Archive for June 6, 2013

NASA’s Spitzer Sees Milky Way’s Blooming Countryside

June 6, 2013 1 comment

Image credit: NASA/JPL-Caltech/University of Wisconsin

Image credit: NASA/JPL-Caltech/University of Wisconsin

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.”

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Young Star Suggests Our Sun Was A Feisty Toddler

Artist's conception. Credit: David A. Aguilar (CfA)

Artist’s conception. Credit: David A. Aguilar (CfA)

If you had a time machine that could take you anywhere in the past, what time would you choose? Most people would probably pick the era of the dinosaurs in hopes of spotting a T. rex. But many astronomers would choose the period, four and a half billion years ago, that our solar system formed.

In lieu of a working time machine, we learn about the birth of our Sun and its planets by studying young stars in our galaxy. New work suggests that our Sun was both active and “feisty” in its infancy, growing in fits and starts while burping out bursts of X-rays.

“By studying TW Hydrae, we can watch what happened to our Sun when it was a toddler,” said Nancy Brickhouse of the Harvard-Smithsonian Center for Astrophysics (CfA). She presented the findings today in a press conference at a meeting of the American Astronomical Society.

Brickhouse and her colleagues reached this conclusion by studying the young star TW Hydrae, located about 190 light-years from Earth in the southern constellation Hydra the Water Snake. TW Hydrae is an orange, type K star weighing about 80 percent as much as our Sun. It is about 10 million years old, and is still accreting gas from a surrounding disk of material. That same disk might contain newborn planets.

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Cat’s Paw Nebula “Littered” With Baby Stars

Credit: S. Willis (CfA); NASA/JPL-Caltech/SSC

Credit: S. Willis (CfA); NASA/JPL-Caltech/SSC

Most skygazers recognize the Orion Nebula, one of the closest stellar nurseries to Earth. Although it makes for great views in backyard telescopes, the Orion Nebula is far from the most prolific star-forming region in our galaxy. That distinction may go to one of the more dramatic stellar nurseries like the Cat’s Paw Nebula, otherwise known as NGC 6334, which is experiencing a “baby boom.”

“NGC 6334 is forming stars at a more rapid pace than Orion – so rapidly that it appears to be undergoing what might be called a burst of star formation,” said lead author Sarah Willis of the Harvard-Smithsonian Center for Astrophysics (CfA) and Iowa State University. “It might resemble a ‘mini-starburst,’ similar to a scaled-down version of the spectacular bursts sometimes seen in other galaxies.”

NGC 6334 is a realm of extremes. The nebula contains about 200,000 suns’ worth of material that is coalescing to form new stars, some with up to 30 to 40 times as much mass as our Sun. It houses tens of thousands of recently formed stars, more than 2,000 of which are extremely young and still trapped inside their dusty cocoons. Most of these stars are forming in clusters where the stars are spaced up to a thousand times closer than the stars in the Sun’s neighborhood.

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NASA’s GRAIL Mission Solves Mystery Of Moon’s Surface Gravity

NASA’s Gravity Recovery and Interior Laboratory (GRAIL) mission has uncovered the origin of massive invisible regions that make the moon’s gravity uneven, a phenomenon that affects the operations of lunar-orbiting spacecraft.

Because of GRAIL’s findings, spacecraft on missions to other celestial bodies can navigate with greater precision in the future.

GRAIL’s twin spacecraft studied the internal structure and composition of the moon in unprecedented detail for nine months. They pinpointed the locations of large, dense regions called mass concentrations, or mascons, which are characterized by strong gravitational pull. Mascons lurk beneath the lunar surface and cannot be seen by normal optical cameras.

“GRAIL data confirm that lunar mascons were generated when large asteroids or comets impacted the ancient moon, when its interior was much hotter than it is now,” said Jay Melosh, a GRAIL co-investigator at Purdue University in West Lafayette, Ind.

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“Population Census” Of Galaxies Buried In Dust

A research team led by Bunyo Hatsukade, a postdoc researcher, and Kouji Ohta, a professor, both from the Graduate School of Science, Kyoto University, revealed that approximately 80% of the unidentifiable millimeter wave signals from the universe is actually emitted from galaxies, based on the observations with ALMA (Atacama Large Millimeter/submillimeter Array). ALMA’s high resolving power and sensitivity enables us to pinpoint the locations of those galaxies rich in fine solid particles (dust).

With the ALMA telescope, the research team observed the “Subaru/XMM-Newton Deep Survey Field” in the direction of the constellation Cetus, and succeeded in identifying 15 extremely dark galaxies which had been previously unknown. In addition, they also successfully measured the number density of galaxies with 10 times less luminosity than ones previously observed with the conventional millimeter instruments. Their densities well match the prediction by theories of galaxy formation. Therefore, the researchers consider that they managed to capture more like “normal” galaxies, which had been impossible to detect up to now, than extremely bright “submillimeter-luminous galaxies”. Using ALMA and the Subaru Telescope, the research team is now seeking to uncover the overall picture of galaxy formation and evolution while conducting observations of much darker galaxies.

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Music Of The Spheres: Star Songs

Plato, the Greek philosopher and mathematician, described music and astronomy as “sister sciences” that both encompass harmonious motions, whether of instrument strings or celestial objects. This philosophy of a “Music of the Spheres” was symbolic. However, modern technology is creating a true music of the spheres by transforming astronomical data into unique musical compositions.

Gerhard Sonnert, a research associate at the Harvard-Smithsonian Center for Astrophysics, has published a new website that allows listeners to literally hear the music of the stars. He worked with Wanda Diaz-Merced, a postdoctoral student at the University of Glasgow whose blindness led her into the field of sonification (turning astrophysical data into sound); and with composer Volkmar Studtrucker, who turned the sound into music.

“I saw the musical notes on Wanda’s desk and I got inspired,” Sonnert says.

Diaz-Merced lost her sight in her early 20s while studying physics. When she visited an astronomy lab and heard the hiss of a signal from a radio telescope, she realized that she might be able to continue doing the science she loved. She now works with a program called xSonify, which allows users to present numerical data as sound and use pitch, volume, or rhythm to distinguish between different data values.

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