Hubble Image: Bizarre alignment of planetary nebulae

This image shows an example of a bipolar planetary nebula known as PN Hb 12 -- popularly known as Hubble 12 -- in the constellation of Cassiopeia. 

The striking shape of this nebula, reminiscent of a butterfly or an hourglass, was formed as a Sun-like star approached the end of its life and puffed its outer layers into the surrounding space. 

For bipolar nebulae, this material is funnelled towards the poles of the ageing star, creating the distinctive double-lobed structure. 

Credit: NASA, ESA Acknowledgement: Josh Barrington

Astronomers have used the NASA/ESA Hubble Space Telescope and ESO's New Technology Telescope to explore more than 100 planetary nebulae in the central bulge of our galaxy.

They have found that butterfly-shaped members of this cosmic family tend to be mysteriously aligned—a surprising result given their different histories and varied properties.

The final stages of life for a star like our Sun result in the star puffing its outer layers out into the surrounding space, forming objects known as planetary nebulae in a wide range of beautiful and striking shapes.

One type of such nebulae, known as bipolar planetary nebulae, create ghostly hourglass or butterfly shapes around their parent stars.

All these nebulae formed in different places and have different characteristics. Neither the individual nebulae, nor the stars that formed them, interact with other planetary nebulae.

However, a new study by astronomers from the University of Manchester, UK, now shows surprising similarities between some of these nebulae: many of them line up in the sky in the same way.

"This really is a surprising find and, if it holds true, a very important one," explains Bryan Rees of the University of Manchester, one of the paper's two authors.

"Many of these ghostly butterflies appear to have their long axes aligned along the plane of our galaxy. By using images from both Hubble and the NTT we could get a really good view of these objects, so we could study them in great detail."

The astronomers looked at 130 planetary nebulae in the Milky Way's central bulge. They identified three different types, and peered closely at their characteristics and appearance.

"While two of these populations were completely randomly aligned in the sky, as expected, we found that the third—the bipolar nebulae—showed a surprising preference for a particular alignment," says the paper's second author Albert Zijlstra, also of the University of Manchester.

"While any alignment at all is a surprise, to have it in the crowded central region of the galaxy is even more unexpected."

Planetary nebulae are thought to be sculpted by the rotation of the star system from which they form.

This is dependent on the properties of this system—for example, whether it is a binary, or has a number of planets orbiting it, both of which may greatly influence the form of the blown bubble.

The shapes of bipolar nebulae are some of the most extreme, and are thought to be caused by jets blowing mass outwards from the star system perpendicular to its orbit.

"The alignment we're seeing for these bipolar nebulae indicates something bizarre about star systems within the central bulge," explains Rees.

"For them to line up in the way we see, the star systems that formed these nebulae would have to be rotating perpendicular to the interstellar clouds from which they formed, which is very strange."

While the properties of their progenitor stars do shape these nebulae, this new finding hints at another more mysterious factor.

Along with these complex stellar characteristics are those of our Milky Way; the whole central bulge rotates around the galactic centre.

This bulge may have a greater influence than previously thought over our entire galaxy—via its magnetic fields.

The astronomers suggest that the orderly behaviour of the planetary nebulae could have been caused by the presence of strong magnetic fields as the bulge formed.

As such nebulae closer to home do not line up in the same orderly way, these fields would have to have been many times stronger than they are in our present-day neighbourhood.

"We can learn a lot from studying these objects," concludes Zijlstra. "If they really behave in this unexpected way, it has consequences for not just the past of individual stars, but for the past of our whole galaxy."

More information: 
Research paper: www.spacetelescope.org/static/archives/releases/science_papers/heic1315a.pdf

ESA Launch preparations begin for Gaia galaxy-mapper

Artist's concept of the Gaia spacecraft. 

Credit: ESA/ ATG medialab; background image: ESO/S. Brunier

Europe’s new eye on the galaxy arrived in French Guiana on Friday, beginning three months of flight preparations before liftoff on a Soyuz rocket in November to commence a survey of a billion stars and chart their chaotic motion in the Milky Way galaxy.

The Gaia observatory will be stationed a million miles from Earth, its dual telescopes sweeping across the sky with the sensitivity to plot the exact locations and movements of stars, detect the signatures of alien worlds, and spot icy dwarf planets on the outer frontier of the solar system.

The breadth of Gaia’s scientific promise ranges from scanning the Milky Way to create a three-dimensional map of the galaxy to the discovery of asteroids in Earth's neighborhood.

Scientists say Gaia could return data leading to the discovery of up to 2,000 planets around other stars – mostly Jupiter-sized gas giants.

