|
|
|
|
|
Planets prefer safe neighborhoods, Spitzer finds UNIVERSITY OF ARIZONA NEWS RELEASE Posted: October 3, 2006 A star must live in a relatively tranquil cosmic neighborhood to foster planet formation, say astronomers using NASA's Spitzer Space Telescope.
According to Zoltan Balog, lead author of the team's paper, the super-sensitive infrared eyes of Spitzer are ideal for capturing the "photoevaporation" of these planet-forming disks. In this process, immense output from the O star heats the disks that are surrounding nearby sun-like stars so much that gas and dust boil off (much like the evaporation of boiling water), and the disk can no longer hold together. Photon (or light) blasts from the O star then blow away the evaporated material, potentially stripping the sun-like stars of their ability to form planets. "We can see that these systems take on a cometary structure as they are being blown away and destroyed," Balog said. "No other telescope has ever captured the photoevaporation of a protoplanetary disk in this much detail," added Kate Su, who is a co-author on Balog's paper. The photoevaporation process is very similar to the one that forms the tail of a comet as it swings by the inner solar system, only a lot more violent and on a far larger scale, Su said. "Every time a particle of light from the O star hits a dust grain in the nearby protoplanetary disk, the light particle pushes the dust grain away from its host star," Su said. "This is very similar to how comet tails form." "Unfortunately these sun-like stars just got a little too close to the fire," UA Regents Professor George Rieke said. Rieke is also a co-author on the paper and the principal investigator for Spitzer's Multiband Imaging Photometer (MIPS) instrument, which made the new observations. Ultimately, the astronomers hope to determine whether all stars have planets, and if not, how a star loses the ability to form them. The Spitzer findings will help astronomers understand what regulates the process of planet formation. Team members say that originally they were looking for "diskless stars" in their survey, stars that had ventured too close to an O star and no longer had any disk left. With so many O stars in the region, they didn't expect that a protoplanetary disk would survive for very long. However, they found something different - stars that had recently blundered into the hostile neighborhood of an O star and were still in the process of losing their disks. "To see protoplanetary disks in an area where no one expected to see one is very exciting," Balog said. "But to see a disk in the process of evaporating is even more thrilling." Balog's paper was recently accepted for publication in Astrophysical Journal. He is currently is at the University of Arizona on leave from the Department of Optics and Quantum Electronics, University of Szeged, Hungary. UA astronomers James Muzerolle and Erick T. Young collaborated with Balog, Rieke and Su in the observations. |
|
|
|
 |
|||||||||||||||||||||
After its safe landing to end mission STS-115, space shuttle Atlantis is towed from the Kennedy Space Center runway to hangar 1 of the Orbiter Processing Facility for post-flight deservicing and the start of preparations leading to its next mission, STS-117.
Space shuttle Atlantis glides to a smooth touchdown on Kennedy Space Center's Runway 33 at 6:21 a.m. to conclude the successful STS-115 mission that restarted construction of the space station.
The Russian Soyuz TMA-9 space capsule carrying the Expedition 14 resident crew and space tourist Anousheh Ansari safely docks to the International Space Station's Zvezda service module.
This extended duration movie follows the Soyuz rocket from the final countdown through arrival in orbit with the Expedition 14 crew. The video shows the three-stage rocket's ascent from Baikonur Cosmodrome and includes views of Mike Lopez-Alegria, Mikhail Tyurin and Anousheh Ansari from cameras inside the capsule.
The voyage of Expedition 14 aboard the International Space Station is expected to see major construction activities for the outpost. Learn more about the mission in this narrated mission preview movie.
The Hubble Space Telescope has become astronomy's crown jewel for knowledge and discovery. The great observatory was placed high above Earth following its launch aboard space shuttle Discovery on April 24, 1990. The astronauts of STS-31 recount their mission in this post-flight film presentation.
The long voyage of exploration to Jupiter and its many moons by the Galileo spacecraft began on October 18, 1989 with launch from Kennedy Space Center aboard the space shuttle Atlantis. The crew of mission STS-34 tell the story of their flight to dispatch the probe -- fitted with an Inertial Upper Stage rocket motor -- during this post-flight presentation film.