NASA's Spitzer Sees Milky Way's Blooming Countryside

RELEASE : 13-168 NASA's Spitzer Sees Milky Way's Blooming Countryside WASHINGTON -- New views from NASA's Spitzer Space Telescope show blooming stars in our Milky Way galaxy's more barren territories, far from its crowded core.

The images are part of the Galactic Legacy Infrared Mid-Plane Survey Extraordinaire (Glimpse 360) project, which is mapping the celestial topography of our galaxy. The map and a full, 360-degree view of the Milky Way plane will be available later this year. Anyone with a computer may view the Glimpse images and help catalog features.

We live in a spiral collection of stars that is mostly flat, like a vinyl record, but it has a slight warp. Our solar system is located about two-thirds of the way out from the Milky Way's center, in the Orion Spur, an offshoot of the Perseus spiral arm. Spitzer's infrared observations are allowing researchers to map the shape of the galaxy and its warp with the most precision yet.

While Spitzer and other telescopes have created mosaics of the galaxy's plane looking in the direction of its center before, the region behind us, with its sparse stars and dark skies, is less charted.

"We sometimes call this flyover country," said Barbara Whitney, an astronomer from the University of Wisconsin at Madison, who uses Spitzer to study young stars. "We are finding all sorts of new star formation in the lesser-known areas at the outer edges of the galaxy."

Whitney and colleagues are using the data to find new sites of youthful stars. For example, they spotted an area near Canis Major with 30 or more young stars sprouting jets of material, an early phase in their lives. So far, the researchers have identified 163 regions containing these jets in the Glimpse 360 data, with some of the young stars highly clustered in packs and others standing alone.

Robert Benjamin is leading a University of Wisconsin team that uses Spitzer to more carefully pinpoint the distances to stars in the galaxy's hinterlands. The astronomers have noticed a distinct and rapid drop-off of red giants, a type of older star, at the edge of the galaxy. They are using this information to map the structure of the warp in the galaxy's disk.

"With Spitzer, we can see out to the edge of the galaxy better than before," said Robert Benjamin of the University of Wisconsin, who presented the results Wednesday at the 222nd meeting of the American Astronomical Society in Indianapolis. "We are hoping this will yield some new surprises."

Thanks to Spitzer's infrared instruments, astronomers are capturing improved images of those remote stellar lands. Data from NASA's Wide-field Infrared Survey Explorer (WISE) are helping fill in gaps in the areas Spitzer did not cover. WISE was designed to survey the entire sky twice in infrared light, completing the job in early 2011, while Spitzer continues to probe the infrared sky in more detail. The results are helping to canvas our galaxy, filling in blanks in the outer expanses where not much is known.

Glimpse 360 already has mapped 130 degrees of the sky around the galactic center. Four new views from the area looking away from the galactic center are online at:

http://go.nasa.gov/ZtA1Sn 

Members of the public continue scouring images from earlier Glimpse data releases in search of cosmic bubbles indicative of hot, massive stars. Astronomers' knowledge of how massive stars influence the formation of other stars is benefitting from this citizen science activity, called The Milky Way Project. For instance, volunteers identified a striking multiple bubble structure in a star-forming region called W39. Follow up work by the researchers showed the smaller bubbles were spawned by a larger bubble that had been carved out by massive stars.

"This crowdsourcing approach really works," said Charles Kerton of Iowa State University at Ames, who also presented results. "We are examining more of the hierarchical bubbles identified by the volunteers to understand the prevalence of triggered star formation in our galaxy."

For more information about the Milky Way project and to learn how to participate, visit:

http://www.milkywayproject.org

More information about Spitzer is at: http://www.nasa.gov/spitzer

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NASA's Orion Spacecraft Proves Sound Under Pressure

RELEASE : 13-174 NASA's Orion Spacecraft Proves Sound Under Pressure WASHINGTON -- After a month of being poked, prodded and pressurized in ways that mimicked the stresses of spaceflight, NASA's Orion crew module successfully passed its static loads tests on Wednesday.

When Orion launches on Exploration Flight Test-1 (EFT-1), which is targeted for September 2014, it will travel farther from Earth than any spacecraft built for humans in more than 40 years. The spacecraft will fly about 3,600 miles above Earth's surface and return at speeds of approximately 25,000 mph. During the test, Orion will experience an array of stresses, or loads, including launch and reentry, the vacuum of space, and several dynamic events that will jettison hardware away from the spacecraft and deploy parachutes.

To ensure Orion will be ready for its flight test next year, engineers at NASA's Kennedy Space Center in Florida built a 20-foot-tall static loads test fixture for the crew module with hydraulic cylinders that slowly push or pull on the vehicle, depending on the type of load being simulated. The fixture produced 110 percent of the load caused by eight different types of stress Orion will experience during EFT-1. More than 1,600 strain gauges recorded how the vehicle responded. The loads ranged from as little as 14,000 pounds to as much as 240,000 pounds.

