes these images very unique is that they are indicators of temperature within the Magellanic Clouds. The cool, red areas are where star formation has ceased or is at its earliest stages. Warm areas are indicative of new stars blooming to life and heating the dust around them. “Coolest areas and objects appear in red, corresponding to infrared light taken up by Herschel’s Spectral and Photometric Imaging Receiver at 250 microns, or millionths of a meter. Herschel’s Photodetector Array Camera and Spectrometer fills out the mid-temperature bands, shown in green, at 100 and 160 microns.” says the research team. “The warmest spots appear in blue, courtesy of 24- and 70-micron data from Spitzer.”

Both the LMC and SMC are the two largest satellite galaxies of the Milky Way and are cataloged as dwarf galaxies. While they are large in their own right, this pair contains fewer essential star-forming elements such as hydrogen and helium – slowing the rate of star growth. Although star formation is generally considered to have reached its apex some 10 billion years ago, some galaxies were left with less basic materials than others.

“Studying these galaxies offers us the best opportunity to study star formation outside of the Milky Way,” said Margaret Meixner, an astronomer at the Space Telescope Science Institute, Baltimore, Md., and principal investigator for the mapping project. “Star formation affects the evolution of galaxies, so we hope understanding the story of these stars will answer questions about galactic life cycles.”

Original Story Source: NASA/Herschel News.

Posted on by Tammy Plotner

Dodging Black Hole Bullets

This 327-MHz radio view of the center of our galaxy highlights the position of the black hole system H1743-322, as well as other features. (Credit: J. Miller-Jones, ICRAR-Curtin Univ.; C. Brogan, NRAO)

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In mid-2009 a binary star system cataloged as H H1743–322 shot off something very unusual. Poised about 28,000 light years distant in the direction of the constellation of Scorpius, this rather ordinary system made up of a normal star and unknown mass black hole was busy exchanging mass. The pair orbits in mere days with a stream of material flowing continuously between them. This gas causes a flat accretion disk measuring millions of miles across to form and it is centered on the black hole. As the matter twirls toward the center, it becomes compressed and heats to tens of millions of degrees, spitting out X-rays… and bullets.

Utilizing data from NASA’s Rossi X-ray Timing Explorer (RXTE) satellite and the National Science Foundation’s (NSF) Very Long Baseline Array (VLBA) radio telescope, an international team of astronomers were able to confirm the moment a black hole located within our galaxy fired a super speedy clump of gas into surrounding space. Blasting forth at about one-quarter the speed of light, these “bullets” of ionized gas are hypothesized to have originated from an area just outside the black hole’s event horizon.

“Like a referee at a sports game, we essentially rewound the footage on the bullets’ progress, pinpointing when they were launched,” said Gregory Sivakoff of the University of Alberta in Canada. He presented the findings today at the American Astronomical Society meeting in Austin, Texas. “With the unique capabilities of RXTE and the VLBA, we can associate their ejection with changes that likely signaled the start of the process.”

As we have learned, some of the matter headed toward the center of a black hole can be ejected from the accretion disk as opposing twin jets. For the most part, these jets are a constant stream of particles, but can sometimes form into strong “outflows” which get spit out – rapid fire – as gaseous blobs. In early June 2009, H1743–322 did just that… and astronomers were on hand observing with RXTE, the VLBA, the Very Large Array near Socorro, N.M., and the Australia Telescope Compact Array (ATCA) near Narrabri in New South Wales. During this time they were able to confirm the happenings through X-ray and radio data. From May 28 to June 2, things were nominal “though RXTE data show that cyclic X-ray variations, known as quasi-periodic oscillations or QPOs, gradually increased in frequency over the same period” and by June 4th, ATCA verified that activity had pretty much sloughed off. By June 5th, even the QPOs were gone.

Then it happened…

On the same day that everything went totally quiet, H1743–322 fired off a bullet! Radio emissions jumped and a highly accurate and detailed VLBA image disclosed a energetic missile of gas blasting forth along a jet trajectory. The very next day a second bullet took out in the opposite direction. But this wasn’t the curious part of the event… It was the timing. Up to this point, researchers speculated that a radio outburst accompanied the firing of the gas bullet, but VLBA information showed they were launched around 48 hours in advance of the major radio flare. This information will be published in the Monthly Notices of the Royal Astronomical Society.

