Posted on by Tammy Plotner

Burned Out Stars Do A Deadly Last Dance

Two white dwarfs have been discovered on the brink of a merger. In just 900,000 years, material will start to stream from one star to the other (as shown in this artist's conception), beginning the process that may end with a spectacular supernova explosion. Watching these stars fall in will allow astronomers to test Einstein's general theory of relativity as well as the origin of a special class of supernovae. Credit: David A. Aguilar (CfA)

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“Well, I don’t know, but I’ve been told… You never slow down, you never grow old.” Well, Tom Petty might not ever grow old, but stars do. In this case it’s a pair white dwarf stars and they’re locked in a death dance that has them spiraling around each other in just 13 minutes. Astronomers estimated that in about 900,000 years the pair will merge… and what a party that will be!

Traveling in an orbit that’s currently carrying them at 370 miles per second (600 km/s), these two burnt-out stellar cores are heading towards a supernova ending. Right now the brighter of the pair is about the size of Neptune and carries about one quarter of our Sun’s mass. Its companion contains twice as much mass and is about the size of Earth. What’s peculiar is the incredible speed at which they are converging.

“I nearly fell out of my chair at the telescope when I saw one star change its speed by a staggering 750 miles per second in just a few minutes,” said Smithsonian astronomer Warren Brown, lead author of the paper reporting the find.

Using the MMT telescope at the Whipple Observatory on Mt. Hopkins, Arizona, researchers have been looking for just such eclectic white dwarf pairings. Because of their close proximity, they can only be separated spectroscopically and their relative motions then determined. Fortunately, this unusual set are eclipsing, doing their two-step at a very predictable rate. “If there were aliens living on a planet around this star system, they would see one of their two suns disappear every 6 minutes – a fantastic light show.” said Smithsonian astronomer and co-author Mukremin Kilic.

What’s really cool about this observing project is its implications as related to Einstein’s theories. Their movements should create wrinkles in the fabric space-time. These gravitational waves pull away at the energy – allowing the pair to get closer at each pass and their orbits to accelerate.

“Though we have not yet directly measured gravitational waves with modern instruments, we can test their existence by measuring the change in the separation of these two stars,” said co-author J. J. Hermes, a graduate student at the University of Texas at Austin. “Because they don’t seem to be exchanging mass, this system is an exceptionally clean laboratory to perform such a test.”

Just as soon as the pair emerges from behind the Sun, observing will begin again. Some models predict merging white dwarf pairs of this type could be a rare class of unusually faint stellar explosions called underluminous supernovae – or just the source of many other kinds of supernovae. “If these systems are responsible for underluminous supernovae, we will detect these binary white dwarf systems with the same frequency that we see the supernovae. Our survey isn’t complete, but so far, the numbers agree,” said Brown.

What can we say besides, “Last dance with Mary Jane… One more time to kill the pain… I feel summer creepin’ in.”

Original Story Source: Harvard-Smithsonian Center for Astrophysics.

Posted on by Nancy Atkinson

Share a Meal With Astronauts in Space on July 14

NASA's All American Meal the astronauts will eat on July 14, 2011. Credit: NASA

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I’m just making out my shopping list for going to the grocery store tomorrow, and it includes everything I need to share a virtual dinner with the astronauts in space on Thursday, July 14. And no, unfortunately, I’m not launching to the ISS to join them. Food scientists at NASA’s Johnson Space Center in Houston thought it would be fun to give the crew an “All American Meal” — a typical American meal for the final mission of the shuttle and invite the public to join in by preparing the same food. Whatever you prepare it will be more aesthetically pleasing than the rehydrated food in plastic bags the shuttle and ISS crews will eat. Here’s the menu:

An appetizer of brie cheese, crackers and sausage; your choice of grilled chicken (which the shuttle crew will eat) or beef brisket (which will be enjoyed by the ISS crew), Southwestern corn and baked beans. The ISS crew will have beef brisket instead of chicken, but will enjoy the same side dishes as the shuttle crew. Desert for both crews consists of apple pie. The meal concludes with the quintessential American dessert, apple pie.

“Since the mission is in July, we thought it would be fun to have a typical summer meal often enjoyed in our backyards with friends and family,” said Michele Perchonok, NASA food scientist and manager of the shuttle food system.

For the special space recipes or “formulations” as they are called by NASA food scientists, plus more information, video and imagery, visit this NASA webpage.

The crackers, brie, sausage and apple pie are commercial off-the-shelf products repackaged for spaceflight. NASA food scientists prepared the chicken, brisket, corn and beans in a laboratory at Johnson before the mission.