And the European space mission has the precision to test tenets of Albert Einstein’s theory of general relativity by observing how the pull of the sun and planets bend starlight before it reaches Gaia’s apertures.

In five years, Gaia will collect a petabyte of data, enough to fill 1.5 million compact discs. It will see a billion stars, more than ever observed by any other mission, and use information about those objects to study the origin and evolution of the Milky Way.

“The estimate of the number of stars in the Milky Way is between 100 and 200 billion stars, so we observe between one-half and one percent of these stars,” said Timo Prusti, Gaia’s project scientist at the European Space Agency.

“Because of the completeness of Gaia to a limiting magnitude, this proving of 1 percent of these objects will help us reconstruct the remaining part. We’re not going to take a full census of the Milky Way, but we are going to look at a billion stars and we’ll have enough statistical power to deduce the structure of the Milky Way.”

A team of scientists and engineers has worked on Gaia since the mission was approved by the European Space Agency in 2000. The mission’s cost is 740 million euros, or approximately $990 million.

After of 13 years of development, design reviews, construction and testing, Gaia is one step closer to the launch pad.

Liftoff is scheduled for Nov. 20 at 0857 GMT (3:57 a.m. EST; 5:57 a.m. local time) aboard a Europeanized version of Russia’s Soyuz rocket.

The mission will mark the seventh flight of a Soyuz booster from French Guiana, and a Fregat upper stage will propel Gaia on a trajectory toward the L2 Lagrange point about a million miles from the night side of Earth, where gravity from the Earth and sun balance a satellite’s motion.

JAXA HTV departure from ISS to test revised robotic Dextre operations plan

The JAXA HTV 4 spacecraft is pictured with the Canadian robot arm and Dextre. Credit: NASA

Japan's fourth H-2 Transfer Vehicle will leave the International Space Station on Wednesday, and the astronauts in charge of releasing the unmanned cargo carrier will use a new technique to keep the HTV steady and avoid the recurrence of a hair-trigger abort that expedited the departure of a previous mission.

Filled with trash and other unneeded gear, the HTV will be released from the space station's 58-foot robotic arm at about 12 p.m. EDT (1600 GMT) Wednesday.

Using a control panel inside the space station, astronauts will command the HTV to retreat from the complex a few minutes later, beginning a preprogrammed sequence of two separation burns with the ship's rocket thrusters.

Space station flight engineers Karen Nyberg and Luca Parmitano closed the HTV's hatches Tuesday to prepare for the departure.

The robotic cargo freighter delivered 3.6 tons of supplies and experiments to the space station Aug. 9 after a five-day transit from a Japanese launch pad to the orbiting outpost.

The astronauts unpacked food, spare parts, experiments and other equipment from the HTV's pressurized compartment, while ground controllers put two robotic arms and a two-armed robotic handyman to work outside the space station to handle the spacecraft's cache of external cargo.

The Canadian-built Dextre robot stowed a main bus switching unit, utility transfer assembly, and an experiment package sponsored by the U.S. Defense Department on platforms mounted on the space station's truss.

Dextre retrieved an older U.S. military experiment - part of the Air Force's Space Test Program - and placed it on the HTV's exposed cargo pallet, then the platform was put back inside the cargo craft Aug. 30.

The trash and experiment box packed inside the HTV will be destroyed during re-entry over the Pacific Ocean on Saturday.

Perched on the end of the station's Canadian robot arm, the HTV will be removed from its berthing port on the Harmony module early Wednesday and maneuvered to a location about 30 feet below the complex.

When astronauts get the go to release the 33-foot-long spacecraft, they will follow a new plan devised after trouble encountered when the third HTV left the space station in September 2012.

After its release from the robot arm, the HTV 3 spacecraft began to drift outside of a predetermined box. Its on-board computers sensed the unplanned movement.

"When we released it with the arm, it imparted a moment on the spacecraft, which caused the spacecraft to translate a little bit," said Mike Suffredini, NASA's space station program manager.

"The abort itself was required because of the moment put on it with the arm. The big thing about the abort was it used the main engines, which put a higher plume and heating load out there close to ISS. Both of those issues have been dealt with between then and now," Suffredini said.

NASA Cassini: Massive Saturn Storm Pulls Water and Ammonia Ices from the Depths

This series of images from NASA’s Cassini spacecraft shows the development of the largest storm seen on the planet since 1990. 

These true-colour and composite near-true-color views chronicle the storm from its start in late 2010 through mid-2011, showing how the distinct head of the storm quickly grew large but eventually became engulfed by the storm’s tail. 

