Posted on by Tammy Plotner

Baby Black Holes Grew Up Fast

This composite image from NASA's Chandra X-ray Observatory and Hubble Space Telescope (HST) combines the deepest X-ray, optical and infrared views of the sky. X-ray: NASA/CXC/U.Hawaii/E.Treister et al; Infrared: NASA/STScI/UC Santa Cruz/G.Illingworth et al; Optical: NASA/STScI/S.Beckwith et al

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For more than six weeks, the watchful eye of NASA’s Chandra X-ray Observatory kept track of a small portion of sky dubbed the Chandra Deep Field South (CDFS). Its object was to research 200 distant galaxies dating back to about 800 million to 950 million years old. What Chandra was looking for was evidence of massive black holes. The deepest evidence yet…

When combined with very deep optical and infrared images from NASA’s Hubble Space Telescope, the new Chandra data leads astronomers to speculate that young black holes may have evolved in unison with their young galaxies. “Until now, we had no idea what the black holes in these early galaxies were doing, or if they even existed,” said Ezequiel Treister of the University of Hawaii, lead author of the study appearing in the June 16 issue of the journal Nature. “Now we know they are there, and they are growing like gangbusters.”

What does this new information mean? The massive growth of the black holes in the CDFS are just shy of being a quasar – the super-luminous by-product of material slipping over the event horizon. “However, the sources in the CDFS are about a hundred times fainter and the black holes are about a thousand times less massive than the ones in quasars.” How often did it occur in the new data? Try between 30 and 100% of the case studies, resulting in a estimated 30 million supermassive black holes in the early Universe.

“It appears we’ve found a whole new population of baby black holes,” said co-author Kevin Schawinski of Yale University. “We think these babies will grow by a factor of about a hundred or a thousand, eventually becoming like the giant black holes we see today almost 13 billion years later.”

While the existence of these early black holes had been predicted, no observation had been made until now. Due to their natural “cloaking devices” of gas and dust, optical observation had been prohibited, but x-ray signatures don’t lie. The concept of tandem black hole / galaxy growth has been studied closer to home, but taking a look further back into time and space has revealed growth a hundred times more than estimated. These new Chandra results are teaching us that this connection begins at the beginning.

“Most astronomers think in the present-day universe, black holes and galaxies are somehow symbiotic in how they grow,” said Priya Natarajan, a co-author from Yale University. “We have shown that this codependent relationship has existed from very early times.”

Theories also abound which imply neophyte black holes may have played “an important role in clearing away the cosmic “fog” of neutral, or uncharged, hydrogen that pervaded the early universe when temperatures cooled down after the Big Bang”. But to the contrary, the new Chandra findings point towards the pervasive materials stopping ultraviolet radiation before the re-ionization process can occur. Resultant stars and dormant black holes are the most likely culprit to have cleared space for the cosmic dawn.

Although the Chandra X-ray Observatory is up to the task of picking up on uber-faint objects at incredible distances, these baby black holes are so veiled that only a few photons can slip through, making individual detection impossible. To gather this new data, the team employed Chandra’s directional abilities and tallied the hits near the positions of distant galaxies and found a statistically significant signal.

Original Story Source: Chandra News.

Posted on by Nancy Atkinson

Could You Head Up DARPA’s 100-Year Starship Program?

Will humanity one day boldly go... somewhere? Credit: Paramount.

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Since January of this year, DARPA and NASA have been publicly talking about a 100-year starship program. They’ve held a symposium, put out an official Request for Information (RFI) looking for ideas about how a long-term human mission to boldly go out to the stars could possibly happen, they have an official website and have just put out a request for papers for a public symposium that will be held this fall in Orlando, Florida.

Yes, they are serious about this.

However, contrary to what the title of the project might infer, it’s not so much about actually building a starship that could go on a long duration, long distance journey, but more about solving the all the various technical, medical, sociological and economic problems so that one day – perhaps in a 100 years or so – we actually could build one and head for the stars.

And they are looking for someone to head up the program.

“This is really a hard problem and I wouldn’t suggest for a second that it would be easy”, said David Neyland, director of the Tactical Technology Office for DARPA who spoke with reporters in a teleconference on June 16, 2011. “But the ancillary developments along the way such as of all the technology development, innovations in energy, medicine, agriculture, and socio and environmental issues, has direct payback to the Department of Defense and NASA, as well as the private and commercial sector.”

DARPA is known for its brand of “blue sky science” where the scientific research they do might not have apparent and initial real-world applications.

