Spitzer Finds New Stars At Edge Of Milky Way
June 6, 2013

Spitzer Telescope Discovers Blooming Stars On Milky Way’s Fringe

April Flowers for redOrbit.com - Your Universe Online

New images from NASA´s Spitzer Space Telescope reveal blooming stars at the fringe of the Milky Way galaxy, far from its crowded core.

The images were collected as part of the Galactic Legacy Infrared Mid-Plane Survey Extraordinaire (Glimpse 360) project. Glimpse 360 is mapping the celestial topography of our galaxy and will make the map and a full 360-degree view of the Milky Way plane that will be available later this year. The Glimpse 360 images will be open to the public, who are invited to help catalog features.

The Milky Way is a spiral galaxy that is mostly flat like a vinyl record. Unlike that record, the Milky Way is slightly warped. Our Solar System is in the Orion Spur, an offshoot of the Perseus spiral arm, about two-thirds of the way from the center of the galaxy. The infrared observations from Spitzer are allowing scientists to map the shape of the galaxy and its warp with more precision than ever before.

In the past, Spitzer and other telescopes have been used to create mosaics of the galaxy´s plane looking towards its center. The area behind us, which has sparse stars and dark skies, is less charted, however. "We sometimes call this flyover country," said Barbara Whitney, a University of Wisconsin at Madison astronomer 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."

The team of researchers is using the Spitzer data to find new sites of youthful stars. They spotted an area near Canis Major, for example, with 30 or more stars spouting jets of material. These jets, which represent an early phase of life for the stars, have been found in 163 regions using the Glimpse 360 data. Some of the young stars are highly clustered in packs while others stand alone.

Robert Benjamin, assistant professor of physics at the University of Wisconsin, led the Spitzer research team to more carefully pinpoint the distances to stars in the galaxy´s hinterlands. A distinct and rapid drop-off of red giants, a type of older star, has been observed at the edge of the galaxy. The team is 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 Benjamin, 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."

Improved images of those remote stellar lands are being captured thanks to Spitzer´s infrared instruments, while NASA´s Wide-field Infrared Survey Explorer (WISE) helps to fill in the gaps in areas Spitzer did not cover. The WISE mission, completed in early 2011, was to survey the entire sky twice in infrared light. Spitzer is still active, probing the infrared sky in greater detail. The combined results are helping scientists to canvas our sky, filling in blanks in the outer expanses.

The Glimpse 360 project has already mapped 130 degrees of the sky around the center of the galaxy. Four new views from the area looking away from the galactic center are already available online.

Earlier Glimpse data is being scoured by members of the public in search of cosmic bubbles that indicate hot, massive stars. This citizen scientist activity, called the Milky Way Project, has added to astronomers´ knowledge of how massive stars influence the formation of other stars. Volunteers have identified a striking multiple bubble structure in a star-forming region called W39. Researchers followed up on this identification, showing the smaller bubbles were spawned by a larger bubble 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."