NASA didn’t specify what time the astronauts will be eating their All American Meal, so you can eat at any time during the day and know you’re eating the same thing as the astronauts in space did. Well, pretty close to the same thing anyway. Hopefully those of us sitting on Earth don’t have to rehydrate our food and eat out of plastic bags.

Posted on by Nancy Atkinson

Historic Images of Final Spacewalk of Shuttle Era

With space shuttle Atlantis docked to the space station for the STS-135 mission, the final EVA of the shuttle era took place on July 12, 2011. Here, Ron Garan is secured on a restraint on the space station remote manipulator system's robotic arm or Canadarm2, carrying a faulty pump module will be retuned to Earth by the shuttle. Credit: NASA

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It’s the end of an era: the final spacewalk during the space shuttle era was conducted by astronauts on July 12, 2011 during the final shuttle mission, STS-135. This is the 160th spacewalk supporting assembly and maintenance of the space station and the 249th EVA conducted by U.S. astronauts. The two spacwalkers were actually from the International Space Station crew, Expedition 28’s Mike Fossum and Ron Garan, but were assisted by the shuttle crew. Shuttle Pilot Doug Hurley and Mission Specialist Sandy Magnus operated operate the station’s 58-foot-long Canadarm 2 to maneuver the spacewalkers around during the spacewalk.

Here are more images from the EVA:


Astronaut Ron Garan egresses the Quest airlock on the International Space Station as he prepares to join crewmate Mike Fossum for the spacewalk. Credit: NASA

Mike Fossum works outside the ISS during the six and a half hour spacewalk, the final of the shuttle era. Credit: NASA.
No, this isn't a picture of an astronaut carrying a freezer outside the space station. With his feet secured on a restraint on the space station remote manipulator system's robotic arm Canadarm2, Mike Fossum holds the Robotics Refueling Mission payload, an experiment which will test in-flight refueling with the DEXTRE robot. Fossum and Ron Garan installed the experiment during the July 12 EVA. Credit: NASA
Suspended in a very unique position on the end of Canadarm2, Mike Fossum takes a picture during a July 12 spacewalk. Credit: NASA
Space shuttle Atlantis makes a cameo in this image as Mike Fossum takes a picture during the spacewalk while on a foot restraint on the Canadarm 2. Credit: NASA
Ron Garan during the spacewalk: "I almost had 1 foot in day and 1 foot in night Orbital sunset," said Garan via Twitter of this picture. Credit: NASA
A view of the Cupola on the ISS, and if you look closely, you can see faces of several of the Atlantis STS-135 and Expediton 28 crewmembers looking out the windows. Credit: NASA
Another view of Mike Fossum during the spacewalk. Credit: NASA
A close-up view of Mike Fossum during the final EVA of the shuttle era. Credit: NASA
With his feet secured on a restraint on Canadarm2, Mike Fossum holds the Robotics Refueling Mission payload. The failed pump module is with DEXTRE in the upper left corner of the photo. The blue color on the space station module is a reflection from the blue of planet Earth. Credit: NASA
"Knocking on the door to come back in from space after yesterday's spacewalk," said Ron Garan via Twitter. Credit: NASA
Following the six-hour, 31-minute EVA, spacewalkers Ron Garan (top left) and Mike Fossum (top right), pose in the ISS’s Quest airlock with Chris Ferguson, STS-135 commander, Doug Hurley, pilot, and Rex Walheim, mission specialist. Credit: NASA
Here’s how astronauts train for their EVAs, in the Neutral Buoyancy Laboratory (NBL) near NASA's Johnson Space Center. Here astronauts Rex Walheim and Sandy Magnus (mostly obscured), are raised from the waters of the N as a spacewalk training session comes to a close. Divers were in the water to assist Magnus and Walheim in their rehearsal. Credit: NASA

For larger versions of any of these images, and to see more images from the STS-135 mission, see NASA’s Human Spaceflight website’s mission gallery.