Radio imaging by the Very Long Baseline Array (top row), combined with simultaneous X-ray observations by NASA's RXTE (middle), captured the transient ejection of massive gas "bullets" by the black hole binary H1743-322 during its 2009 outburst. By tracking the motion of these bullets with the VLBA, astronomers were able to link the ejection event to the disappearance of X-ray signals seen in RXTE data. These signals, called quasi-periodic oscillations (QPOs), vanished two days earlier than the onset of the radio flare that astronomers previously had assumed signaled the ejection. (Credit: NRAO and NASA's Goddard Space Flight Center)

“This research provides new clues about the conditions needed to initiate a jet and can guide our thinking about how it happens,” said Chris Done, an astrophysicist at the University of Durham, England, who was not involved in the study.

These are just mini-ammo compared to what happens in the center of an active galaxy. They don’t just fire bullets – they blast off cannons. A massive black hole weighing in a millions to billions of times the mass of the Sun can shoot off its load across millions of light years!

“Black hole jets in binary star systems act as fast-forwarded versions of their galactic-scale cousins, giving us insights into how they work and how their enormous energy output can influence the growth of galaxies and clusters of galaxies,” said lead researcher James Miller-Jones at the International Center for Radio Astronomy Research at Curtin University in Perth, Australia.

Original Story Source: NASA News Feature.

Posted on by Ray Sanders

Wandering Stars Shed Light on Milky Way’s Past

Measurements of the metal content of stars in the disk of our galaxy. The bottom panel shows the decrease in metal content as the distance from the galactic center increases for stars near the plane of the Milky Way disk. In contrast, the metal content for stars far above the plane, shown in the upper panel, is nearly constant at all distances from the center of the Galaxy. Image Credit: Judy Cheng and Connie Rockosi (UCSC) and the 2MASS Survey.

[/caption]Like a worldly backpacker, many stars in the Milky Way Galaxy have made interesting journeys, and have interesting stories to tell about their past. For over a decade, the Sloan Digital Sky Survey (SDSS) has been mapping stars in our Galaxy.

This week at the American Astronomical Society meeting in Austin, Texas, astronomers from University of California – Santa Cruz presented new evidence that claims to answer many questions about stars located in the disk of our galaxy. The team’s results are based on data from the Sloan Extension for Galactic Understanding and Exploration 2 (SEGUE-2).

The SEGUE-2 data is comprised of the motions and chemical compositions of over 118,000 stars, most of which are in the disk of our galaxy, but a few stars in the survey take the “scenic” route in their orbit.

“Some disk stars have orbits that take them far above and below the plane of the Milky Way,” said Connie Rockosi (University of California – Santa Cruz), “We want to understand what kinds of stars those are, where they came from, and how they got there.”

Aside from the orbital paths of these “wandering” stars being different from most other Milky Way stars, their chemical composition also makes them unique. A team led by Judy Cheng (University of California – Santa Cruz) studied the metallicity of stars at different locations in the galaxy. By studying the metallicity, Cheng and her team were able to examine how the disk of the Milky Way disk grew over time. Cheng’s study also showed that stars closer to the center of the galaxy have higher metallicity than those farther from the galactic center. “That tells us that the outer disk of our Galaxy has formed fewer generations of stars than the inner disk, meaning that the Milky Way disk grew from the inside out,” added Cheng.

When Cheng studied the “wandering” stars, she found their metallicity doesn’t follow the same trend – no matter where she looked in the target area of the Galaxy, stars had low metal content. “The fact that the metal content of those stars is the same everywhere is a new piece of evidence that can help us figure out how they got to be so far away from the plane,” Rockosi mentioned.

What the team has yet to determine is if the stars formed with their “wandering” orbits, or if something in the past caused them to migrate to their unique paths. “If these stars were born with these orbits, they were born at the same rate all over the galaxy,” Cheng said. “If they were born with regular orbits, then whatever happened to them must have been very efficient at mixing them up and erasing any patterns in the metal content, such as the inside-out trend we see in the plane.”

