[meteorite-list] Partial Ingredients for DNA and Protein Found Around Star

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Tue Dec 20 18:43:03 2005
Message-ID: <200512202341.jBKNfSe27787_at_zagami.jpl.nasa.gov>

MEDIA RELATIONS OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109 TELEPHONE (818) 354-5011
http://www.jpl.nasa.gov

Whitney Clavin (818) 354-4673
Jet Propulsion Laboratory, Pasadena, Calif.

News Release: 2005-175 Dec. 20, 2005

Partial Ingredients for DNA and Protein Found Around Star

NASA's Spitzer Space Telescope has discovered some of life's
most basic ingredients in the dust swirling around a young
star. The ingredients - gaseous precursors to DNA and protein -
were detected in the star's terrestrial planet zone, a region
where rocky planets such as Earth are thought to be born.

The findings represent the first time that these gases, called
acetylene and hydrogen cyanide, have been found in a terrestrial
planet zone outside of our own.

"This infant system might look a lot like ours did billions of
years ago, before life arose on Earth," said Fred Lahuis of
Leiden Observatory in the Netherlands and the Dutch space
research institute called SRON. Lahuis is lead author of a
paper to be published in the Jan. 10 issue of the Astrophysical
Journal Letters.

Lahuis and his colleagues spotted the organic, or
carbon-containing, gases around a star called IRS 46. The star
is in the Ophiuchus (pronounced OFF-ee-YOO-kuss), or "snake
carrier," constellation about 375 light-years from Earth. This
constellation harbors a huge cloud of gas and dust in the
process of a major stellar baby boom. Like most of the young
stars here and elsewhere, IRS 46 is circled by a flat disk of
spinning gas and dust that might ultimately clump together to
form planets.

When the astronomers probed this star's disk with Spitzer's
powerful infrared spectrometer instrument, they were surprised
to find the molecular "barcodes" of large amounts of acetylene
and hydrogen cyanide gases, as well as carbon dioxide gas. The
team observed 100 similar young stars, but only one, IRS 46,
showed unambiguous signs of the organic mix.

"The star's disk was oriented in just the right way to allow us
to peer into it," said Lahuis.

The Spitzer data also revealed that the organic gases are hot.
So hot, in fact, that they are most likely located near the star,
about the same distance away as Earth is from our sun.

"The gases are very warm, close to or somewhat above the boiling
point of water on Earth," said Dr. Adwin Boogert of the California
Institute of Technology, Pasadena. "These high temperatures helped
to pinpoint the location of the gases in the disk."

Organic gases such as those found around IRS 46 are found in our
own solar system, in the atmospheres of the giant planets and
Saturn's moon Titan, and on the icy surfaces of comets. They have
also been seen around massive stars by the European Space Agency's
Infrared Space Observatory, though these stars are thought to be
less likely than sun-like stars to form life-bearing planets.

Here on Earth, the molecules are believed to have arrived billions
of years ago, possibly via comets or comet dust that rained down
from the sky. Acetylene and hydrogen cyanide link up together in
the presence of water to form some of the chemical units of life's
most essential compounds, DNA and protein. These chemical units are
several of the 20 amino acids that make up protein and one of the
four chemical bases that make up DNA.

"If you add hydrogen cyanide, acetylene and water together in a
test tube and give them an appropriate surface on which to be
concentrated and react, you'll get a slew of organic
compounds including amino acids and a DNA purine base called
adenine," said Dr. Geoffrey Blake of Caltech, a co-author of the
paper. "And now, we can detect these same molecules in the planet
zone of a star hundreds of light-years away."

Follow-up observations with the W.M. Keck Telescope atop Mauna Kea
in Hawaii confirmed the Spitzer findings and suggested the presence
of a wind emerging from the inner region of IRS 46's disk. This
wind will blow away debris in the disk, clearing the way for the
possible formation of Earth-like planets.

The Jet Propulsion Laboratory manages the Spitzer Space Telescope
mission for NASA's Science Mission Directorate, Washington. Science
operations are conducted at the Spitzer Science Center at Caltech.
JPL is a division of Caltech. Spitzer's infrared spectrograph was
built by Cornell University, Ithaca, N.Y. Its development was led
by Dr. Jim Houck of Cornell.

For graphics and more information about Spitzer, visit

http://www.spitzer.caltech.edu/spitzer .

For more information about NASA and agency programs on the Web,
visit

http://www.nasa.gov/home/ .

-end-
Received on Tue 20 Dec 2005 06:41:27 PM PST