But with this project, DARPA and NASA are hoping to spur a surge reminiscent of the research, technology, and education — as well as the unintended consequences – that came about because of developments of the early space program.

“It’s the unpredictable and ancillary things that are of benefit for all of us,” Neyland said.

Neyland has been working with NASA Ames Director Pete Worden on the concept and Neyland said they chose the name not because they actually want to send a starship on a 100-year mission to space – although that would be the ultimate goal — but they want to capture the imagination of folks who normally wouldn’t think of doing research and development and tag them with something they would be excited about.

This is akin to how science fiction has spurred generations of scientists and engineers to follow the career paths they did.

Just like all the technology development that DARPA has done in the past which required only small initial investments but ultimately lead to things, such as the internet and GPS technology — as well as NASA’s investment in space travel which has spawned items we use every day here on Earth — they believe a small investment now could lead to a big payoff for everyone in the future.

So they are starting small. DARPA has put up $1 million and NASA has contributed $100,000 for one year of symposiums and study. $500,000 of that has been set aside and will be used as money for a grant given to the “winner” of their Request for Papers.

You can see the RFP at this link, and the deadline for paper abstracts and/or panel descriptions must be submitted online at www.100yss.org by 2:00 pm ET on Thursday, July 8, 2011.

The recipient of the grant could be an individual or corporation who has the best proposal for how to execute and nurture the R&D necessary for the 100-Year Starship program. “It will be a single grant of that amount which is startup money — seed money — to get the lights on, to get their footing to go out and start the cycle of investments and research, which hopefully becomes successful and then brings money back in so that more research can be done.”

After the grant is awarded, DARPA and NASA will step away, letting the winner set out and boldly go.
Neyland said he knows these are austere times, but feels this is a strong way to leverage investments for a good, ultimate payoff, even though that payoff may not be for several decades.

What type of person or corporation could possibly win this grant?

“Who would do this?” Neyland replied to the question that was posed by Universe Today. “Some folks want to send money to DARPA right now for this, and some want to sign up to be on the crew for the 100-year starship. But I don’t want to say who would be a respondent to the RFP, as we want to it be very ‘open kimono.’ But we want people to propose to us what would be the right path to take.”

Neyland mentioned successful long-term foundations such as the Rockfeller and Gugenhiem foundations might be an example of what the entity could ultimately turn into, but he doesn’t want to prejudice that there is a specific entity or construct they are looking for. “We want people to propose to us what the right direction should be,” he said. “They’ll have the ability to go in whatever direction they see fit.”

Neyland added this is not intended to be open to US citizens or corporations only – although there is a dilemma that he is not sure DARPA can give a grant to a foreign entity. “But this has to has a much broader view that what can happen in the US academic and industrial base,” he said. “ This has to be across all international boundaries, across all academia and all industries.”

Neyland admitted there is the possibility that no one will step forward far enough to earn the grant.

“We want to get the most bang for the buck for the Department of Defense,” he said.

So, everyone out there who has the dream of traveling to the stars, what are your ideas?

See the 100 Year Starship website for more information. The public symposium will be in Orlando, Florida on Sept. 30 – Oct. 2, 2011.

Here are the list of tracks the conference will include. Individuals may submit speaking abstracts directly related to these topics, or they can propose entirely different ideas.

• Time-Distance Solutions [propulsion, time/space manipulation and/or dilation, near speed of light navigation, faster than light navigation, observations and sensing at near speed of light or faster than light]
• Education, Social, Economic and Legal Considerations [education as a mission, who goes, who stays, to profit or not, economies in space, communications back to earth, political ramifications, round-trip legacy investments and assets left behind]
• Philosophical, and Religious Considerations [why go to the stars, moral and ethical issues, implications of finding habitable worlds, implications of finding life elsewhere, implications of being left behind]
• Biology and Space Medicine [physiology in space, psychology in space, human life suspension (e.g., cryogenic), medical facilities and capabilities in space, on-scene (end of journey) spawning from genetic material]
• Habitats and Environmental Science [to have gravity or not, space and radiation effects, environmental toxins, energy collection and use, agriculture, self-supporting environments, optimal habitat sizing]
• Destinations [criteria for destination selection, what do you take, how many destinations and missions, probes versus journeys of faith]
• Communication of the Vision [storytelling as a means of inspiration, linkage between incentives, payback and investment, use of movies, television and books to popularize long term research and long term journeys]

You can follow Universe Today senior editor Nancy Atkinson on Twitter: @Nancy_A. Follow Universe Today for the latest space and astronomy news on Twitter @universetoday and on Facebook.