Some possible reasons for this mixing include past mergers of our Galaxy and others, or possibly spiral arms sweeping through the disk. Cheng’s observations will help determine what causes stars to wander far from their birthplace. Other galaxies have shown stars in their disks as well, so solving the puzzle presented by these stars will help researchers better understand how spiral galaxies like the Milky Way form.

If you’d like to read Cheng and Rockosi’s paper “Metallicity Gradients In The Milky Way Disk As Observed By The SEGUE Survey”, you can download a copy at: http://www.ucolick.org/~jyc/gradient/cheng_apj_fullres.pdf

Source: UC Santa Cruz press release

Posted on by Tammy Plotner

Suburu Telescope Captures Hidden Planets In Stellar Dust Ring

Near-infrared (1.6 micron) image of the debris ring around the star HR 4796 A. An astronomical unit (AU) is a unit of length that corresponds to the average distance between the Earth and Sun, almost 92 million miles (over 149 million km). The ring consists of dust grains in a wide orbit (roughly twice the size of Pluto's orbit) around the central star. Its edge is so precisely revealed that the researchers could confirm a previously suspected offset between the ring's center and the star's location. This "wobble" in the dust's orbit is most likely caused by the unbalancing action of – so far undetected – massive planets likely to be orbiting within the ring. Furthermore, the image of the ring appears to be smudged out at its tips and reveals the presence of finer dust extending out beyond the main body of the ring. Credit: Suburu

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No. It’s not a new atomic image – it’s a very unusual look at a star which could help further our understanding of stellar disk structure and planetary formation. As part of the SEEDS (Strategic Exploration of Exoplanets and Disks with Subaru Telescope/HiCIAO) project, this image of star HR 4796 was taken with Subaru’s planet-finder camera, HiCIAO (High Contrast Instrument for the Subaru Next Generation Adaptive Optics). At only about 8-10 million years old, the feature of this stellar image is only about 240 light years away from Earth, yet fully displays its ring of dust grains which reach out about twice the distance as Pluto’s orbit from the central star. This image produced by an international group led by Motohide Tamura of NAOJ (National Astronomical Observatory of Japan) is so wonderfully detailed that an offset between its center and the star’s position can be measured. While the offset was predicted by data from the Hubble and another research group, this new photographic evidence not only confirms its presence – but shows it to be larger than expected.

With new data to work from, researchers began to wonder exactly what could have caused the dust torus to run off its axis. The easiest explanation would be gravitational force – where one or more planets located inside the gap within the ring could possibly be affecting the disk. This type of action could account for an “unbalancing” which could act in a predictable manner. Current computer modeling has shown these types of “gravitational tides” can mold a dust torus in unusual ways and they cite similar data gathered from observations of bright star, Formalhaut. Since no planet candidates have yet been directly observed around HR 4796, chances are any planets present are simply too small and dim to be spotted. However, thanks to the new Suburu image, researchers feel confident their presence could be the source of the circumstellar dust ring wobble.

With image accuracy as pinpoint as the Hubble Space Telescope, the Suburu near-infrared depiction allows for extremely accurate measurements by employing its adaptive optics system. This type of advanced astrophotography also allows for angular differential imaging – by-passing the glare of the central star and enhancing the faint signature of the dust ring. Such techniques are able to establish heightened information about the relationship of the circumstellar disk and gelling planets… a process which may begin from the “left-overs” of initial star formation. As surmised, this material could either be picked up by newly formed planets or be pushed out the system via stellar winds. Either way, it is a process which eliminates the majority of the dust within a few tens of millions of years. However, there are a few stars which continue to hold on to a “secondary disk” – a collection of dust which could be attributed to the collision of planetesimals. In the case of HR 4796, this is a likely scenario and studying it may provide a better understanding of how planets could form in this alternate debris disk.

Original Story Source: Suburu Telescope News Release. For Further Reading: Direct Images of Disks Unravel Mystery of Planet Formation.

Posted on by Ray Sanders

A New Look at the Milky Way’s Central Bar

The BRAVA fields are shown in this image montage. For reference, the center of the Milky Way is at coordinates L= 0, B=0. The regions observed are marked with colored circles. This montage includes the southern Milky Way all the way to the horizon, as seen from CTIO. The telescope in silhouette is the CTIO Blanco 4-m. (Just peaking over the horizon on the left is the Large Magellanic Cloud, the nearest external galaxy to our own.) Image Credit: D. Talent, K. Don, P. Marenfeld & NOAO/AURA/NSF and the BRAVA Project

[/caption]You may have heard about the restaurant at the end of the Universe, but have you heard of the bar in the middle of the Milky Way?

