NASA's WISE Catches Aging Star Erupting With Dust

April 26, 2012

J.D. Harrington
Headquarters, Washington
202-358-5241
j.d.harrington@nasa.gov

Whitney Clavin
Jet Propulsion Laboratory, Pasadena, Calif.
818-354-4673
whitney.clavin@jpl.nasa.gov

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.

For more information about WISE, visit:

http://www.nasa.gov/wise


-end-



To subscribe to the list, send a message to:
hqnews-subscribe@mediaservices.nasa.gov
To remove your address from the list, send a message to:
hqnews-unsubscribe@mediaservices.nasa.gov