Posted on by Tammy Plotner

MAXI Peers Into Black Hole Binaries

X-ray all-sky image obtained by MAXI's first 10-month observation Bright X-ray sources (mainly binaries comprising neutron stars and black holes) exist in large numbers around the Galactic Center (in the direction of Sagittarius) and along the Galactic Plane (Milky Way) and change from day to day. Colors indicate the "hardness" of X-ray spectrum. More than 200 X-ray sources including weak ones have been identified. Credit: JAXA

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The Monitor of All-sky X-ray Image, or MAXI for short, spends its time aboard the ISS conducting a full sky survey every 92 minutes. Its sole purpose is to monitor X-ray source activity and report. Unlike stars seen in visible light, X-ray sources aren’t evenly distributed and can exhibit some highly unusual behavior. What causes these erratic moments? Read on…

“Most visible stars shine with energies generated by nuclear fusion in their cores. In these stars, if the energy generated in their core increases more than usual, the whole object expands and eventually lowers the core temperature. In this way, negative feedback is activated to stabilize the nuclear reaction. For this reason, these stars shine very stably for most of their lifetime.” says Nobuyuki Kawai of the Tokoyo Institute of Technology. “On the other hand, the energy source of most intense X-ray sources is gravitational energy released when the gas surrounding extremely compact bodies like black holes and neutron stars is accreted onto them. The normal stars’ stabilizing mechanism does not work in this process, and accordingly, X-ray intensity fluctuates in response to changes in the supply of gas from the surrounding area.”

This means MAXI needs to keep a close watch on both known and unknown X-ray sources for activity. Catching it as it happens allows an alert to be posted to other observatories for monitoring and study. Right now the focus has been on MAXI’s 18 month study of black hole binaries – the most famous of which is Cygnus X-1. It is well-known this famous source shines brilliantly in the X-ray spectrum, but it switches between a “hard” and “soft” state. These periods of high and low energy may be directly related to the density of gas which surrounds it.

“We can get a clue to estimate the mass of a black hole by examining the X-ray intensity and radiation spectrum in the soft state. As a result of analysis of the motion of the companion star rotating the center of gravity of the binary system, we found that Cygnus X-1 is a remarkably smaller object than normal stars, with an X-ray source mass about 10 times the solar mass but which emits hardly any visible light.” says Professor Kawai. “If applying star theory, such an object must be a black hole.”

Right now astronomers are studying gas properties and estimate there are about 20 binary X-ray sources other than Cygnus X-1. Most of these black hole binaries are considered to be “X-ray nova” – showing activity anywhere from every few years to only once in the four decades we’ve been studying them in this light. With the help of MAXI’s sensitive all-sky monitoring, researchers now stand a chance of being able to monitor activity from beginning to end. Has it been successful? You bet. When black hole binary, XTE J1752-223, was discovered by the routine patrol of RXTE, MAXI also detected the emergence of this new X-ray nova and was able to observe all the activities until it disappeared in April 2010. On September 25, 2010 MAXI and the Swift satellite discovered black hole binary MAXI J1659-152 almost simultaneously allowing it to be observed by researchers and amateur astronomers around the world.

“In addition to these black hole binaries, MAXI has achieved many interesting observations including: detection of the largest flare from active galactic nuclei in X-ray observation history; discovery of a new binary X-ray pulsar, MAXI J1409-619; and detection of a number of intense star flares.” says Kawai. “As long as the ISS is operating, we will use MAXI to monitor the X-ray sky, which changes restlessly and violently.”

Original Story Source: Japan Aerospace Exploration Agency.

Posted on by Jon Voisey

New Planet Discovered In Trinary Star System

A planet 6 times the mass of Earth orbits around the star Gliese 667 C, which belongs to a triple system. Credit: ESO

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Until recently, astronomers were highly skeptical of whether or not planets should be possible in multiple star systems. It was expected that the constantly varying gravitational force would eventually tug the planet out of orbit. But despite doubts, astronomers have found several planets in just such star systems. Recently, astronomers announced another, this time in the trinary star HD 132563.

The detection of the new planet came as part of a larger study on the trinary star system spanning 10 years. The two main stars that comprise the system are both similar to the Sun in mass, although somewhat less prevalent in metals, and orbit each other at a distance of around 400 AU. The main star, HD 132563A is also itself, a binary. This fact was not previously recognized and also reported by the team, led by Silvano Desidera from the Astronomical Observatory in Padova, Italy.

The newly discovered planet orbits the secondary star in the system, HD 132563B. As with the binary component of the main star, the new planet was discovered spectroscopically. The planet is at least 1.3 times the mass of Jupiter, with an average distance from its parent star of 2.6 AU, and an moderately high eccentricity of 0.22.

The team also attempted to image the planet directly using adaptive optics from the Italian Telescopio Nazionale Galileo. While there was a hint in the glare of the star that may have been the planet in question, the team could not rule out that the detection was not an instrumental effect.