Nearly 80 years ago, astronomers determined that our home, the Milky Way Galaxy, is a large spiral galaxy. Despite being stuck inside and not being able to see what the entire the structure looks like — as we can with the Pinwheel Galaxy, or our nearest neighbor, the Andromeda Galaxy — researchers have suspected our galaxy is actually a “barred” spiral galaxy. Barred spiral galaxies feature an elongated stellar structure , or bar, in the middle which in our case is hidden by dust and gas. There are many galaxies in the Universe that are barred spirals, and yet, there are numerous galaxies which do not feature a central bar.

How do these central bars form, and why are they only present in some, but not all spiral galaxies?

A research team led by Dr. R. Michael Rich (UCLA), dubbed BRAVA (Bulge Radial Velocity Assay), measured the velocity of many old, red stars near the center of our galaxy. By studying the spectra (combined light) of the M class giant stars, the team was able to calculate the velocity of each star along our line of sight. During a four-year time span, the spectra for nearly 10,000 stars was acquired with the CTIO Blanco 4-meter telescope located in Chile’s Atacama desert.

Analyzing the velocities of stars in their study, the team was able to confirm that the Milky Way’s central bulge does contain a massive bar, with one end nearly pointed right at our solar system. One other discovery made by the team is that while our galaxy rotates like a wheel, the BRAVA study found that the rotation of the central bar is more like that of a roll of paper towels in a dispenser. The team’s discoveries provide vital clues to help explain the formation of the Milky Way’s central region.

BRAVA data. Image Credit: D. Talent, K. Don, P. Marenfeld & NOAO/AURA/NSF and the BRAVA Project

The spectra data set was compared to a computer simulation created by Dr. Juntai Shen (Shanghai Observatory) showing how the bar formed from a pre-existing disk of stars. The team’s data fits the model quite well, suggesting that before the central bar existed, there was a massive disk of stars. The conclusion reached by the team is in stark contrast to the commonly accepted model of formation of our galaxy’s central region – a model that predicts the Milky Way’s central region formed from an early chaotic merger of gas clouds. The “take-away” point from the team’s conclusions is that gas did play some role in the formation of our galaxy’s central region, which organized into a massive rotating disk, and then turned into a bar due to the gravitational interactions of the stars.

One other benefit to the team’s research is that stellar spectra data will allow the team to analyze the chemical composition of the stars. All stars are composed of mostly hydrogen and helium, but the tiny amounts of other elements (astronomers refer to anything past helium as “metals”) provides insight into the conditions present during a star’s formation.

The BRAVA team found that stars closest to the plane of the Milky Way Galaxy have fewer “metals” than stars further from its galactic plane. The team’s conclusion does confirm standard views of stellar formation, yet the BRAVA data covers a significant area of the galactic bulge that can be chemically analyzed. If researchers map the metal content of stars throughout the Milky Way, a clear picture of stellar formation and evolution emerges, similar to how mapping CO2 concentrations in the Antarctic ice shelf can reveal the past weather patterns here on Earth.

If you’d like to read the full paper, a pre-print version is available at: http://arxiv.org/abs/1112.1955

Source: National Optical Astronomy Observatory press release

Posted on by Tammy Plotner

In The Dragonfish’s Mouth – The Next Generation Of “SuperStars”

A high-resolution infrared image of Dragonfish association, showing the shell of hot gas. Credit:NASA/JPL-Caltech/GLIMPSE Team/Mubdi Rahman

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At the University of Toronto, a trio of astronomers have been fishing – fishing for a copious catch of young, supermassive stars. What they caught was unprecedented… Hundreds of thousands of stars with several hundreds of these being the most massive kind. They hauled in blue stars dozens of times heavier than the Sun, with light so intense it ate its way through the gas that created it. All that’s left is the hollow egg-shell… A shell that measures a hundred light years across.