Credit: NASA /JPL-Caltech /Space Science Institute

Once every 30 years or so, or roughly one Saturnian year, a monster storm rips across the northern hemisphere of the ringed planet.

In 2010, the most recent and only the sixth giant storm on Saturn observed by humans began stirring. It quickly grew to superstorm proportions, reaching 15,000 kilometers (more than 9,300 miles) in width and visible to amateur astronomers on Earth as a great white spot dancing across the surface of the planet.

Now, thanks to near-infrared spectral measurements taken by NASA's Cassini orbiter and analysis of near-infrared colour signatures by researchers at the University of Wisconsin-Madison, Saturn's superstorm is helping scientists flesh out a picture of the composition of the planet's atmosphere at depths typically obscured by a thick high-altitude haze.

The key finding: cloud particles at the top of the great storm are composed of a mix of three substances: water ice, ammonia ice, and an uncertain third constituent that is possibly ammonium hydrosulphide.

According to the Wisconsin researchers, the observations are consistent with clouds of different chemical compositions existing side-by-side, although a more likely scenario is that the individual cloud particles are composed of two or all three of the materials.

Writing in the current edition (Sept. 9, 2013) of the journal Icarus, a team led by UW-Madison Space Science and Engineering Center planetary scientists Lawrence Sromovsky, and including Kevin Baines and Patrick Fry, reports the discovery of the icy forms of water and ammonia.

Water in the form of ice has never before been observed on Saturn.

"We think this huge thunderstorm is driving these cloud particles upward, sort of like a volcano bringing up material from the depths and making it visible from outside the atmosphere," explains Sromovsky, a senior scientist at UW-Madison and an expert on planetary atmospheres.

"The upper haze is so optically pretty thick that it is only in the stormy regions where the haze is penetrated by powerful updrafts that you can see evidence for the ammonia ice and the water ice. Those storm particles have an infrared colour signature that is very different from the haze particles in the surrounding atmosphere."

"The water could only have risen from below, driven upward by powerful convection originating deep in the atmosphere. The water vapor condenses and freezes as it rises. It then likely becomes coated with more volatile materials like ammonium hydrosulfide and ammonia as the temperature decreases with their ascent," Sromovsky adds.

The interesting effect, he notes, is that in Saturn's massive storm, at least, the observations can be matched by having particles of mixed composition, or clouds of water ice existing side-by-side with clouds of ammonia ice.

In the latter scenario, water ice would make up 22 percent of the cloud head and ammonia ice 55 percent.

The remaining fraction would be made up by the third constituent, which though less certain, is believed to be ammonia hydrosulfide.

"Up until now, there have been no quantitative calculations of spectra for cloud structures and compositions that matched the observed spectrum of an actual storm cloud feature," says Sromovsky.

Journal Reference:
L.A. Sromovsky, K.H. Baines, P.M. Fry. Saturn’s Great Storm of 2010–2011: Evidence for ammonia and water ices from analysis of VIMS spectra. Icarus, 2013; 226 (1): 402 DOI: 10.1016/j.icarus.2013.05.043

NASA Cassini Image: Saturn Storm's Explosive Power

This set of images from NASA's Cassini mission shows the turbulent power of a monster Saturn storm. 

The visible-light image in the back, obtained on Feb. 25, 2011, by Cassini's imaging camera, shows the turbulent clouds churning across the face of Saturn.

The inset infrared image, obtained a day earlier, by Cassini's visual and infrared mapping spectrometer, shows the dredging up of water and ammonia ices from deep in Saturn's atmosphere.

This was the first time water ice was detected in Saturn's atmosphere. The storm, first detected by Cassini's radio and plasma wave subsystem in December 2011, churned around the planet in a band around 33 degrees north.

Image Credit: NASA/ JPL-Caltech/ SSI/ Univ. of Arizona/ Univ. of Wisconsin

Read the full article on NASA JPL Photojournal site

Dark Energy Survey (DES): Five-year mission to map southern sky in detail

This image of the NGC 1398 galaxy was taken with the Dark Energy Camera (DECam). 

This galaxy lives in the Fornax cluster, roughly 65 million light years from Earth. 

It is 135,000 light years in diameter, just slightly larger than our own Milky Way galaxy, and contains more than a hundred million stars. 

Credit: Dark Energy Survey.

Tonight, as the sun sinks below the horizon, the world's most powerful digital camera will once again turn its gleaming eye skyward.

Tonight, and for hundreds of nights over the next five years, a team of physicists and astronomers from around the globe will use this remarkable machine to try to answer some of the most fundamental questions about our universe.