With the discovery of this new planet, the total number of discovered planets in multiple star systems lies at eight. while this is rather small numbers from which to draw firm conclusions, it appears that planets can be commonly found orbiting the more remote members of trinary star systems for good periods of time. On the shorter end, the stellar system is anticipated to be 1-3 billion years in aged, based on the amount of stellar activity and amount of lithium present in the star’s atmosphere (which decreases with time). However, fitting of the mass and luminosity onto isochrones suggest the stars may be as much as 5 billion years in age. In either situation, the planetary system is dynamically stable.

Also based on these eight systems, the team also suggests that planets existing around such far removed members of a multiple star system may be as common as planets around wide binaries, or even single stars.

Posted on by Nancy Atkinson

How Does the Aurora Borealis Form?

Seeing the Northern or Southern Lights is an awe-inspiring experience, but do you know the science behind their beauty? This video from Per Byhring and the physics department at the University of Oslo explains how particles originating from deep inside the core of the Sun creates aurorae in the atmosphere of Earth.

The video takes a look at how cloud of electrically charged particles emanate from the Sun, and what happens when this plasma reaches the Earth and interacts with the planet’s magnetic field, which creates fantastic light shows in the extreme northern and southern latitudes.

Via Scientific American

Posted on by Nancy Atkinson

XCOR Lynx Slated to Fly New Suborbital Telescope

Artist rendering of the XCOR Lynx outfitted with the Atsa Suborbital Observatory. Credit: XCOR

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Commercial space company XCOR Aerospace has signed a “Memorandum of Understanding” with the Planetary Science Institute, laying the groundwork for flying a human-operated telescope on board XCOR’s Lynx spacecraft. The Atsa Suborbital Observatory is a specially designed telescope for use in suborbital space vehicles, and when used with commercial suborbital vehicles, PSI says it will provide low-cost space-based observations above the contaminating atmosphere of Earth, while avoiding some operational constraints of satellite telescope systems.

“The XCOR vehicle design and capabilities work well for hosting the kind of observing facility we are developing,” said PSI Senior Scientist Faith Vilas, the Atsa Project Scientist.

“NASA has been flying suborbital observatories for decades, on unmanned, disposable rockets. The new manned, reusable commercial platforms will allow us to make repeated observations with a single instrument, but without the need to refurbish it between flights,” said Luke Sollitt, and affiliate scientist with PSI and a co-inventor with Vilas of the Atsa Observatory. “In addition, the short turn-around means we can do many observations or targets.”

Atsa means “eagle” in the Navajo language. The facility is optimized for observing solar system objects near the sun that are difficult to study from orbital observatories such as Hubble and ground-based telescopes.

The Lynx flight profile. Credit: XCOR

The Lynx is a two-seat, piloted space transport vehicle, capable of taking humans and payloads on a half-hour suborbital flight to 100 km (330,000 feet) and then return safely to a landing at the takeoff runway, providing 4-6 minutes of weightless flight.

Like an aircraft, Lynx is a horizontal takeoff and horizontal landing vehicle, but instead of a jet or piston engine, Lynx uses its own fully reusable rocket propulsion system to depart a runway and return safely.

The Atsa Observatory will be mounted on the top of the Lynx in an experiment pod. XCOR or PSI did not release the cost per flight, but XCOR’s price for one passenger is $95,000 USD. In contrast, the price for using sounding rockets vary, depending on how high the rocket goes, but some cost as little as $10,000 USD.

“These are natural targets for instruments on suborbital rockets to observe, but a human-tended facility using the kind of reusable launch vehicle offered by XCOR offers significant cost savings,” said Mark Sykes, CEO and Director of PSI, who is also a long-time planetary astronomer and is training to be an Atsa operator.

The Lynx spacecraft will fly to space on a customized flight trajectory and will be capable of precision pointing, allowing the Atsa system with its operator to acquire the desired target and make the planned observations. “We are being approached by many potential customers who are interested in supporting observations of the inner solar system,” Vilas said. “We will also be able to support target of opportunity observations for newly discovered objects and other phenomena.”

“We’re looking forward to flying PSI’s Atsa system on Lynx, it will be a groundbreaking experience. The rapid and flexible operations of the Lynx will enable scientists to pick specific targets of interest and the same day fly multiple tailor made observation missions quickly and inexpensively when they want them to be flown,” said Khaki Rodway McKee, XCOR’s Program Manager.

“We are entering into a new era in the human exploration of space, where private companies like XCOR and PSI will begin to play leading roles in certain areas, beginning with suborbital flight – harkening back to the days of NASA’s Mercury program,” Sykes said.

Andrew Nelson, XCOR’s Chief Operating Officer, said, “Much like the early days of the Internet, mobile communications and social networking revolutions saw new and innovative applications drive commercial multi-billion dollar marketplaces, so we are seeing privately funded efforts like PSI’s Atsa as a key early adopter signaling a robust future for suborbital reusable launch vehicles.”