Posted on by Tammy Plotner

New Clues To Solving Physics Riddle

Credit: Univeristy of Tokyo

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There are diminutive visitors to Earth. We’ve known about them and measured their presence since the 1960s. When the Sudbury Neutrino Observatory (SNO) turned on in May, 1999 the world became acutely aware of tiny particles known as solar neutrinos. The facility gathered data for seven years before shutting down and we’ve heard little in the media about neutrinos since. As we know, mass cannot be either created nor destroyed – only converted – so where did it originate? Exciting results produced by the international T2K neutrino experiment in Japan may be key to resolving this riddle.

To understand neutrinos is to understand their flavors: the electron neutrino teamed by particle interactions with electrons, and two additional marriages with the muon and tau leptons. Through research, science has proved these different types of neutrinos can spontaneously change into each other, a phenomenon called ‘neutrino oscillation’. From this action, two types of oscillations have been documented during the T2K experiment, but a new format has come to light… the introduction of electron neutrinos in a muon neutrino beam. This means neutrinos can fluctuate in every way science can possibly dream of. These new findings point to the fact that oscillations of neutrinos and their anti-particles (called anti-neutrinos) could be different. If they are, this could be an example of what physicists call CP violation. This would be a tidy explanation of why our Universe breaks the laws of physics by having more matter than anti-matter.

Unfortunately, the T2K neutrino experiment was disrupted by this year’s devastating Japan earthquake. But the team was prepared and both they – and the equipment – weathered the catastrophe. Before shutting down, six pristine electron neutrino events were recorded where there should have only been 1.5. With odds of this happening only one in one hundred times, the team felt these findings weren’t conclusive to confirm a new physics discovery and so they listed their results as an “indication”.

Prof Dave Wark of STFC and Imperial College London, who served for four years as the International Co-Spokesperson of the experiment and is head of the UK group, explains, “People sometimes think that scientific discoveries are like light switches that click from ‘off’ to ‘on’, but in reality it goes from ‘maybe’ to ‘probably’ to ‘almost certainly’ as you get more data. Right now we are somewhere between ‘probably’ and ‘almost certainly’.”

Prof Christos Touramanis from Liverpool University is the Project Manager for the UK contributions to T2K: “We have examined the near detectors and turned some of them back on, and everything that we have tried works pretty well. So far it looks like our earthquake engineering was good enough, but we never wanted to see it tested so thoroughly.”

Prof Takashi Kobayashi of the KEK Laboratory in Japan and spokesperson for the T2K experiment, said “It shows the power of our experimental design that with only 2% of our design data we are already the most sensitive experiment in the world for looking for this new type of oscillation.”

And we’re looking forward to their findings!

Original Story Source: Science and Technology.

Posted on by Nancy Atkinson

Hubble’s Stunning New View of Centaurus A

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From a HubbleSite press release:

Resembling looming rain clouds on a stormy day, dark lanes of dust crisscross the giant elliptical galaxy Centaurus A. Hubble’s panchromatic vision, stretching from ultraviolet through near-infrared wavelengths, reveals the vibrant glow of young, blue star clusters and a glimpse into regions normally obscured by the dust.

The warped shape of Centaurus A’s disk of gas and dust is evidence for a past collision and merger with another galaxy. The resulting shockwaves cause hydrogen gas clouds to compress, triggering a firestorm of new star formation. These are visible in the red patches in this Hubble close-up.

At a distance of just over 11 million light-years, Centaurus A contains the closest active galactic nucleus to Earth. The center is home for a supermassive black hole that ejects jets of high-speed gas into space, but neither the supermassive or the jets are visible in this image.

This image was taken in July 2010 with Hubble’s Wide Field Camera 3.

Posted on by Jason Major

The Final Countdown: A Tweetup Journal

The last space shuttle: Atlantis awaits its final launch. Credit: NASA

On July 8, less than a month from now, the last remaining space shuttle is slated to launch from Cape Canaveral. The STS-135 mission will bring supplies and parts up to the International Space Station and will be the historic conclusion of the 30-year-long shuttle program.

Unless otherwise rescheduled, at 11:40am on Friday, July 8, the big clock will count down, the rocket boosters will ignite, the steam will billow and the shuttle Atlantis will roar into the sky for one final, glorious time.

And I’ll be there.

