http://www.eurekalert.org/pub_releases/2003-01/dlnl-apt010703.php
Public release date: 7-Jan-2003
Contact: Anne Stark
[EMAIL PROTECTED]
925-422-9799
DOE/Lawrence Livermore National Laboratory
Astronomers poised to apply novel way to look for comets beyond Neptune
SEATTLE, Washington- Lawrence Livermore National Laboratory astronomers are
major partners in a scientific collaboration that will conduct an extremely
novel search for small, comet-like bodies in the outer solar system using
four half-meter telescopes. The work was described today at the winter
meeting of the American Astronomical Society.
Rather than look for the light reflected directly by these objects (as is
customary astronomy practice), this project will search for those very rare
moments when one of these objects passes between the telescopes and a nearby
background star. This brief "eclipse" lasts less than a second, but will
allow the scientists to study objects that are much too faint to be seen in
reflected sunlight, even with the largest telescopes.
This work was presented today by Sun-Kung King, on behalf of the TAOS
Project (TAOS: Taiwanese-American Occultation Survey) and by Matthew Lehner
of the University of Pennsylvania. King is an astronomer from the Institute
of Astronomy and Astrophysics of the Academia Sinica in Taiwan. Lawrence
Livermore National Laboratory scientists have played a key role in the
design and building of the telescopes and are members of TAOS.
The region probed by TAOS is known as the Kuiper Belt, and sometimes as the
Edgeworth-Kuiper Belt, after the two scientists who independently proposed
its existence more than 50 years ago. There were only two objects (Pluto and
its moon Charon) known in this region until the 1990s, when a flood of
exciting discoveries of new bodies was started by David Jewitt (at the
University of Hawaii) and Jane Luu (then at UC Berkeley). Despite hundreds
of discoveries later, much more remains unknown.
All theories of this region predict that there are many more small objects
than large objects. Conventional telescope searches principally find objects
that are larger in diameter than about 100 kilometers. An ambitious program
with the Hubble Space Telescope may find objects as small as 10 kilometers
in size. The scientists in TAOS believe they will be able to extend this
lower limit to about 3 kilometers. It is believed there are billions of
objects this small in the outer solar system.
"The TAOS survey will provide data on remnants of our early solar system and
early planet formation," said Kem Cook, a TAOS astronomer who works at
Livermore's Institute for Geophysics and Planetary Physics. "It will provide
us insight into how the solar system evolved. We'll be looking at the
smallest objects than anyone else has seen."
Current observations and theories can say very little about regions many
times farther from the sun than Neptune. TAOS is unique among astronomical
surveys in its ability to probe these great distances. TAOS is able to do
this because it does not rely on reflected sunlight. These small objects are
thought to be directly related to the new comets that wander into the
planetary system. Composed of dust and ice, they begin to evaporate when
they come closer to the sun, producing the spectacular and beautiful tails
that astronomers believe are the oldest objects in the solar system, which
makes them especially interesting.
"The small objects we will detect are much too faint to be seen directly,
even by the largest telescopes in the world," King said. "We will find them
silhouetted against the background stars, which will make it possible for us
to detect them."
TAOS will consist of four telescopes (only half a meter in diameter), which
will be used to monitor up to 2,000 stars. The telescopes will operate in
the central highlands of Taiwan.
The optical performance of the TAOS telescopes proved difficult to achieve
in a compact design.
"We depended on LLNL precision engineering, optical design and fabrication
capabilities to build these telescopes," Cook said. "Without that expertise
we would not have been able to build the TAOS telescopes."
The TAOS collaboration is made up of: King, A. Wang, C.Y. Wen, S.Y. Wang,
and T. Lee from the Academia Sinica's Institute of Astronomy and
Astrophysics in Taiwan; C. Alcock, R. Dave, J. Giammarco and Lehner from the
University of Pennsylvania; Cook, S. Marshall and R. Porrata from the
Lawrence Livermore National Laboratory; W.P. Chen and Z.W. Zhang from the
National Central University in Taiwan; Y.I. Byun from Yonsei University in
South Korea; J. Lissauer from NASA's Ames Research Center; and I. De Pater,
C. Liang and J. Rice from UC Berkeley.
TAOS is funded by the Academia Sinica and the National Central University,
which receive support from the Ministry of Education and the National
Science Council in Taiwan; by the Korean Research Foundation in South Korea;
and by NASA at the University of Pennsylvania and the Lawrence Livermore
National Laboratory.
###
Founded in 1952, Lawrence Livermore National Laboratory is a national
security laboratory, with a mission to ensure national security and apply
science and technology to the important issues of our time. Lawrence
Livermore National Laboratory is managed by the University of California for
the U.S. Department of Energy's National Nuclear Security Administration.
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