Dark Energy Survey - DECam: Fermilab  

On Aug. 31, the Dark Energy Survey (DES) officially began. Scientists on the survey team will systematically map one-eighth of the sky (5000 square degrees) in unprecedented detail.

The start of the survey is the culmination of 10 years of planning, building and testing by scientists from 25 institutions in six countries.

The survey's goal is to find out why the expansion of the universe is speeding up, instead of slowing down due to gravity, and to probe the mystery of dark energy, the force believed to be causing that acceleration.

James Siegrist

"The Dark Energy Survey will explore some of the most important questions about our existence," said James Siegrist, associate director for High Energy Physics at the U.S. Department of Energy's Office of Science.

"In five years' time, we will be far closer to the answers, and far richer in our knowledge of the universe."

"With the start of the survey, the work of more than 200 collaborators is coming to fruition," said DES Director Josh Frieman of the U.S. Department of Energy's Fermi National Accelerator Laboratory.

"It's an exciting time in cosmology, when we can use observations of the distant universe to tell us about the fundamental nature of matter, energy, space and time."

Composite Dark Energy Camera image of one of the sky regions that the collaboration will use to study supernovae, exploding stars that will help uncover the nature of dark energy. 

The outlines of each of the 62 Charged Coupled Devices can be seen. 

This picture spans 2 degrees across on the sky and contains 520 megapixels.

The survey will use four methods to probe dark energy:

• Counting galaxy clusters. While gravity pulls mass together to form galaxies, dark energy pulls it apart. The Dark Energy Camera will see light from 100,000 galaxy clusters billions of light-years away. Counting the number of galaxy clusters at different points in time sheds light on this cosmic competition between gravity and dark energy.
• Measuring supernovae. A supernova is a star that explodes and becomes as bright as an entire galaxy of billions of stars. By measuring how bright they appear on Earth, we can tell how far away they are. Scientists can use this information to determine how fast the universe has been expanding since the star's explosion. The survey will discover 4000 of these supernovae, which exploded billions of years ago in galaxies billions of light-years away. 
• Studying the bending of light. When light from distant galaxies encounters dark matter in space, it bends around the matter, causing those galaxies to appear distorted in telescope images. The survey will measure the shapes of 200 million galaxies, revealing the cosmic tug of war between gravity and dark energy in shaping the lumps of dark matter throughout space.
• Using sound waves to create a large-scale map of expansion over time. When the universe was less than 400,000 years old, the interplay between matter and light set off a series of sound waves traveling at nearly two-thirds the speed of light. Those waves left an imprint on how galaxies are distributed throughout the universe. The survey will measure the positions in space of 300 million galaxies to find this imprint and use it to infer the history of cosmic expansion.

NASA's twin Van Allen Probes: 1st Anniversary - new discoveries and new investigations

Artist's rendition of Earth's radiation belts with the twin Van Allen Probes traveling through them. Credit: NASA

One year after their launch from Cape Canaveral Air Force Station at 4:05 a.m. E DT on Thursday, Aug. 30, 2012, NASA's twin Van Allen Probes have already fundamentally changed how we understand the Van Allen radiation belts above our planet.

Data from the probes have already led to several significant discoveries, some made just days after the special twin spacecraft soared into orbit.

The mission has answered one long-standing question about the nature and behavior of the belts, and revealed that the outer belt can split into two separate belts.

With this first year of discovery and enhancements in operations as a cornerstone, the science teams of the Van Allen Probes (formerly named the Radiation Belt Storm Probes) are looking forward to unlocking further mysteries and advancing our knowledge of particle physics and the dynamics of space plasmas, as well as how to better protect space-based technologies like satellites.

"The science results are coming fast now," says NASA's Mona Kessel, program scientist for the Van Allen Probes.

"Some of the discoveries we've made are going to rewrite the textbooks on the radiation belts. And while those discoveries are fascinating and merit more research, we're still focused on the question we asked when we designed the mission: What are the primary mechanisms of particle loss and acceleration in the belts? We're beginning to answer that now."

The radiation belts are two donut-shaped regions of highly energetic particles trapped in the Earth's magnetic field – the inner, located just above our atmosphere and extending 4,000 miles into space; and the outer, from 8,000 to 26,000 miles out – and are named for their discoverer (as are the probes), the late James A. Van Allen of the University of Iowa.

The belts' makeup and properties have affected both spaceflight and physics research for the past 50 years, and the Van Allen Probes were designed to answer a number of fundamental questions about these harsh regions of space.