(*exhale*)

Continue reading “The Final Countdown: A Tweetup Journal”

Posted on by Nancy Atkinson

Lunar Eclipse Images from Around the World; June 15, 2011

A mosiac of lunar eclipse images by Marko Posavec in Koprivnica, Croatia.

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Now updated with more images and video!

It was an event that hasn’t happened in 11 years and won’t happen again until 2018. The total lunar eclipse of June 15, 2011 didn’t disappoint. Take a look at some of the amazing images taken by astrophotographers from around the world — well, the “eastern” side of the world anyway, as the eclipse wasn’t visible in North and South America. Our lead image is a fantastic mosaic taken by Marko Posavec in Koprivnica, Croatia. We have another image by Posavic below, but you can see more of his images via his Twitter account.

A blood red Moon as seen by Leonard E. Mercer in Malta.

The redness of the Moon during the eclipse was perhaps enhanced by the major volcanic eruption in Chile which has polluted the stratosphere with a haze, making the eclipse appear dark red. This image was taken by Leonard Mercer in Malta. You can see more of his images at his website.

The eclipsed Moon over buildings in Pisa, Italy. Credit: @UgoRom

Here’s a nice shot of the eclipsed Moon in Pisa, Italy, sent via Twitter from @UgoRom.

ISS flyby with an eclipsed Moon near the horizon in Koprivnica, Croatia. Credit: Marko Posavec

Here’s two skywatching events at once: and ISS flyby along with the eclipse, taken by Marko Posavec in Croatia.

Lunar eclipse from Germany. Credit: Daniel Fischer

Daniel Fischer from Germany, who writes the Cosmos4U blog and Skyweek German blog, took this image and said, “against all odds skies cleared *and* the geometry was better than expected about 10 minutes after totality. This is when this picture was taken, the reddish (outer) umbra still very evident.” You can read his recap of the eclipse here.

The June 15, 2011 lunar eclipse from South Australia. Credit: Julie Grise

Julie Grise from Adelaide in South Australia said “It clouded out here for totality – but between the clouds I managed a few images.”

Here’s a video from Nahum Chazarra, sent via Twitter taken from el Llano de la Perdiz, in Granada, Spain:

Lunar eclipse among the clouds in Vientiane, Lao PDR in southeast Asia. Credit: Janet Pontin
The red eclipsed Moon over Vientiane, Lao PDR in southeast Asia. Credit: Janet Pontin

The two images above are from Janet Pontin from Vientiane, Lao PDR in southeast Asia, who wrote to say, “We were very pleased that the thick clouds that had been sitting all evening cleared away, mostly, as the eclipse went underway. Complete view was from around 2.30 to 3am our time.”

Lunar eclipse. Credit: Gadi Eidelheit

Longtime UT reader Gadi Eidelheit from Israel took this image and said, “We had over 600 parents and children at the school where I did the observation.” A picture of Gadi and part of the group is below. He said the IAA (Israel Astronomy Association) volunteers operated about 30 observation places, and the eclipse was covered in all major papers, TV networks and news sites.”

Over 600 gathered to watch the eclipse at a school in Israel. Picture courtesy Gadi Eidelheit
A panoramic view of the eclipse near Ankara, Turkey. Credit: M. Rasid Tugral.

This beautiful panorama was taken near Ankara, Turkey and sent in by M. Rasid Tugral.

The lunar eclipse over western Switzerland. Credit: Alistair Scott

This image from Switzerland was sent in by Alistair Scott, author of The Greatest Guide to Photography.

The Moon during the early part of the June 15, 2011 eclipse over Tehran, Iran. Credit: Saeed Amiri and Hadi Emami.
A red, eclipsed Moon over Tehran, Iran. Credit: Saeed Amiri and Hadi Emami.

The two images above were sent in by Saeed Amiri Hadi Emami in Tehran, Iran, who took them with Canon SX210 camera.

You can follow Universe Today senior editor Nancy Atkinson on Twitter: @Nancy_A. Follow Universe Today for the latest space and astronomy news on Twitter @universetoday and on Facebook.

Posted on by Tammy Plotner

Surf’s Up! Solar Wave Clocked At 4.5 Million Miles Per Hour

SDO/AIA images of fast waves on 2010 August 1

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Time to grab your silver surfboards because scientists utilizing the Atmospheric Imaging Assembly (AIA) instrument on-board NASA’s Solar Dynamics Observatory (SDO), have picked up on quasi-periodic waves in the low solar corona that travel at speeds as high as 2,000 kilometers per second (4.5 million miles per hour). Just think… We could ride that tasty wave to the Moon and back about 16 times during lunch break and still have time for coffee!

