Apr 26 2012

From The Space Library

RELEASE: 12-131 NASA'S WISE CATCHES AGING STAR ERUPTING WITH DUST

WASHINGTON -- Images from NASA's Wide-field Infrared Survey Explorer (WISE) reveal an old star in the throes of a fiery outburst and spraying the cosmos with dust. The findings offer a rare, real-time look at the process by which stars like our sun seed the universe with building blocks for other stars, planets and even life. The star, catalogued as WISE J180956.27--330500.2, was discovered in images taken during the WISE survey in 2010, the most detailed infrared survey to date of the entire celestial sky. It stood out from other objects because it glowed brightly with infrared light. When compared to images taken more than 20 years ago, astronomers found the star was 100 times brighter. "We were not searching specifically for this phenomenon, but because WISE scanned the whole sky, we can find such unique objects," said Poshak Gandhi of the Japan Aerospace Exploration Agency (JAXA), lead author of a new paper to be published in the Astrophysical Journal Letters. Results indicate the star recently exploded with copious amounts of fresh dust, equivalent in mass to our planet Earth. The star is heating the dust and causing it to glow with infrared light. "Observing this period of explosive change while it is actually ongoing is very rare," said co-author Issei Yamamura of JAXA. "These dust eruptions probably occur only once every 10,000 years in the lives of old stars, and they are thought to last less than a few hundred years each time. It's the blink of an eye in cosmological terms." The aging star is in the "red giant" phase of its life. Our own sun will expand into a red giant in about 5 billion years. When a star begins to run out of fuel, it cools and expands. As the star puffs up, it sheds layers of gas that cool and congeal into tiny dust particles. This is one of the main ways dust is recycled in our universe, making its way from older stars to newborn solar systems. The other way, in which the heaviest of elements are made, is through the deathly explosions, or supernovae, of the most massive stars. "It's an intriguing glimpse into the cosmic recycling program," said Bill Danchi, WISE program scientist at NASA Headquarters in Washington. "Evolved stars, which this one appears to be, contribute about 50 percent of the particles that make up humans." Astronomers know of one other star currently pumping out massive amounts of dust. Called Sakurai's Object, this star is farther along in the aging process than the one discovered recently by WISE. After Poshak and his team discovered the unusual, dusty star with WISE, they went back to look for it in previous infrared all-sky surveys. The object was not seen at all by the Infrared Astronomical Satellite (IRAS), which flew in 1983, but shows up brightly in images taken as part of the Two Micron All-Sky Survey (2MASS) in 1998. Poshak and his colleagues calculated the star appears to have brightened dramatically since 1983. The WISE data show the dust has continued to evolve over time, with the star now hidden behind a very thick veil. The team plans to follow up with space and ground-based telescopes to confirm its nature and to better understand how older stars recycle dust back into the cosmos. NASA's Jet Propulsion Laboratory (JPL), Pasadena, Calif., manages and operates WISE for NASA's Science Mission Directorate in Washington. The spacecraft was put into hibernation mode after it scanned the entire sky twice, completing its main objectives. The principal investigator for WISE, Edward Wright, is at the University of California, Los Angeles. The mission was selected competitively under NASA's Explorers Program managed by the agency's Goddard Space Flight Center in Greenbelt, Md. The science instrument was built by the Space Dynamics Laboratory in Logan, Utah. The spacecraft was built by Ball Aerospace & Technologies Corp. in Boulder, Colo. Science operations and data processing take place at the Infrared Processing and Analysis Center at the California Institute of Technology (Caltech) in Pasadena. Caltech manages JPL for NASA. The IRAS mission was a collaborative effort between NASA (JPL), the Netherlands and the United Kingdom. The 2MASS mission was a joint effort between Caltech, the University of Massachusetts and NASA (JPL). Data are archived at the Infrared Processing and Analysis Center at Caltech.

RELEASE: 12-132 NASA SEEKS GAME CHANGING SOLAR ARRAY SYSTEMS PROPOSALS

WASHINGTON -- NASA's Space Technology Program is seeking proposals to develop solar array systems to enable space electric propulsion systems of the future. "NASA's Game Changing Development Program focuses on maturing advanced space technologies that may lead to entirely new approaches for the agency's future space missions," said Michael Gazarik, director of NASA's Space Technology Program at the agency's Headquarters in Washington. "This call for proposals will result in the development of revolutionary space solar array systems that can be scaled for future human exploration missions to destinations well beyond low Earth orbit." NASA's Space Technology program is seeking proposals for solar array system structures from all potential U.S. organizations, including NASA centers and other government agencies, federally funded research and development centers, educational institutions, industry and nonprofit organizations. "This call for proposals is a great opportunity to mature advanced and innovative solar array systems in preparation for a space demonstration and eventual use on all future space spacecraft requiring high power," said Stephen Gaddis, Game Changing Development program manager at NASA's Langley Research Center in Hampton, Va. The NASA solicitation will cover two acquisition phases and involve a competitive selection process. During Phase I, proposers will design, analyze and test a scalable solar array system capable of generating more than 30kW of power. The Phase I teams also will identify the most critical technological risks of extending their concept to 250 kW or greater power levels. The intent of Phase II is to prove flight readiness through an in-space demonstration of an advanced, modular and extendable solar array system. After Phase II, follow-on applications will range from high power communications satellites to solar electric propulsion systems. NASA expects to make up to three awards for Phase I proposals, with total combined costs of approximately $15 to $20 million, based on availability of funds. This solicitation is an appendix to NASA's Game Changing Opportunities in Technology Development research announcement and can be found through the NASA Solicitation and Proposal Integrated Review and Evaluation System. NASA's Langley Research Center in Hampton, Va., manages the Game Changing Development Program and will oversee the technical aspects of this technology development effort under Phase I. NASA's Glenn Research Center in Cleveland will manage the awarded contracts for the agency's Space Technology Program under both phases.