Their work will be published in the December 20 issue of the Astrophysical Journal Letters, but the team isn’t stopping there. The next catch is waiting. “By studying these supermassive stars and the shell surrounding them, we hope to learn more about how energy is transmitted in such extreme environments,” says Mubdi Rahman, a PhD candidate in the Department of Astronomy & Astrophysics at the University of Toronto. Rahman led the team, along with supervisors, Professors Dae-Sik Moon and Christopher Matzner.

Is the discovery of a huge factory for massive stars new? No. Astronomers have picked them up in other galaxies, but the distance didn’t allow for a clear picture – even when combined with data from other telescopes. “This time, the massive stars are right here in our galaxy, and we can even count them individually,” Rahman says.

However, studying this bright stellar cache isn’t going to be an easy task. Since they are located some 30,000 light years away, the measurements will be extremely labor intensive due to intervening gas and dust. Their light is absorbed, which makes the most luminous of them seem to be smaller and closer. To make matters worse, the fainter stars don’t show up at all. “All this dust made it difficult for us to figure out what type of stars they are,” Rahman says. “These stars are incredibly bright, yet, they’re very hard to see.”

By employing the New Technology Telescope at the European Southern Observatory in Chile, the researchers gathered as much light as possible from a small collection of stars. From this point, they calculated the amount of light each star emitted across the spectrum to determine how many were massive. At least twelve were of the highest order, with a few measuring out to be around a hundred times more massive than the Sun. Before researching the area with a ground-based telescope, Rahman used the WMAP satellite to study the microwave band. There he encountered the glow of the heated gas shell. Then it was Spitzer time… and the imaging began in infra-red.

Once the photos came back the picture was clear… Rahman noticed the stellar egg-shell had a striking resemblance to Peter Shearer’s illustration “The Dragonfish”. And indeed it does look like a mythical creature! With just a bit of imagination you can see a tooth-filled mouth, eyes and even a fin. The interior of the mouth is where the gas has been expelled by the stellar light and propelled forward to form the shell. Not a sight you’d want to encounter on a dark night… Or maybe you would!

“We were able to see the effect of the stars on their surroundings before seeing the stars directly,” Rahman says. This strange heat signature would almost be like watching a face lit by a fire without being able to see the fueling source. Just as red coals are cooler than blue flame, gas behaves the same way in color – with much of it in the infra-red end of the spectrum and only visible to the correct instrumentation. At the other end of the equation are the giant stars which emit in ultra-violet and remain invisible in this type of image. “But we had to make sure what was at the heart of the shell,” Rahman says.

With the positive identification of several massive stars, the team knew they would expire quickly in astronomical terms. “Still, if you thought the inside of the shell was empty, think again,” explains Rahman. For every few hundred superstars, thousands of ordinary stars like the Sun also exist in this region. When the massive ones go supernova, they’ll release metals and heavy atoms which – in turn – may create solar nebulae around the less dramatic stars. This means they could eventually form solar systems of their own

“There may be newer stars already forming in the eyes of the Dragonfish,” Rahman says. Because some areas of the shell appear brighter, researchers surmise the gases contained there are possibly compressing enough to ignite new stars – with enough to go around for many more. However, when there’s no mass or gravity to hold them captive, it would seem they want to fly the nest. “We’ve found a rebel in the group, a runaway star escaping from the group at high speed,” Rahman says. “We think the group is no longer tied together by gravity: however, how the association will fly apart is something we still don’t understand well.”

Original Story Source: In The Dragonfish’s Mouth: The Next Generation Of Superstars To Stir Up Our Galaxy.

Posted on by Ray Sanders

Astronomers Discover Ancient ‘Ultra-Red’ Galaxies

This artist's conception portrays four extremely red galaxies that lie almost 13 billion light-years from Earth. Discovered using the Spitzer Space Telescope, these galaxies appear to be physically associated and may be interacting. One galaxy shows signs of an active galactic nucleus, shown here as twin jets streaming out from a central black hole. Image Credit: David A. Aguilar (CfA)

[/caption]A team of astronomers, led by Jiasheng Huang (Harvard-Smithsonian Center for Astrophysics) using the Spitzer Space Telescope, have discovered four ‘Ultra-Red’ galaxies that formed when our Universe was about a billion years old. Huang and his team used several computer models in an attempt to understand why these galaxies appear so red, stating, “We’ve had to go to extremes to get the models to match our observations.”