Presenting the findings today at the annual meeting of the Solar Physics Division of the American Astronomical Society is Dr. Wei Liu, a Stanford University Research Associate at the Lockheed Martin Solar and Astrophysics Laboratory (LMSAL) at the company’s Advanced Technology Center (ATC) in Palo Alto. His research has provided concrete evidence of propagating fast mode magnetosonic waves at such high speeds in the Sun’s low atmosphere. We’ve known for awhile that hot plasma will produce a “ripple effect” – much like a bubble popping to the surface when heating gravy. While computer simulations, models and theories speculated how it occurred, it wasn’t until now that these waves have been directly observed. Why? Because we simply weren’t quick enough.

“It is the high temporal and spatial resolution of AIA that enables us to see these waves clearly for the first time. AIA takes high sensitivity, extreme ultraviolet (EUV) pictures of the solar corona at spatial scales down to 1,100 kilometers, every 12 seconds with 0.1-2 second exposures,” said Dr. Liu, who led the analysis of the waves. “In addition, AIA’s full Sun field of view at seven simultaneous wavelengths allows us to track them over large spatial and temperature ranges.”

Just check this bad boy out…

Lasting anywhere from 30 to 200 seconds, the hot arches center around flare nuggets and follow the wake of coronal mass ejection areas… traveling along the magnetic loops. “Their characteristic spatial and temporal scales and dispersion relation agree with theoretical expectations of fast mode magnetosonic waves, and are reproduced in our high fidelity 3D computer simulations,” said Prof. Leon Ofman of the Catholic University of America, part of the team that made the discovery. “They seem to be a common phenomenon. During the first year of the SDO mission, despite the Sun being relatively quiet, we have seen about a dozen such waves,” said Dr. Karel Schrijver, principal physicist of LMSAL. “Although their exact trigger mechanism is currently under investigation, they appear to be intimately related to flares that sometimes exhibit pulsations at similar frequencies.”

These types of waves are quite probably responsible for elemental – yet still mysterious – processes on the solar surface, such as heating the corona to millions of degrees, accelerating the solar wind, triggering remote eruptions, and delivering energy and information between different parts of the atmosphere. Through direct observance, we’re able to begin to unravel the physics and advance our knowledge of the Sun-Earth connection.

“This discovery and analysis is very significant because we are witnessing phenomena of which we were previously unaware. In light of this discovery, the more we look at solar flares, the more of these waves we see, and as observation and analysis lead to insight, the better we will understand the processes involved,” said Dr. Alan Title, AIA Principal Investigator at LMSAL who first noticed the fast propagating waves in routine AIA movies. “The findings announced today are an example of the fruit of a two decade long collaboration, of which we are enormously proud, between Lockheed Martin and Stanford University.”

What a ride…

Original Story Source: Lockheed Martin Solar and Astrophysics Lab.

Posted on by Tammy Plotner

Voyager Pushes Boundary of Interstellar Space

The edge of the solar system. Image Credit: NASA/JPL-Caltech

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It may be some 10.8 billion miles from home, but Voyager 1 is sending back some surprising data from the edge Even more recent transmissions show the gallant probe is closer to interstellar space than ever. “We’ve reached the boundary of the heliosheath, Jim… and it ain’t dead.”

It has taken 34 years, but Voyager 1 has now defiantly encountered the edge – the area where the speed of the solar plasma has decreased from 150,000 miles an hour down to zero. As released in the June 16th issue of Nature, a team of Voyager scientists led by Stamatios Krimigis of the Johns Hopkins University Applied Physics Laboratory speculates “the outflow of the solar wind may have stopped because of the pressure from the interstellar magnetic field in the region between stars.”

For the last three years the incredible little probe has been busy overseeing the predominant part of the plasma’s velocity in the heliosheath – a virtual pool of energetic ions and electrons. Now measurements have slipped from 40 miles per second to zero. This was first noted in April when Voyager’s speed matched the assessments.

“This tells us that Voyager 1 may be close to the heliopause, or the boundary at which the interstellar medium basically stops the outflow of solar wind,” says Krimigis, principal investigator for Voyager’s Low-Energy Charged Particle instrument. “The extended transition layer of near-zero outflow contradicts theories that predict a sharp transition to the interstellar flow at the heliopause – and means, once again, we will need to rework our models.”

Because we’re literally breaking new science ground, these new findings on velocities could fluctuate – meaning that more monthly readings are in order. When will we know? A good indicator would be when hot particles turn cold… a signal that interstellar space has been breached. This could occur as soon as the end of 2012.