"The static loads campaign is our best method of testing to verify what works on paper will work in space," said Charlie Lundquist, NASA's Orion crew and service module manager at the agency's Johnson Space Center in Houston. "This is how we validate our design."

In addition to the various loads it sustained, the Orion crew module also was pressurized to simulate the effect of the vacuum in space. This simulation allowed engineers to confirm it would hold its pressurization in a vacuum and verify repairs made to superficial cracks in the vehicle's rear bulkhead caused by previous pressure testing in November.

The November test revealed insufficient margin in an area of the bulkhead that was unable to withstand the stress of pressurization. Armed with data from that test, engineers were able to reinforce the design to ensure structural integrity and validate the fix during this week's test.

To repair the cracks, engineers designed brackets that spread the stress of being pressurized to other areas of the module that are structurally stronger. During these tests Orion was successfully pressurized to 110 percent of what it would experience in space, demonstrating it is capable of performing as necessary during EFT-1.

For information about Orion, visit:

http://www.nasa.gov/orion

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NASA's Hubble Maps 3-D Structure of Ejected Material Around Erupting Star

J.D. Harrington
Headquarters, Washington                                  
202-358-5241
j.d.harrington@nasa.gov
Ray Villard
Space Telescope Science Institute, Baltimore
410-338-4514
villard@stsci.edu
RELEASE : 13-172 NASA's Hubble Maps 3-D Structure of Ejected Material Around Erupting Star WASHINGTON -- A flash of light from a stellar outburst has provided a rare look at the 3-D structure of material ejected by an erupting nova.

Astronomers used NASA's Hubble Space Telescope to observe the light emitted by the close double-star system T Pyxidis, or T Pyx, a recurring nova, during its latest outburst in April 2011.

A nova erupts when a white dwarf, the burned-out core of a sun-like star, has siphoned off enough hydrogen from a companion star to trigger a thermonuclear runaway. As hydrogen builds up on the surface of the white dwarf, it becomes hotter and denser until it detonates like a colossal hydrogen bomb, leading to a 10,000-fold increase in brightness in a little more than one day. Nova explosions are extremely powerful, equal to a blast of one million billion tons of dynamite. T Pyx erupts every 12 to 50 years.

Contrary to some predictions, the astronomers were surprised to find the ejecta from earlier outbursts stayed in the vicinity of the star and formed a disk of debris around the nova. The discovery suggests material continues expanding outward along the system's orbital plane, but it does not escape the system.

"We fully expected this to be a spherical shell," says Arlin Crotts of Columbia University, a member of the research team. "This observation shows it is a disk, and it is populated with fast-moving ejecta from previous outbursts."

Team member Stephen Lawrence of Hofstra University in Hempstead, N.Y., will present the results Tuesday at the American Astronomical Society meeting in Indianapolis.

Team member Jennifer Sokoloski, also of Columbia University and co-investigator on the project, suggests these data indicate the companion star plays an important role in shaping how material is ejected, presumably along the system's orbital plane, creating the pancake-shaped disk. The disk is tilted about 30 degrees from face-on toward Earth.

Using Hubble's Wide Field Camera 3, the team took advantage of the blast of light emitted by the erupting nova to trace the light's path as it lit up the disk and material from previous ejecta. The disk is so vast, about a light-year across, that the nova's light cannot illuminate all of the material at once. Instead, the light sweeps across the material, sequentially illuminating parts of the disk, a phenomenon called a light echo. The light reveals which parts of the disk are nearer to Earth and which sections are farther away. By tracing the light, the team assembled a 3-D map of the structure around the nova.

"We've all seen how light from fireworks shells during the grand finale will light up the smoke and soot from shells earlier in the show," Lawrence said. "In an analogous way, we're using light from T Pyx's latest outburst and its propagation at the speed of light to dissect its fireworks displays from decades past."

Although astronomers have witnessed light propagating through material surrounding other novae, this is the first time the immediate environment around an erupting star has been studied in three dimensions.

Astronomers have studied light echoes from other novae, but those phenomena illuminated interstellar material around the stars instead of material ejected from them.

The team also used the light echo to refine estimates of the nova's distance from Earth. The new distance is 15,600 light-years from Earth. Previous estimates were between 6,500 and 16,000 light-years. T Pyx is located in the southern constellation Pyxis, or the Mariner's Compass.

The team is continuing to analyze the Hubble data to develop an outflow model. T Pyx has a history of outbursts. Besides the 2011 event, other previous known eruptions were seen in 1890, 1902, 1920, 1944, and 1966.

Astronomers call erupting stars novae, Latin for "new," because they abruptly appear in the sky. A nova quickly begins to fade in several days or weeks as the hydrogen is exhausted and blown into space.

The team also includes Helena Uthas of Columbia University. The team's results will appear online Wednesday, June 5 and will be published in the June 20 issue of the Astrophysical Journal Letters. Sokoloski is the paper's lead author.

For images, and more information about T Pyxidis, visit:

http://hubblesite.org/news/2013/21

For more information about NASA's Hubble Space Telescope, visit: http://www.nasa.gov/hubble

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