The results of Huang’s research were recently published in The Astrophysical Journal

Using the Spitzer Space Telescope helped make the discovery possible, as it is more sensitive to infrared light than other space telescopes such as the Hubble. The newly discovered galaxies are sixty times brighter in the infrared than they are at the longest/reddest wavelengths HST can detect.

What processes are at work to create these extremely red objects, and why are they of interest to astronomers?

There are several reasons a galaxy could be reddened. For starters, extremely distant galaxies can have their light “redshifted” due to the expansion of the universe. If a galaxy contains large amounts of dust, it will also appear redder than a galaxy with less dust. Lastly, older galaxies will tend to be redder, due to a higher concentration of old, red stars and less younger bluer stars.

According to the paper, Huang and his team created three models to determine why these galaxies appear so red. Of their models, the one which suggests an old stellar population is currently the best fit to the observations. Supporting this conclusion, co-author Giovanni Fazio stated, “Hubble has shown us some of the first protogalaxies that formed, but nothing that looks like this. In a sense, these galaxies might be a ‘missing link’ in galactic evolution”.

Studying these extremely distant galaxies helps provide astronomers with a better understanding of the early universe, specifically how early galaxies formed and what conditions were present when some of the first stars were created. The next step in understanding these “ERO” galaxies is to obtain an accurate redshift for the galaxies, by using more powerful telescopes such as the Large Millimeter Telescope or Atacama Large Millimeter Array.

Huang and his team have plans to search for more galaxies similar to the four recently discovered by his team. Huang’s co-author Giovanni Fazio adds, “There’s evidence for others in other regions of the sky. We’ll analyze more Spitzer and Hubble observations to track them down.”

If you’d like to learn more, you can access the full paper (via arXiv.org) at: http://arxiv.org/pdf/1110.4129v1

Source: Harvard-Smithsonian Center for Astrophysics press release , arxiv.org

Posted on by Tammy Plotner

SOFIA Reveals Star-Forming Region W40

This mid-infrared image of the W40 star-forming region of the Milky Way galaxy was captured recently by the FORCAST instrument on the 100-inch telescope aboard the SOFIA flying observatory. (NASA / FORCAST image)

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Around 1957 light years away, a dense molecular cloud resides beside an OB star cluster locked in a massive HII region. The hydrogen envelope is slowly beginning to billow out and separate itself from the molecular gas, but we’re not able to get a clear picture of the situation thanks to interfering dust. However, by engaging NASA’s Stratospheric Observatory for Infrared Astronomy (SOFIA), we’re now able to take one of the highest resolution mid-infrared looks into the heart of an incredible star-forming region known as W40 so far known to science.

Onboard a modified 747SP airliner, the Faint Object infraRed Camera for the SOFIA Telescope (FORCAST) has been hard at work utilizing its 2.5 meter (100″) reflecting telescope to capture data. The composite image shown above was taken at wavelengths of 5.4, 24.2 and 34.8 microns. Why this range? Thanks to the high flying SOFIA telescope, we’re able to clear Earth’s atmosphere and “get above” the ambient water vapor which blocks the view. Not even the highest based terrestrial telescope can escape it – but FORCAST can!

With about 1/10 the UV flux of the Orion Nebula, region W40 has long been of scientific interest because it is one of the nearest massive star-forming regions known. While some of its OB stars have been well observed at a variety of wavelengths, a great deal of the lower mass stars remain to be explored. But there’s just one problem… the dust hides their information. Thanks to FORCAST, astronomers are able to peer through the obscuration at W40’s center to examine the luminous nebula, scores of neophyte stars and at least six giants which tip the scales at six to twenty times more massive than the Sun.

Why is studying a region like W40 important to science? Because at least half of the Milky Way’s stellar population formed in similar massive clusters, it is possible the Solar System also “developed in such a cluster almost 5 billion years ago”. The stars FORCAST measures aren’t very bright and intervening dust makes them even more dim. But no worries, because this type of study cuts them out of dust that’s only carrying a temperature of a few hundred degrees. All that from a flying observatory!

Now, that’s cool…

Original Story Source: NASA/SOFIA News. For Further Reading: The W40 Cloud Complex and A Chandra Observation of the Obscured Star-Forming Complex W40.