Just another reason we might be around just a little bit longer…

Original Story Source: John Hopkins University Applied Physics Lab News.

Posted on by Tammy Plotner

Ovation For A Stellar Senior

IRAS 22036+5306 - Credit: ESA/Hubble/NASA

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Residing in space 6500 light-years away in the constellation of Cepheus, an aged star designated as IRAS 22036+5306 is making its final curtain call. Its stellar play is ending and its making the transition through the protoplanetary, or preplanetary, nebula phase. This isn’t an unusual occurrence, but considering we’ve only been able to witness perhaps a few hundred such events out of the millions of stars we’ve observed – it is a rare visual example. Behold a red giant turning into a white dwarf…

Kudos go to the watchful eye of the Hubble Space Telescope for capturing this ancient celestial oddity. Inside the elaborate enclosure of expelled material is an exposed stellar core – burning hotter than the aspirations of a young actor. Encircling it is a diaphanous cloak of composites – everything from comets to small, rocky bodies. Gases and clumps of material ten thousand times the mass of Earth rocket outward from the poles at speeds of up to 800 000 kilometres per hour. It is the last hurrah.

When its time has passed, IRAS 22036+5306 will transform into a planetary nebula. Intense ultraviolet radiation will ionise the cast-off gases and it will kindle the colorful spectacle which signals the low, slow cool-down until its next evolution. “Studying rarities such as IRAS 22036+5306 provides astronomers with a window into the short and poorly understood phase of stellar evolution when bloated red giant stars pare down to small white dwarfs.” says the ESA/Hubble/NASA team. “For example, mysteries remain about how exactly the dusty torus and jets form.”

Transforming into a planetary nebula may be what awaits the star of our own solar system play – as it is thought to be the eventual destiny of most medium-sized stars. But, our stellar actor might not exit with such splendor since IRAS 22036+5306 is roughly four times the size of the Sun.

And it’s a round of applause we’ll be waiting on for another 5 billion years…

Posted on by Jon Voisey

How Much Do Binary Stars Shape Planetary Nebulae?

A Collectionf of Planetary Nebulae from the HST
A Collectionf of Planetary Nebulae from the HST

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Planetary nebulae come in a dazzling array of shapes, from spherical shells of gas, to blobby structures barely containing symmetry at all. Controversy has surrounded the cause for this diversity. Could it be magnetic fields, high rotation rates, unseen companions, or something else entirely? Recently, there has been a growing consensus that binary companions are the main culprit for the most irregular of these nebulae, but exploring the connection is only possible with a statistically significant sample of planetary nebulae with binary cores can be found, giving hints as to what properties they may, or may not, create.

Currently, astronomers recognize over 3,000 planetary nebulae within our own galaxy. Only ~40 are known to harbor binary stars at their core but astronomers are uncertain of just how many truly due. The difficulty lies in the amount of time it takes to search for a companion. Typically, companions can be discovered with spectroscopic measurements in the same way astronomers discover planets by detecting a wobble. Alternatively, binary companions can be teased out through eclipses but both methods require frequent monitoring and, until recently, were best suited for single target studies.

With the recent popularity of wide field survey missions, possibilities to detect more binary companions has increased greatly. These surveys are ideally suited for capturing eclipses or microlensing events. In each case, they will preferentially discover companions with tight orbits and short orbital periods which are suspected to have the greatest effect on the shape of the nebulae.

Stars that orbit close together are expected to have a strong effect because, as the primary star enters its post-main sequence lifetime, it is likely that the secondary star will become engulfed in the envelope of the primary, essentially sharing the outer layers. This creates large differences in density along the equator which leads to uneven ejection of the material as the primary star sheds its outer layers, forming the nebula. These temporary overdensities would serve to funnel material and could be responsible for the presence of polar outflows or jets.

NGC 6326 Credit: ESA/Hubble and NASA
NGC 6326 Credit: ESA/Hubble and NASA

A recent study has added two more planetary nebulae to the list of those with known binary centers: NGC 6326 (shown right) and NGC 6778. Collimated outflows and jets were discovered in both cases. The authors also note that both nebulae have filaments with low ionization. Such structures have been noted previously, but their cause has remained uncertain. A 2009 study suggested that they may be the result of tight binaries, a hypothesis that is strengthened by the the new discovery. The overall shape of NGC 6326 is mostly elliptical while NGC 6778 is bipolar.