Source: PSI

Posted on by Nancy Atkinson

Zubrin Claims VASIMR is a Hoax

Artist rendering of the VASIMR powered spacecraft heading to Mars. Credit: Ad Astra

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A next-generation plasma rocket being developed by former NASA astronaut Franklin Chang Diaz called the Variable Specific Impulse Magnetoplasma Rocket (VASIMR) has been touted as a way to get astronauts to Mars in weeks rather than months, as well as an innovative, cheap way to re-boost the International Space Station. But in a biting commentary posted on Space News and the Mars Society website, “Mars Direct” advocate Robert Zubrin calls VASIMR a “hoax” saying the engine “is neither revolutionary nor particularly promising. Rather, it is just another addition to the family of electric thrusters, which convert electric power to jet thrust, but are markedly inferior to the ones we already have,” adding, “There is thus no basis whatsoever for believing in the feasibility of Chang Diaz’s fantasy power system.”

The VASIMR uses plasma as a propellant. A gas is ionized using radio waves entering into a plasma state. As ions the plasma can be directed and accelerated by a magnetic field to create specific thrust. The purported advantage of the VASIMR lies in its ability to change from high impulse to low impulse thrust as needed, making it an ideal candidate for a mission beyond low Earth orbit.

Chang Diaz’ company, the Ad Astra Rocket Company successfully tested the VASIMR VX-200 plasma engine in 2009. It ran at 201 kilowatts in a vacuum chamber, passing the 200-kilowatt mark for the first time. “It’s the most powerful plasma rocket in the world right now,” said Chang-Diaz at the time. Ad Astra has signed a Space Act agreement with NASA to test a 200-kilowatt VASIMR engine on the International Space Station, reportedly in 2013.

The tests would provide periodic boosts to the space station, which gradually drops in altitude due to atmospheric drag. ISS boosts are currently provided by spacecraft with conventional thrusters, which consume about 7.5 tons of propellant per year. By cutting this amount down to 0.3 tons, Chang-Diaz estimates that VASIMR could save NASA millions of dollars per year.

For the engine to enable trips to Mars in a reported 39 days, a 10- to 20-megawatt VASIMR engine ion engine would need to be coupled with nuclear power to dramatically shorten human transit times between planets.

Robert Zubrin. Credit: The Mars Society

Zubrin is the president of the Mars Society and author of the book “The Case for Mars: The Plan to Settle the Red Planet and Why We Must.” He has long touted the “Mars Direct” approach of getting humans to Mars to create a sustainable human settlement. The plan includes a series of unmanned and human flights to Mars using existing technology, as well as “living off the land” on Mars by creating rocket fuel to return to Earth, and using underground reservoirs of water on Mars.

In his commentary on VASIMR, Zubrin says, “existing ion thrusters routinely achieve 70 percent efficiency and have operated successfully both on the test stand and in space for thousands of hours. In contrast, after 30 years of research, the VASIMR has only obtained about 50 percent efficiency in test stand burns of a few seconds’ duration.”

On the ‘39 days to Mars’ claim, Zubrin says VASIMR would need to couple with a nuclear reactor system with a power of 200,000 kilowatts and a power-to-mass ratio of 1,000 watts per kilogram, while the largest space nuclear reactor ever built, the Soviet Topaz, had a power of 10 kilowatts and a power-to-mass ratio of 10 watts per kilogram.

Zubrin has invited Chang Diaz to a formal public debate the VASIMR at a Mars Society convention in Dallas next month.

Read Zubrin’s commentary on Space News or the Mars Society website.

More info: Ad Astra Rocket Company

Posted on by Nancy Atkinson

3-D Atlantis in Flight

A 3-D view of Atlantis during the RBAR pitch maneuver while approaching the space station. Credit: NASA, 3-D by Nathanial Burton-Bradford. Click for larger view on Flickr.

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Time to grab your 3-D glasses (the red/cyan kind, please) and see a couple of 3-D views of Atlantis during her final flight. Above, she’s doing the belly flip, the RBAR pitch maneuver while approaching the station, and 3-D wizard Nathanial Burton-Bradford has 3-D-ified the view. Below is a 3-D look at Atlantis’ launch. Thanks to Nathanial for sharing his images with Universe Today. See his Flickr page for more!

Atlantis' final launch on July 8, 2011. Credit: NASA, 3-D by Nathanial Burton-Bradford. Click for larger view on Flickr.