RELEASE: 12-136 NASA'S CASSINI FINDS SATURN'S MOON PHOEBE HAS PLANET-LIKE QUALITIES

WASHINGTON -- Data from NASA's Cassini mission reveal Saturn's moon Phoebe has more planet-like qualities than previously thought. Scientists had their first close-up look at Phoebe when Cassini began exploring the Saturn system in 2004. Using data from multiple spacecraft instruments and a computer model of the moon's chemistry, geophysics and geology, scientists found Phoebe was a so-called planetesimal, or remnant planetary building block. The findings appear in the April issue of the Journal Icarus. "Unlike primitive bodies such as comets, Phoebe appears to have actively evolved for a time before it stalled out," said Julie Castillo-Rogez, a planetary scientist at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif. "Objects like Phoebe are thought to have condensed very quickly. Hence, they represent building blocks of planets. They give scientists clues about what conditions were like around the time of the birth of giant planets and their moons" Cassini images suggest Phoebe originated in the far-off Kuiper Belt, the region of ancient, icy, rocky bodies beyond Neptune's orbit. Data show Phoebe was spherical and hot early in its history, and has denser rock-rich material concentrated near its center. Its average density is about the same as Pluto, another object in the Kuiper Belt. Phoebe likely was captured by Saturn's gravity when it somehow got close to the giant planet. Saturn is surrounded by a cloud of irregular moons that circle the planet in orbits tilted from Saturn's orbit around the sun, the so-called equatorial plane. Phoebe is the largest of these irregular moons and also has the distinction of orbiting backward in relation to the other moons. By comparison, Saturn's large moons appear to have formed from gas and dust around the planet's equatorial plane and orbit in that same plane. "By combining Cassini data with modeling techniques previously applied to other solar system bodies, we've been able to go back in time and clarify why Phoebe is so different from the rest of the Saturn system," said Jonathan Lunine, a co-author on the study and a Cassini team member at Cornell University. Analyses suggest that Phoebe was born within the first 3 million years of the birth of the solar system, which occurred 4.5 billion years ago. The moon originally may have been porous but appears to have collapsed in on itself as it warmed up. Phoebe developed a density 40 percent higher than the average inner Saturnian moon. Objects of Phoebe's size have long been thought to form as potato-shaped bodies and remain that way over their lifetimes. If such an object formed early enough in the solar system's history, it could have harbored the kinds of radioactive material that would produce substantial heat over a short timescale. This would warm the interior and reshape the moon. "From Cassini images and models, we were able to see that Phoebe started with a nearly spherical shape, rather than an irregular shape later smoothed into a sphere by impacts," said co-author Peter Thomas, a Cassini team member at Cornell. Phoebe likely stayed warm for tens of millions of years before freezing up. The study suggests the heat also would have enabled the moon to host liquid water at one time. This could explain the signature of water-rich material on Phoebe's surface previously detected by Cassini. The new study also is consistent with the idea that several hundred million years after Phoebe cooled, the moon drifted toward the inner solar system in a solar-system-wide rearrangement. Phoebe was large enough to survive this turbulence. More than 60 moons are known to orbit Saturn, varying drastically in shape, size, surface age and origin. Scientists using both ground-based observatories and Cassini's cameras continue to search for others. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL manages the mission for the agency's Science Mission Directorate in Washington.

MEDIA ADVISORY: M12-077 SHUTTLE ENTERPRISE TO FLY OVER NEW YORK CITY METRO AREA FRIDAY

WASHINGTON -- NASA managers, in consultation with Intrepid Sea, Air and Space Museum officials, have selected Friday, April 27, to ferry space shuttle Enterprise from Washington Dulles International Airport to John F. Kennedy (JFK) International Airport in New York. NASA's 747 Shuttle Carrier Aircraft (SCA) with Enterprise mounted atop will fly at a relatively low altitude over various parts of the New York City metropolitan area on Friday. The aircraft is expected to fly near a variety of landmarks, including the Statue of Liberty and Intrepid. After the flyover is complete, the SCA will land at JFK. The Federal Aviation Administration is coordinating the flight, which is scheduled to occur between 9:30 and 11:30 a.m. EDT. The timing and exact route depend on weather and operational constraints. If the flight is postponed for any reason, a notice will be issued. Media will have access to the public areas at Dulles to view the departure of Enterprise. Media sending crews to Dulles should contact the Metropolitan Washington Airports Authority Office of Public Affairs at 703-417-8370. During the weeks following the arrival, Enterprise will be demated from the 747 and placed on a barge that will be moved by tugboat up the Hudson River to Intrepid in June. The shuttle will be lifted by crane and placed on the flight deck of the Intrepid where it will be on exhibit to the public starting this summer in a temporary climate-controlled pavilion. The Intrepid continues to work on a permanent exhibit facility to showcase Enterprise that will enhance the museum's space-related exhibits and education curriculum.